MK3.5

<p><strong>MK4 to MK4S upgrade <br /></strong></p>
<p>The current lead time is <strong>1-2 weeks </strong>for both xLCD versions. <br /><em>Due to high demand, we cannot guarantee delivery of this product before Christmas.</em></p>
<h3><span style="font-size: 20px;">Current lead time estimates for new orders</span></h3>
<p><span style="color: #e67e23;"><strong>Updated: December 17th, 2024 </strong></span></p>
<p><em>The dates are only an estimation at the date of update, specified above, and rely on the actual</em> production. <em>We're doing our best but please be aware that it can shift for the lead time products. We will update here and on the product pages accordingly.</em></p>
<p>The lead time estimate applies to standalone products, other products in the order may increase the lead time.</p>
<p>If you've ordered a product in a bundle, the lead time of the order is set based on the product in the bundle with the longest lead time.</p>
<p><strong>Due to high demand, we cannot guarantee delivery of the following products before Christmas.</strong></p>
<p></p>
<table class="table" style="border-collapse: collapse; height: 930.875px; border-style: ridge; width: 100%;" border="1">
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<h4>Product</h4>
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<td style="height: 60.875px; width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center;">
<h4>Lead time</h4>
</td>
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<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>MK4 to MK4S upgrade</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>1-2 weeks</strong></p>
</td>
</tr>
<tr style="height: 51px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>MK3.9 to MK3.9S upgrade</strong></p>
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<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>1-2 weeks</strong></p>
</td>
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<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>MK3S/+ to MK4S upgrade</strong></p>
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<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>4-5</strong><strong> weeks</strong></p>
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</tr>
<tr style="height: 51px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>MK3S/+ to MK3.9S upgrade</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>1-2 weeks</strong></p>
</td>
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<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>MK3S/S+ to MK3.5S</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>1-2 weeks</strong></p>
</td>
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<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>Original Prusa MK4S</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>1-2 weeks</strong></p>
</td>
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<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>Original Prusa MK4S kit</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>4-5 weeks</strong></p>
</td>
</tr>
<tr style="height: 51px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>Original Prusa XL</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>1-2 weeks</strong></p>
</td>
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<tr style="height: 72px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>Original Prusa MMU3 upgrade kit <br />(all printer models)</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>1-2 weeks</strong></p>
</td>
</tr>
<tr style="height: 72px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>Original Prusa MMU2S to MMU3 upgrade<br />(MK3.9/S &amp; MK4/S)</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>4-5 weeks</strong></p>
</td>
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<tr style="height: 72px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>Original Prusa MMU3 assembled unit<br />(MK3.9/S &amp; MK4/S)</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>4-5 weeks</strong></p>
</td>
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<tr style="height: 72px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>Original Prusa MMU3 assembled unit<br />(MK3S+ &amp; MK3.5/S)</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>1-2 weeks</strong></p>
</td>
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<tr style="height: 51px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>Original Prusa XL Enclosure</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>1-2 weeks</strong></p>
</td>
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<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>Original Prusa MINI Enclosure</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>1-2 weeks</strong></p>
</td>
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<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>Original Prusa MK Enclosure </strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>4-5 weeks</strong></p>
</td>
</tr>
</tbody>
</table>
<p>You can find your order shipping date in the order detail section in our shop.</p>
<div class="note-callout">All products purchased in our <a href="https://shop.prusa3d.com/">online store</a> are currently being shipped from the<strong> Czech Republic, </strong>a member state of the <strong>European Union, customs charges may apply for shipments to countries outside of the EU!</strong> Please see our advisory article <a href="http://help.prusa3d.com/article/vat-value-added-tax-customs-fees_1505#orders-outside-eu">here</a>.</div>

Shipping information

Infill patterns

<p>The First Layer Calibration is used to calibrate the distance between the tip of the nozzle and the print surface. The aim is to adjust the nozzle height until the extruded plastic sticks nicely to the bed and you can see that it is being slightly squished.</p>
<p>The printers assembled in the Prusa factory are already fine-tuned and this calibration is needed only in case you build the kit version at home or change the nozzle. The First Layer Calibration is part of the Wizard (last step of the XYZ-Calibration). You can also recalibrate the first layer later on from the <em>LCD-menu - Calibration - First Layer Calibration</em>. During this process, rotate the knob to manually adjust the distance between the nozzle and the bed, while the printer is printing a zig-zag pattern.</p>
<div class="warning-callout">As <strong>each type of sheet (smooth, satin, and textured) has a different thickness</strong> you must use a different First layer calibration for each of them. For this, we have a convenient feature called <a href="http://help.prusa3d.com/article/steel-sheet-profiles_1955">Steel sheet profiles</a>.</div>
<p>With a newly assembled printer, you will start at zero and move into a negative (-) value, reducing the distance between nozzle and heat bed. The initial zero-value is set by the P.I.N.D.A./SuperPINDA. position. <strong>Turn the knob counter-clockwise to bring the nozzle closer to the bed and moving the value away from zero. </strong>The value is unique to each printer and it may also slightly change with time and use. You must, therefore, <strong>check visually when adjusting the height, not by a set value. </strong></p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/first_layer-768x433-1.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/first_layer-768x433-1-600x338.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/first_layer-768x433-1-300x169.jpg 300w" alt="" width="600" height="338" loading="lazy" /></p>
<p>The first layer calibration being set incorrectly can lead to various issues. With the nozzle too far from the print surface, you risk your print not sticking properly, which can result in a <a href="http://help.prusa3d.com/article/extruder-blob_2005">blob</a>. On the other side, if set too close, you can experience extrusion problems and <a href="http://help.prusa3d.com/article/clogged-nozzle-hotend-mk3-5-s-mk3s-mk2-5s_2008">clogging</a> and poor print quality, <strong>or even damage to the hardware, like the <a href="http://help.prusa3d.com/article/flexible-steel-sheets-guidepost_2195">Flexible steel sheet</a> due to the print sticking too much.</strong> It is therefore <strong>important to get this right.</strong></p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-01.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-01-300x62.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-01-600x125.jpg 600w" width="600" height="125" loading="lazy" data-hd-align="center" /></p>
<p>Before you proceed, make sure that the print surface (satin, smooth, or textured steel-sheet) is clean. You can find information on how to clean it in <a href="http://help.prusa3d.com/article/first-layer-issues_1804">PEI print surface preparation</a>. There are some small differences between how it should look on the textured and smooth steel sheet. We will, therefore, present pictures and guidelines for both, starting with the smooth sheet.</p>
<div>
<div class="note-callout" style="text-align: center;"><strong>Turn the knob counter-clockwise to bring the nozzle closer to the bed.</strong></div>
</div>
<h3>Smooth sheet</h3>
<h4>Too high</h4>
<p><strong>You want the line flattened, but not squished.</strong> On the square at the end of the test line, you do not want any <strong>gaps between the lines (<span style="color: #e03e2d;">left picture</span>), which means it is too high. </strong>In that case, the value will be too close to zero</p>
<h4>Too low</h4>
<p>If the nozzle is set too low (<span style="color: #e03e2d;">right picture</span>) you will see the line squished completely flat and the end square will have <strong>ridges between the lines, which is a clear sign it is set too low</strong> and the value will be too far away from zero. When it is too low, the edges of the square can also start curling upwards. In the extreme, the filament will be spread so thin you will be able to see through the printed filament, leading to clogging of your hotend.</p>
<div class="warning-callout">Having the nozzle too low can cause the nozzle to damage your steel sheet. This is not covered by <a href="http://help.prusa3d.com/article/warranty_2288">Warranty</a>.</div>
<h4>Just right</h4>
<p>A correct adjustment will show you an even surface (<span style="color: #2dc26b;">center picture</span>), with no gaps between lines, nor ridges. As stated, the numeric value depends on the exact position of the P.I.N.D.A./SuperPINDA sensor, which will be unique to each machine and means nothing without a visual reference. <strong>However, a common range is from -0.400 to -1.500.</strong></p>
<p><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-02.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-02-300x119.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-02-600x238.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-02-768x305.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-02-800x318.jpg 800w" /></p>
<div class="note-callout">Adjusting it closer can in some cases improve adhesion. However, if you are having problems with adhesion, but your first layer calibration looks like the 'good' picture (<span style="color: #2dc26b;">center picture</span>), your problem lies somewhere else, like a dirty/greasy sheet, print-settings, bed leveling/XYZ calibration, or under-extrusion.</div>
<p><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-03fix-2.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-03fix-2-600x214.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-03fix-2-800x286.jpg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-03fix-2-300x107.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-03fix-2-768x274.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-03fix-2-1536x548.jpg 1536w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-03fix-2-2048x731.jpg 2048w" alt="" width="1121" height="400" loading="lazy" /></p>
<div class="warning-callout"><strong>You can not use the same first layer calibration if you swap between the Smooth and the textured sheet! </strong>For more information, please see <a href="http://help.prusa3d.com/article/steel-sheet-profiles_1955">Steel sheet profiles</a>.</div>
<h3>Textured sheet</h3>
<p>The textured sheets are thinner than the sheets with smooth PEI, therefore you need to move the nozzle bit closer, but you are seeking the same results as with the smooth sheet. Again, if <strong>it is set too low (<span style="color: #e03e2d;">right picture</span>) the filament can start curling up</strong> around the edges like it is not adhering. The numeric value will be too far from zero and must be adjusted back.</p>
<p>If set too high, you will see the line being round, and have gaps between the lines of the end-square. In this case, the value is too close to zero.</p>
<p><img decoding="async" title="https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-04-300x119.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-04-600x238.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-04-768x305.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-04-800x318.jpg 800w" src="https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-04.jpg" /></p>
<h3>Have a look at the nozzle</h3>
<p>A single layer is about 0.2 mm / 0.00787402 inch. Having a look at the nozzle and its distance to the sheet can also be helpful. However, measuring the printed layer with calipers is not a recommended method to calibrate the first layer.</p>
<p><img decoding="async" title="https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-05-300x119.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-05-600x238.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-05-768x305.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-05-800x318.jpg 800w" src="https://cdn.help.prusa3d.com/wp-content/uploads/First-Layer-Calibration-05.jpg" /></p>
<h3>When to run the First layer calibration</h3>
<p>Generally, the <strong>first layer calibration</strong> should be performed every time there is a <strong>major change in the assembly.</strong> This includes changing the nozzle, extruder upgrades, or other updates to any axis. You should also run all calibrations if you move the printer to a different location.</p>
<div class="tip-callout">For First Layer Calibrations with other nozzle diameters than 0.4 mm, please see <a href="http://help.prusa3d.com/article/different-nozzle-types_2193#first-layer-calibration-of-other-nozzles">this article</a></div>
<h3>Other issues</h3>
<ul>
<li>If the width of the line varies across its length, you may have to do some <a href="http://help.prusa3d.com/article/bed-level-correction_2267">Bed Level Correction</a>.</li>
<li>If the nozzle comes in contact with the bed, the SuperPINDA/P.I.N.D.A. leveling sensor is not being triggered by the flexible steel sheet and must be physically moved lower in its holder. This will bring it closer to the level of the nozzle tip. You should make sure it is adjusted as instructed in the <a href="http://help.prusa3d.com/guide/9-preflight-check_76792">Preflight check</a> in the Assembly manual. <strong>If you move the leveling sensor you must redo the First layer calibration.</strong></li>
</ul>

First Layer Calibration (i3)

<div class="warning-callout">This is an&nbsp;<strong>advanced calibration</strong>, recommended only to&nbsp;<strong>experienced users</strong>.</div>
<p>The Extrusion Multiplier allows the fine-tuning of the extrusion flow rate - simply described as&nbsp;<strong>how much filament comes out of the nozzle</strong>. In other words, the&nbsp;<strong>Extrusion Multiplier</strong>&nbsp;setting in PrusaSlicer and the&nbsp;<strong>Flow rate</strong>&nbsp;setting in printer firmware are two ways to adjust the same thing, however, adjusting one of those two settings will not influence the value of the other.</p>
<p><strong>This procedure is not necessary with a new printer coming from the factory</strong>, but rather applies for specific applications and filaments. The ideal value is different for every type of material and every color. It can even differ from spool to spool. Bear this in mind if you change type and brand of filament often or use cheap no-name brands.</p>
<div class="note-callout">Total flow rate = <strong>Flow multiplier</strong> in firmware (M221) x <strong>Extrusion multiplier</strong> in PrusaSlicer. For those interested in diving deeper, PrusaSlicer uses the same <a href="https://manual.slic3r.org/advanced/flow-math">Flow math as Slic3r</a>.</div>
<h3><strong>How to spot an issue</strong></h3>
<p>This calibration is used to fix two common problems:</p>
<ul>
<li><strong>Overextrusion</strong> - Too much material is extruded (flow is too high). It causes scarring of bottom layers and unnecessary material buildup on top layers.</li>
<li><strong>Minor under extrusion</strong>&nbsp;- Not enough material is extruded (flow is too low). It causes small gaps that appear between layer lines or perimeters.</li>
</ul>
<p><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over-600x282.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over-800x376.jpg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over-300x141.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over-768x361.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over-1536x721.jpg 1536w" alt="" width="852" height="400"></p>
<p><strong>Overextrusion</strong> is a common problem with many filament brands. It's especially problematic when you're trying to glue two parts of the model. <strong>If the top layer is over extruded, you'll end up with an uneven surface that will prevent a seamless connection between the two pieces.</strong></p>
<h3><strong>How to do the calibration</strong></h3>
<p>In PrusaSlicer, navigate to <span class="key">Filament Settings</span> and look for Extrusion Multiplier. The default setting (for PLA) is 1, this value represents a percentage, 1 = 100%, 0.95 = 95% etc. Usually, the adjusted values can be between 0.9 and 1.1. To adjust it, simply rewrite the value.</p>
<p><img decoding="async" style="max-height: 200px; display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusuki/prusuki-images/image-2019-1-15-12-55-6.png" data-hd-height="200px"></p>
<p>In the printer menu, during a print, go to the Tune menu and then choose Flow. Again, the usual values can range between 90 and 110, although that does not mean you can't go above or below that.</p>
<h4>Which method should I use?</h4>
<p>There are two methods you can use to calibrate the Extrusion Multiplier, and we'll cover both of them in this article:</p>
<ul>
<li><strong>Precise Method</strong>&nbsp; -&nbsp; using precision tools such as calipers or micrometers.</li>
<li><strong>Visual Method&nbsp;</strong>&nbsp;- an easy method based on observing the visual properties of your models.</li>
</ul>
<p>The choice of the method depends entirely on your preferences; in the end, both yield similar results. Even the visual method will enable you to have perfectly fitting parts with smooth &amp; flat top layers.</p>
<h4>Precise Method</h4>
<div class="note-callout">Please note that the following guide is based on <strong>default</strong> PrusaSlicer 0.4 nozzle profiles, with a layer height of 0.1mm - 0.2mm. This means that:<br />
- Nozzle size = 0.4<br />
- Extrusion width =&nbsp;0.45<br />
- Basic materials (PLA, ABS, PETG) Extrusion Multiplier = 1<br />
<strong>If you wish to calibrate the printer with a bigger/smaller nozzle or layer heights above 0.2, then you will need to adjust these values as well.</strong></div>
<ol>
<li>Download the <a href="https://cdn.help.prusa3d.com/wp-content/uploads/2021/04/cube-40-40-40.zip">Precision Method Cube STL</a>.</li>
<li>Slice it using the Vase Mode and your most-often used layer height and print it. You can find Vase mode (Print Settings →&nbsp; Layers and perimeters →&nbsp; Spiral vase).</li>
<li>Make three or more measurements in the middle of each wall and calculate the overall average thickness.</li>
<li>Calculate the extrusion multiplier using the following formula: <strong>Extrusion multiplier = (Extrusion width (0.45) / Average measured wall thickness)</strong>.</li>
<li>Adjust the Extrusion Multiplier in Filament Settings → Filament</li>
<li>Re-print the cube with new settings and go back to step 3 if necessary.</li>
</ol>
<p><img decoding="async" style="max-height: 220px; display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusuki/prusuki-images/micrometer-small-jpg.JPG" height="400" data-hd-height="220px"></p>
<div class="warning-callout">Please note that cheap digital calipers may not be accurate enough to make reliable measurements of a single perimeter wall.</div>
<h4>Visual Method</h4>
<p>This method does not require any tools, only your sight. The point is to make sure your top layers are <strong>smooth</strong>, <strong>shiny,</strong> and without <strong>scarring or filament buildup</strong> near the perimeters.</p>
<p><img decoding="async" loading="lazy" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/destiky6.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/destiky6-600x374.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/destiky6-800x499.jpg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/destiky6-300x187.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/destiky6-768x479.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/destiky6-1536x958.jpg 1536w" alt="" width="641" height="400"></p>
<ol>
<li>Download the <a href="https://cdn.help.prusa3d.com/wp-content/uploads/2021/04/visual-method-cube.zip">Visual Method Cube.stl</a></li>
<li>Slice it using the default Prusa PLA presets at 0.20mm layer height and print it.</li>
<li>Inspect the top layer of your cube visually and with the tip of the finger.</li>
<li>If the top is under extruded or not smooth, then re-adjust the Extrusion Multiplier accordingly by 1-2%.</li>
<li>Repeat the steps above as long as needed.</li>
</ol>
<p>If there is&nbsp;<strong>too much material</strong>&nbsp;near the perimeters,&nbsp;<strong>decrease</strong>&nbsp;the Extrusion Multiplier value.</p>
<p><img decoding="async" style="max-height: 390px; margin-left: auto; margin-right: auto; display: block;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusuki/prusuki-images/buildu.jpg" data-hd-height="390px" data-hd-align="left"></p>
<p>If there are&nbsp;<strong>visible gaps</strong>&nbsp;between layer lines,&nbsp;<strong>increase</strong> the Extrusion Multiplier value. (Microscopic gaps near the perimeters are OK.)</p>
<p><img decoding="async" style="max-height: 430px; margin-left: auto; margin-right: auto; display: block;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusuki/prusuki-images/gaps.jpg" data-hd-height="430px" data-hd-align="left"></p>


Extrusion multiplier calibration

<div><strong><img decoding="async" loading="lazy" style="float: right;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-768x768.jpg 768w" alt="" width="225" height="225"></strong></div>
<h3>Basic info</h3>
<div><strong>PETG</strong> is one of the most easily printable materials, it is <strong>inexpensive and suitable for beginners</strong>. Relatively high tenacity and temperature resistance make it <strong>suitable for printing technical parts</strong> (for example parts of our printers).</div>
<div>&nbsp;</div>
<div><strong>Recommended nozzle temperature:</strong> 230 °C for the first layer, 240 °C for the other layers</div>
<div>&nbsp;</div>
<div><strong>Recommended bed temperature:</strong> 85 °C for the first layer, 90 °C for the other layers</div>
<div>&nbsp;</div>
<div><strong>Heatbed:</strong> Using powder-coated TXT or satin sheet is highly recommended. Printing on smooth PEI surface might damage the sheet.</div>
<h3>Description</h3>
<div>
<p><a href="https://www.prusa3d.com/category/prusament-petg/"><strong data-stringify-type="bold">PETG</strong></a> (Polyethylene Terephthalate modified with Glycol) is a commonly used technical material, popular among 3D printer users for its <strong>low price and good printability</strong>. It’s tenacious, with good temperature resistance; PETG is most commonly used for printing various mechanical parts, holders, clamps, and waterproof parts (thanks to great layer adhesion).</p>
<p>PETG has a glossy surface, adheres greatly to a print sheet, and <strong>does not shrink or warp</strong> (it has very little thermal expansion), therefore it’s suitable for printing large models. Plus, its high tenacity and flexibility often <strong>prevent it from breaking.</strong> Due to good temperature resistance, PETG parts are suitable both for interior and most exterior use (with temperatures below 80 °C). <strong>Parts of our printers are made of PETG!</strong></p>
<p>The letter G in PETG means that it’s modified with glycol during the manufacturing process. Glycol makes PET less brittle, easier to print, and more transparent for translucent prints. Of course, you can print also with PET filaments without glycol. However, printing with only PET is challenging and does not offer any advantage whatsoever.</p>
<div class="warning-callout">Even though PETG in itself may be considered <a href="http://help.prusa3d.com/article/food-safe-fdm-printing_112313">food-safe</a>, it consists of layers, as every 3D print, in which bacteria can grow over time. You can prevent this by applying a <strong>food-safe(epoxy) coating.</strong> Also, a stainless-steel nozzle should be used for if food is the intended application.</div>
<p>Although <strong>PETG</strong> is frequently used in <strong>food industry</strong> and is considered <strong>food-safe</strong>, we do not recommend it (or any other filament) for printing dishes or other stuff that comes into direct contact with food. The main reason is tiny print layer surface grooves that can support numerous bacterial colonies. But if you still want 3D printed dishes, we suggest <strong>applying a special layer</strong> that seals the surface (food-safe coating) and printing with a clean steel nozzle.</p>
<p>Some of the manufacturers <strong>enrich PETG with various additives</strong> and sell these materials under different names. For example, Spoolworks EDGE by E3D is modified PET/Copolyester Blend with additives. The goal is to acquire better visual qualities, surface and layer adhesion, etc.</p>
<p>To compare supported material properties, see our <a href="https://help.prusa3d.com/en/materials">material table.</a></p>
</div>
<table class="striped">
<tbody>
<tr>
<th>
<p>Pros</p>
</th>
<th>
<p>Cons</p>
</th>
</tr>
<tr>
<td>
<p>✔ Easy to print</p>
</td>
<td>
<p>✖ Possibility of stringing</p>
</td>
</tr>
<tr>
<td>
<p>✔ Good layer adhesion</p>
</td>
<td>
<p>✖ Poor bridging and overhangs</p>
</td>
</tr>
<tr>
<td>
<p>✔ Tough and durable</p>
</td>
<td>
<p>✖ Not great for printing detailed parts</p>
</td>
</tr>
<tr>
<td>
<p>✔ Low warping</p>
</td>
<td>
<p>✖ Bonds strongly to the print surface</p>
</td>
</tr>
<tr>
<td>✔ High temperature-resistance</td>
<td>
<p>✖ Soluble in dangerous chemicals</p>
</td>
</tr>
<tr>
<td>✔ Water and humidity resistant</td>
<td>
<p>✖ Supports are hard to remove</p>
</td>
</tr>
</tbody>
</table>
<h3>Best use</h3>
<p>PETG is used universally but is especially suitable for mechanical parts for both indoor and outdoor use. We use PETG to print parts for our printers! Plastic bottles are also made from this kind of material.</p>
<h3>Tips for successful printing</h3>
<p><strong>Temperature settings and cooling</strong></p>
<p>Unlike PLA, <strong>PETG requires a heated bed (85 °C).</strong> Its bridging- and overhang-behavior is usually worse, plus it is prone to stringing. Stringing can be moderated with higher retractions and lower nozzle temperature, but we suggest <strong>using the PrusaSlicer profiles that should work fine.</strong> It’s important to <strong>cool the PETG print</strong> - this helps to keep the model detailed and prevents stringing and oozing. But if you want the model to be as tough as possible, try to turn off the print fan. Higher filament temperature improves merging between layers which leads to better mechanical resistance. Otherwise, we recommend printing the first few layers with the print fan off to prevent deformation, then with the fan running at half its power.</p>
<div class="warning-callout"><strong>Do not print on the smooth PEI sheet</strong> as the adhesion may be too strong!</div>
<p><strong>Print surface preparation</strong></p>
<p>Make sure the print surface is clean, as described in <a href="http://help.prusa3d.com/article/first-layer-issues_1804">our dedicated article</a>. It is advisable to use one of the <strong>powder-coated print sheets. Do not print on the smooth PEI sheet</strong> as the adhesion may be too strong! If you decide to use the smooth PEI sheet anyway, apply a glue stick on it before printing.</p>
<p><strong>Adding more perimeters for more solid parts</strong></p>
<p>If you want to print truly solid parts, <strong>try to increase the number of perimeters</strong> instead of adding more infill.</p>
<h3>Postprocessing</h3>
<p>PETG can be easily sanded both dry and wet.</p>
<p><strong>Dissolving PETG</strong></p>
<p><strong>Dissolving and smoothing PETG</strong> is possible only in a laboratory by skilled lab workers using <strong>dangerous chemicals</strong> (Dichloromethane).</p>
<h3>Sample prints</h3>
<table style="border-collapse: collapse; width: 100%; height: 954px;" border="0">
<tbody>
<tr style="height: 300px;">
<td style="width: 48.805%; height: 300px;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-1-1.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-1-1-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-1-1-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-1-1-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-1-1-768x768.jpg 768w" alt="" width="800" height="800"></td>
<td style="width: 48.805%; height: 300px;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-jet-black-1kg.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-jet-black-1kg-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-jet-black-1kg-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-jet-black-1kg-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-jet-black-1kg-768x768.jpg 768w" alt="" width="800" height="800"></td>
</tr>
<tr style="height: 18px;">
<td style="width: 48.805%; height: 18px; text-align: center;"><em>MMU (Multi-Material Unit)</em></td>
<td style="width: 48.805%; height: 18px; text-align: center;"><em>Electronics cover and other printer parts</em></td>
</tr>
<tr style="height: 300px;">
<td style="width: 48.805%; height: 300px;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-2.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-2-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-2-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-2-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-2-768x768.jpg 768w" alt="" width="800" height="800"></td>
<td style="width: 48.805%; height: 300px;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-3.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-3-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-3-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-3-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-3-768x768.jpg 768w" alt="" width="800" height="800"></td>
</tr>
<tr style="height: 18px;">
<td style="width: 48.805%; height: 18px; text-align: center;"><em>Ukulele</em></td>
<td style="width: 48.805%; height: 18px; text-align: center;"><em>Various mechanical parts</em></td>
</tr>
<tr style="height: 300px;">
<td style="width: 48.805%; height: 300px; text-align: center;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-1.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-1-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-1-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-1-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-1-768x768.jpg 768w" alt="" width="800" height="800"></td>
<td style="width: 48.805%; height: 300px; text-align: center;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-768x768.jpg 768w" alt="" width="800" height="800"></td>
</tr>
<tr style="height: 18px;">
<td style="width: 48.805%; height: 18px; text-align: center;"><em>Electronic parts</em></td>
<td style="width: 48.805%; height: 18px; text-align: center;"><em>Boxes and organizers</em></td>
</tr>
</tbody>
</table>


PETG

Original Prusa i3 MK3S/MK3S+ to MK3.5 upgrade

Assembly manuals

Basic calibration

Advanced calibration

All information you need to know to learn how to calibrate your 3D printer to achieve perfect prints.

Calibration

Printer description

Printer features

FAQs and other useful information you might be interested in before or after making your purchase at shop.prusa3d.com

General Information

Basic overview of your 3D printer and it's features, plus general Prusa Research info.

About your printer

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Material guide

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In this section, you can find material guides, printer troubleshooting and general info about using your printer.

Using the printer

Print Quality Troubleshooting

QR Error codes

Printer troubleshooting

Description of how to recognize and solve common problems, especially hardware and electronics related.

Troubleshooting

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Octoprint

Learn about different nozzles, Raspberry Pi connection, Octoprint and more.

3rd party accessories & Other projects

About PrusaSlicer

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Printer settings

Advanced features

The official documentation for the PrusaSlicer slicing software. From basic configuration to advanced settings like modifier meshes.

PrusaSlicer

1. Introduction

2. Parts check

3. Printer dissasembly

4. xBuddy assembly

5. xLCD & PSU assembly

6. Heatbed upgrade

7. Extruder upgrade

8. Preflight check

Manual changelog MK3.5 upgrade

Prusa Connect &amp; PrusaLink

<h3>What happened? </h3>
<p>During the configuration of <strong>Prusa Connect</strong> on the <strong>Original Prusa MINI/+</strong>, <strong>MK4/S</strong>, <strong>MK3.9/S, MK3.5/S</strong> or <strong>XL</strong> an error on this configuration can occur and the printer shows the message "<strong>Registration to Prusa Connect failed due to: ~</strong>". In place of <strong>~</strong>, a text with more details is shown, from the list below. Depending on the specific shown text, there are different causes and fixes. </p>
<p>Error name: Connect Registration Failed</p>
<p>Error code: #12401 (MINI), #13401 (MK4), #26401 (MK4S), #21401 (MK3.9), #23401 (MK3.5), #17401 (XL)</p>
<h4>DNS error</h4>
<p>The printer wasn't able to resolve the <strong>hostname</strong> of the Prusa Connect server into an IP address. The hostname is a unique label assigned to a device connected to a network. </p>
<ul>
<li>The printer is not connected to the network at all.</li>
<li>In case of a <strong>static</strong> configuration (non-DHCP), the <strong>DNS server</strong> is not configured or configured incorrectly.</li>
<li>The local DNS server is currently not working.</li>
<li>The Connect hostname is reconfigured to some that doesn't exist. For example, this can occur if loading a .ini file with an invalid configuration.</li>
</ul>
<h4>Refused</h4>
<p>It's not possible to reach the server on the network level, hence it is not possible to establish a TCP connection. The system is either not answering at all or actively refuses the connection. </p>
<ul>
<li>The internet connection is not working, or a firewall blocks the communication.</li>
<li>In the case of a <strong>static</strong> configuration (non-DHCP), the <strong>gateway </strong>(typically, this is the IP address of the router) is not configured or configured incorrectly. </li>
<li>The Connect server is under maintenance. </li>
<li>Too many TCP connections are open with the printer, for example in PrusaLink. </li>
</ul>
<h4>TLS error</h4>
<p>This message points to an error doing a <strong>SSL/TLS handshake</strong>. This handshake is the process to create a safe and encrypted connection. </p>
<ul>
<li>Time is not synchronized on the printer (MINI/+). The time synchronization occurs for each internet connection, through the <a href="http://help.prusa3d.com/article/ntp-server-mini_151132">NTP server</a>. It is possible this might take more time than initially expected, or rarely, that there might be issues with the server. </li>
<li>A restrictive firewall (for example but not limited to a corporate proxy firewall) may restrict an automatic access to the NTP server. In that case, it will be necessary to manually allow the printer to access the NTP server.</li>
<li>Something in the path is trying to tamper with the communication, for example but not limited to an attack. </li>
</ul>
<h4>Unauthorized</h4>
<p>The server claims that the printer is not authorized. The printer is not recognized as an Original Prusa. </p>
<h4>Server error</h4>
<p>The server is returning a <strong>500 Internal Server Error</strong> or similar. The issue is on the Connect side, and is expected to be fixed on its own. </p>
<h4>Internal error</h4>
<p>This error is caused by an issue related to the printer firmware. </p>
<h4>Network error</h4>
<p>Similar to the Refused error, but the connection dropped after it was initialized. </p>
<ul>
<li>Glitchy internet connection.</li>
<li>The <strong>latency</strong> to the Connect servers is too high. A geographic location is very far from our Connect servers can contribute to this cause.</li>
<li>The Connect server is temporarily down.</li>
</ul>
<h4>Protocol error</h4>
<p>The response from the server is not recognized.</p>
<ul>
<li>Bug on the server side. This cause is on our side and expected to be fixed on its own. </li>
<li>Too old firmware on the printer and it's no longer supported.</li>
<li>A misconfiguration from the <strong>.ini file</strong> loaded on the printer, connecting to something different than our Connect server.</li>
</ul>
<h3>How to fix it? </h3>
<h4>DNS error, Refused</h4>
<p>Ensure that the printer is connected to the internet. In case of a static (non-DHCP) connection, ensure the correct settings are there, or test a DHCP connection. Also, check the .ini configuration file, and in case, rewrite the file. </p>
<p>If the previous steps didn't fix the issue, attempt a <a href="http://help.prusa3d.com/article/factory-reset-mini_177516">factory reset</a>. </p>
<h4>TLS error</h4>
<p>Reattempt the Connect registration, after the printer is connected to the internet for a few more minutes. </p>
<p>If the previous step didn't fix the issue, double-check your network <strong>firewall</strong>. Some firewalls will need for the NTP server to be allowed manually. The specific steps will depend on your specific firewall, we recommend checking your firewall documentation. </p>
<h4>Unauthorized</h4>
<p>If your printer is not an Original Prusa printer, it cannot use our Prusa Connect service.</p>
<p>In case your printer is an Original Prusa, <a href="http://help.prusa3d.com/article/firmware-updating-mini-mini_124784"> re-flash or update its firmware</a>. </p>
<h4>Server error</h4>
<p>A server error indicates an issue from our side. The issue will be fixed on its own, try registering again to Prusa Connect later. </p>
<h4>Internal error</h4>
<p><a href="http://help.prusa3d.com/article/firmware-updating-mini-mini_124784">Re-flash or update the printer firmware</a>. If this does not solve the issue, take note if the printer might have other issues, even if not directly related. </p>
<h4>Network error</h4>
<p>Ensure that your internet connection is stable and not glitchy. To confirm whether an inconsistent internet connection caused the issue, test another connection, if available, such as a hotspot from your mobile phone. </p>
<h4>Protocol error</h4>
<p>Ensure that the printer is running our latest firmware version. If it is running an old version, update the firmware. Also, check the .ini configuration file, and in case, rewrite the file.</p>


Connect Registration Failed

<h3>What happened?</h3>
<p>The Original Prusa MK4S/MK4/MK3.9/MK3.5 displays the message: "<strong>Failed to home the extruder in X-axis, make sure there is no obstacle on X-axis</strong>".</p>
<p>Error name: Homing error X</p>
<p>Error code: #26304 (MK4S) #13304 (MK4) #21304 (MK3.9) #23304 (MK3.5)</p>
<p>The error is most likely caused by a bad movement of the print head along the X-axis. </p>
<h3>How to fix it? </h3>
<h4>X-axis movement</h4>
<p>Make sure there are no obstructions in the path of the X-axis. For example, there might be a piece of filament stuck around the belt, or on a smooth rod, from a previous print.</p>
<h4>X-axis belt tension</h4>
<p>Check the X-axis belt tension and adjust it, following our <a href="http://help.prusa3d.com/article/adjusting-belt-tension-mk4-s-mk3-9-s-mk3-5-s-mk3-s_112380">dedicated article on belt adjustment</a>.</p>
<h4>X-axis motor pulley</h4>
<p>The X-axis motor pulley is attached to the X-axis motor shaft. The motor shaft has one flat side. The pulley has two set screws: ensure that one of the two set screws is aligned with the flat part of the motor shaft. Make sure the other set screw is also tightened, not excessively, and that there is a small space between the pulley and the motor. </p>
<h4>X-carriage assembly</h4>
<p>An over-tightened or loose X-carriage and X-carriage-clip assembly might cause the error. If none of the previous steps resolved the issue, refer to our <a href="http://help.prusa3d.com/guide/3-x-axis-x-carriage-assembly_429986">assembly manual</a> to see the assembly of the X-carriage and X-carriage-clip.</p>
<h4>xBuddy connection</h4>
<p>Check the motor connections on the board. For that, open the four screws that hold the xBuddy box cover. Make sure that the motor connector is not loose, and that the X-axis motor connector has not been accidentally switched with the Y-axis motor or any other motor.</p>
<table style="border-collapse: collapse; width: 100.026%;" border="0">
<tbody>
<tr>
<td style="width: 48.7906%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/10/9769d45d75346583db549d162dbb302b_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Homing error Y #13305 (MK4) #21305 (MK3.9)" alt="" width="400" height="300" loading="lazy" /></td>
<td style="width: 48.7906%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/10/a5df42079c5152c4bb1404adc18106ea.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Homing error Y #13305 (MK4) #21305 (MK3.9)" alt="" width="400" height="300" loading="lazy" /></td>
</tr>
</tbody>
</table>


Homing error X #26304 (MK4S) #13304 (MK4) #21304 (MK3.9) #23304 (MK3.5)

<h3>What happened?</h3>
<p>The Original Prusa MK4S/MK4/MK3.9/MK3.5 displays the message: <strong>"Failed to home the Y-axis, make sure there is no obstacle on Y-axis</strong>".</p>
<p>Error name: Homing error Y</p>
<p>Error code: #26305 (MK4S) #13305 (MK4) #21305 (MK3.9) #23305 (MK3.5)</p>
<p>The error is most likely caused by a bad movement of the Y-carriage along the Y-axis.</p>
<h3>How to fix it? </h3>
<h4>Y-axis movement</h4>
<p>Make sure there are no obstructions in the path of the Y-axis. For example, there might be a piece of filament stuck around the belt, or on a smooth rod, from a previous print.</p>
<h4>Y-axis belt tension</h4>
<p>Check the Y-axis belt tension and adjust it, following our <a href="http://help.prusa3d.com/article/adjusting-belt-tension-mk4-s-mk3-9-s-mk3-5-s-mk3-s_112380">dedicated article on belt adjustment</a>.</p>
<h4>Y-axis motor pulley</h4>
<p>The Y-axis motor pulley is attached to the Y-axis motor shaft. The motor shaft has one flat side. The pulley has two set screws, ensure that one of the two set screws is aligned with the flat part of the motor shaft. Make sure the other set screw is also tightened, not excessively, and that there is a small space between the pulley and the motor.</p>
<h4>Y-axis bearings position</h4>
<p>Incorrect positioning of the bearings might cause the error.</p>
<p>On the side of the Y-carriage with one bearing, ensure that the bearing is centered on the bearing clip. Approximately the same piece of bearing should be visible on each side.</p>
<p>On the side of the Y-carriage with two bearings, place the bearings as close to the center of the Y-carriage as possible. Beware, the bearings must not touch the edge of the pocket!</p>
<table style="border-collapse: collapse; width: 100%; height: 21px;" border="0">
<tbody>
<tr style="height: 21px;">
<td style="width: 48.8358%; height: 21px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/06/00caa1b4b7e7f0e52a2652767a228c72_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="USB Port overcurrent #13306 (FIONA)" alt="" width="400" height="300" loading="lazy" /></td>
<td style="width: 48.8358%; height: 21px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/06/0f85fe99ce29ae9b2d2b9b17eeb6481d_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="USB Port overcurrent #13306 (FIONA)" alt="" width="399" height="299" loading="lazy" /></td>
</tr>
</tbody>
</table>
<p>If you are correcting the position of the bearings, make sure to keep the correct orientation. The tracks (rows of balls) have to be on the sides.</p>
<table style="border-collapse: collapse; width: 100%; height: 21px;" border="0">
<tbody>
<tr style="height: 21px;">
<td style="width: 48.8358%; height: 21px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/06/072a3e6a00466141e3159d45a529cf33_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="USB Port overcurrent #13306 (FIONA)" alt="" width="400" height="300" loading="lazy" /></td>
<td style="width: 48.8358%; height: 21px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/06/6fbbf29a7f039d5a3ab1b2f2ebec8ec0_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="USB Port overcurrent #13306 (FIONA)" alt="" width="399" height="299" loading="lazy" /></td>
</tr>
</tbody>
</table>
<h4>xBuddy connection</h4>
<p>Check the motor connections on the board. For that, open the four screws that hold the xBuddy box cover. Make sure that the motor connector is not loose, and that the Y-axis motor connector has not been accidentally switched with the X-axis motor or any other motor.</p>
<table style="border-collapse: collapse; width: 100.026%;" border="0">
<tbody>
<tr>
<td style="width: 48.7906%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/10/9769d45d75346583db549d162dbb302b_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Homing error Y #13305 (MK4) #21305 (MK3.9)" alt="" width="400" height="300" loading="lazy" /></td>
<td style="width: 48.7906%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/10/a5df42079c5152c4bb1404adc18106ea.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Homing error Y #13305 (MK4) #21305 (MK3.9)" alt="" width="400" height="300" loading="lazy" /></td>
</tr>
</tbody>
</table>


Homing error Y #26305 (MK4S) #13305 (MK4) #21305 (MK3.9) #23305 (MK3.5)

<h3>What happened?</h3>
<p>The printer is showing the message <strong>"Check the heatbed heater &amp; thermistor wiring for possible damage."</strong></p>
<p>Error name: Bed preheat error</p>
<p>Error code: #26201 (MK4S) #13201 (MK4) #21201 (MK3.9) #23201 (MK3.5)</p>
<p>This message is shown when, during the preheat, the printer does not increase more than <strong>2 ºC for 20 seconds</strong>. The heating is paused so the issue can be fixed.</p>
<h3>How to fix it?</h3>
<p>Make sure that the <strong>ambient temperature</strong> where the printer is is stable, and above <strong>10 ºC</strong>.</p>
<p>This error can be caused by damage to either the <strong>heatbed thermistor</strong> or the <strong>heatbed power cable</strong>.</p>
<div class="tip-callout">Doing <strong>regular maintenance</strong> on the printer may prevent this type of issue.</div>
<p>On the heatbed, check the following:</p>
<ul>
<li>See if the <strong>thermistor </strong>is firmly seated below the <strong>Golden Kapton tape.</strong></li>
<li>Make sure that the <strong>washer </strong>is screwed above the round cable connector, not below it.</li>
<li>Check if the <strong>M3nN nut</strong> is holding the screw firmly.</li>
<li>Access the xBuddy board. Check the <strong><span style="color: #236fa1;">heatbed power cable</span></strong>, the <strong><span style="color: #2dc26b;">heatbed thermistor</span></strong>, and the <a href="http://help.prusa3d.com/article/blown-fuse-mk4-s-mk3-9-s_411666">fuse that protects the heatbed</a>.</li>
</ul>
<table style="border-collapse: collapse; width: 100%; height: 322.875px;" border="0">
<tbody>
<tr style="height: 301.875px;">
<td style="width: 48.8358%; height: 301.875px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/Heatbedthermistor.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Preheat error #13201 (FIONA)" alt="" width="400" height="300" loading="lazy" /></td>
<td style="width: 48.8358%; height: 301.875px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/b219085ec996c508.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Preheat error #13201 (FIONA)" alt="" width="400" height="300" loading="lazy" /></td>
</tr>
<tr style="height: 21px;">
<td style="width: 48.8358%; height: 21px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/30e875e9b027e87d.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Preheat error #13201 (FIONA)" alt="" width="400" height="1200" loading="lazy" /></td>
<td style="width: 48.8358%; height: 21px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/77686da340e7e4a3_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Preheat error #13201 (FIONA)" alt="" width="400" /></td>
</tr>
</tbody>
</table>
<p>In case all the items are correct, there might be an internal break in one of the cables. If you do not have a multimeter, it is possible to check the cables using the following test: </p>
<ol>
<li>Use a hairdryer to blow hot air at the heatbed.</li>
<li>While doing that, check if there is any temperature change on the LCD screen.</li>
<li>If there is a positive temperature change it means that the heatbed thermistor is working. In this case, the heater is defective.</li>
<li>If there is no change at all, the heatbed thermistor is defective.</li>
</ol>
<h4>Multimeter check</h4>
<p>In case you have a multimeter available, it is possible to check the resistance of the cables using the <a href="http://help.prusa3d.com/article/multimeter-usage_2117">Multimeter usage</a> guide.</p>


Bed preheat error #26201 (MK4S) #13201 (MK4) #21201 (MK3.9) #23201 (MK3.5)

<h3>What happened?</h3>
<p>The Original Prusa MK4S/MK4/MK3.9/MK3.5 is equipped with a <strong>Power Panic</strong> feature. This feature can recover a print in case of a sudden power loss (read more about it <a href="http://help.prusa3d.com/article/power-panic_2092">here</a>). The power panic cable goes from the printer's PSU to the xBuddy board. In case there is any damage to the cable, the printer will show <strong>"Power panic has been detected during printer initialization. Inspect wiring of PP-cable."</strong></p>
<p>Error name: Power Panic</p>
<p>Error code: #26321 (MK4S) #13321 (MK4)  #20321 (MK3.9) #23321 (MK3.5)</p>
<h3>How to fix it?</h3>
<p>Check the connection of the cable both on the PSU and on the xBuddy board. Make sure that the cable is not damaged.</p>
<div class="note-callout">There are two versions of the power panic cable, one with only a black wire and one with black and white wires. Both are compatible with the MK4/S, MK3.9, and MK3.5, and there is no need to switch to one or the other.</div>
<div>
<table style="border-collapse: collapse; width: 100%; border-style: none;" border="0">
<tbody>
<tr>
<td style="width: 48.7906%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/08/3511cecf57c9cc5b14c140cd32c0bdee_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Power Panic #13321 (MK4)" alt="" width="395" height="296" loading="lazy" /></td>
<td style="width: 48.7906%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/08/1566eaf9ab8a2344560a6516c71d2673_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Power Panic #13321 (MK4)" alt="" width="395" height="1138" loading="lazy" /></td>
</tr>
</tbody>
</table>
</div>


Power Panic #26321 (MK4S) #13321 (MK4)  #21321 (MK3.9) #23321 (MK3.5)

<h3>What happened?</h3>
<p>The Original Prusa MK4/MK3.9/MK3.5 is showing the message: <strong>"Overcurrent detected on xBuddy heatbed port, disconnect the device."</strong></p>
<p>Error name: Heatbed Port Overcurrent</p>
<p>Error code: #26309 (MK4S) #13309 (MK4) #21309 (MK3.9) #23309 (MK3.5)</p>
<p>The error is shown when there is a damaged cable on the <strong>heatbed </strong>or any of its connections.</p>
<h3>How to fix it? </h3>
<p>The most likely cause of this issue is damage to the <strong>heatbed </strong>cable. Check the path between the heatbed and the <strong>xBuddy </strong>board, and see if there are any parts that are broken or pinched.</p>
<p>In case there is no damage, check the cable connection to the heatbed and to the xBuddy board. Try reconnecting the connectors.</p>
<p>In rare cases, this error message can be shown in case of damage to the xBuddy board. So if the cables and connectors are intact, try checking the board for any damage.</p>
<table style="border-collapse: collapse; width: 100%; height: 21px;" border="0">
<tbody>
<tr style="height: 21px;">
<td style="width: 48.8358%; height: 21px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/5bf0be529c827b33.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="USB Port overcurrent #13306 (FIONA)" alt="" width="400" height="300" loading="lazy" /></td>
<td style="width: 48.8358%; height: 21px;"> <img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/ca06837a757f0023_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Heatbed Port Overcurrent #13309 (FIONA)" alt="" width="399" height="299" loading="lazy" /></td>
</tr>
</tbody>
</table>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/a325d581e1a553bd_painted.jpeg" alt="" width="400" height="275" loading="lazy" /></p>


Heatbed Port Overcurrent #26309 (MK4S) #13309 (MK4) #21309 (MK3.9) #23309 (MK3.5)

<h3>What happened?</h3>
<p>The <strong>MK4S/MK4/MK3.9/MK3.5 xBuddy board</strong> is equipped with a safety mechanism to detect power supply overcurrent situations in the connection to the Multi-material unit (MMU). Upon detecting overcurrent, the printer automatically cuts off both power and communication to the MMU unit as a preventive measure against damage.</p>
<h3>I don't have an MMU installed</h3>
<p>If you haven't installed an MMU, make sure to disable the MMU functionality in the printer's menu in Settings -&gt; MMU Enable. However, if you still face this issue with the MMU option being turned off, it might indicate a damaged component on the xBuddy board. Please reach out to <a href="http://help.prusa3d.com/article/customer-support_2287">Customer support</a> for assistance.</p>
<h3>How to fix it?</h3>
<div class="note-callout">The MMU unit should not be connected or disconnected during regular use while the printer is running.</div>
<p>Inspect the <strong>MMU, Printer cable, and PD board</strong> for any signs of damage. Check the cable's path to the xBuddy board for any broken or pinched parts.</p>
<p>If there's no visible damage, ensure the cable connections to the MMU PDU and the xBuddy board are secure.</p>
<p>To troubleshoot, first disconnect the <strong><span style="color: #f1c40f;">MMU cable</span></strong> from the xBuddy board, go to the printer menu in <em>Settings -&gt; MMU Enable</em> and set the MMU to off. Verify if the printer operates correctly with the MMU unit disconnected and the MMU functionality turned off. After confirming this, reconnect the MMU and test the printer with the MMU turned on.</p>
<p>In rare cases, this error message might be shown due to a damaged xBuddy board. Try checking the board for any signs of damage.</p>
<div class="note-callout">When contacting <a href="http://help.prusa3d.com/article/customer-support_2287">Customer support</a> about this issue, it's crucial to specify not only what firmware and hardware are you using, but also the <strong>version of your printer's xBuddy board</strong> (e.g., 0.2.7 / v36, etc.), as there are variations in the electronic diagrams across different versions.</div>
<table style="border-collapse: collapse; width: 100%; height: 21px;" border="0">
<tbody>
<tr style="height: 21px;">
<td style="width: 50%; height: 21px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/02/14f3801e133f167c644feea2d7e8a601_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="MMU / Printer cable connected to the MMU3’s PD-board addon on the control board." alt="" width="1600" height="1200" loading="lazy" /></td>
<td style="width: 50%; height: 21px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/02/682bd0e96557fd37c8514dde88f4cc4a_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="MMU Overcurrent #13310 (MK4) #21310 (MK3.9)" alt="" width="400" height="300" loading="lazy" /></td>
</tr>
</tbody>
</table>
<h3>Technical information</h3>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/02/80b81dcc74f145ce57f9615b9accb7c6.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="MMU Overcurrent #13310 (MK4) #21310 (MK3.9)" alt="" width="600" height="373" loading="lazy" /></p>
<p>The xBuddy board is constantly monitoring the current flowing through the electronics. If the power draw exceeds 3.6A on the MMU connector's power line, the printer will display this error, and the corresponding LED indicator on the xBuddy board will illuminate. A potential overcurrent condition is likely to occur after the first startup, as power demand peaks while capacitors are charging. </p>
<p>The xBuddy board is designed with the capability to fully manage power delivery to the MMU unit, incorporating a software feature to mitigate such overcurrent scenarios. However, this function is specifically calibrated for the original MMU3 unit. In certain unsupported hardware configurations, this may result in a false error indication.</p>


MMU Overcurrent #26310 (MK4S) #13310 (MK4) #21310 (MK3.9) #23310 (MK3.5)

<h3>What happened?</h3>
<p>On the Original Prusa MK4/MK3.9/MK3.5, the I2C bus is used for the <strong>xBuddy</strong> board to communicate with other printer components. If there is an error in sending data from the xBuddy board, the printer will show the message: <strong>"HAL detected an I2C error when sending data via I2C."</strong></p>
<p>Error name: I2C Send failed</p>
<p>Error code: #26311 (MK4S) #13311 (MK4) #21311 (MK3.9) #23311 (MK3.5)</p>
<h3>How to fix it? </h3>
<p><strong>Restarting the printer</strong> is expected to resolve the error, and this is not expected to occur again. In case a restart does not resolve it, please contact our <a href="http://help.prusa3d.com/article/customer-support_2287">customer support</a>, we will take it from here. </p>


I2C Send failed #26311 (MK4S) #13311 (MK4) #21311 (MK3.9) #23311 (MK3.5)

<h3>What happened?</h3>
<p>The printer is showing the message <strong>"Check the heatbed thermistor wiring for possible damage."</strong></p>
<p>Error name: Bed thermal runaway </p>
<p>Error code: #26203 (MK4S) #13203 (MK4) #21203 (MK3.9) #23203 (MK3.5)</p>
<p><strong>Thermal Runaway</strong> is a safety feature designed to cut power to the heaters in case of a cable malfunction. If your printer's thermistor somehow dislodges itself, electronic parts can get a lower (incorrect) temperature reading. In an attempt to compensate for the lower temperature, the heater could reach dangerously high temperatures.</p>
<p>If the <strong>heatbed </strong>temperature drops by more than <strong>2 ºC</strong> for over<strong> 60 seconds</strong>, the printer will shut down the print and show the Thermal Runaway error.</p>
<h3>How to fix it?</h3>
<p>Make sure that the ambient temperature is above <strong>10 ºC</strong>, and that there are <strong>no sources of cooling</strong> near the printer, like air conditioning or windows.</p>
<p>Check if the thermistor is well secured under the <strong>golden Kapton tape</strong>.</p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/Heatbedthermistor.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Thermal runaway #13203 (FIONA)" alt="" width="600" height="450" loading="lazy" /></p>
<p>If you are printing small objects with high-temperature filaments, try to print multiple at once and/or place them away from the center of the heatbed.</p>
<p>Open the <strong>xBuddyBox-cover</strong> and the <strong>el-box-cover</strong> by opening the screws indicated below to access the heatbed cables. Make sure that the heatbed power cable did not slip from the screw, and that the heatbed thermistor cable is well connected.</p>
<p>If you have a multimeter, you can check the resistance of the cables using this guide: <a href="http://help.prusa3d.com/article/multimeter-usage_2117">Multimeter usage</a>.</p>
<table style="border-collapse: collapse; width: 100%;" border="0">
<tbody>
<tr>
<td style="width: 48.8358%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/ef0adcc4ba6782d2_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Thermal runaway #13203 (FIONA)" alt="" width="400" height="267" loading="lazy" /></td>
<td style="width: 48.8358%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/783109cb80ab5ceb_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Thermal runaway #13203 (FIONA)" alt="" width="400" height="267" loading="lazy" /></td>
</tr>
</tbody>
</table>
<h3> </h3>


Bed thermal runaway #26203 (MK4S) #13203 (MK4) #21203 (MK3.9) #23203 (MK3.5)

<h3>What happened?</h3>
<p>On the Original Prusa MK4S/MK4/MK3.9/MK3.5, the I2C bus is used for the <strong>xBuddy</strong> board to communicate with other printer components. If there is an error while the xBuddy board is receiving data, the printer will show the message: <strong>"HAL detected an I2C error when receiving data via I2C."</strong></p>
<p>Error name: I2C Receive Failed</p>
<p>Error code: #26315 (MK4S) #13315 (MK4) #21315 (MK3.9) #23315 (MK3.5)</p>
<h3>How to fix it? </h3>
<p><strong>Restarting the printer</strong> is expected to resolve the error, and this is not expected to occur again. In case a restart does not resolve it, please contact our <a href="http://help.prusa3d.com/article/customer-support_2287">customer support</a>, we will take it from here. </p>


I2C Receive Failed #26315 (MK4S) #13315 (MK4) #21315 (MK3.9) #23315 (MK3.5)

<h3>What happened?</h3>
<p>The printer is showing  the message <strong>"Check the heatbed thermistor wiring for possible damage."</strong></p>
<p>Error name: Bed mintemp error </p>
<p>Error code: #26207 (MK4S) #13207 (MK4) #21207 (MK3.9) #23207 (MK3.5)</p>
<p>This error is shown when the heatbed temperature drops below <strong>5 ºC</strong> at any time. This error can also happen when the printer is idle and not heated.</p>
<h3>How to fix it?</h3>
<p>Make sure that the <strong>ambient temperature</strong> where the printer is is stable, and above <strong>10 ºC</strong>.</p>
<p>This error is usually caused by a damaged <strong>heatbed thermistor</strong>.</p>
<div class="tip-callout">Doing regular maintenance on the printer may prevent this type of issue.</div>
<p>Check if the thermistor is well secured under the <strong>golden Kapton tape</strong>.</p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/Heatbedthermistor.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Maxtemp error #13205 (FIONA)" alt="" width="500" height="375" loading="lazy" /></p>
<p>In order to test if the thermistor is damaged, go to the printer menu in <em>Settings -&gt; Temperature -&gt; Heatbed temperature</em>, and set it to <strong>80 ºC</strong>. Then, move the heatbed cables by hand and see if the temperature will fluctuate. If the temperature fluctuates more than <strong>5 ºC</strong>, from the set temperature, the thermistor needs to be replaced.</p>
<p>Open the <strong>xBuddyBox-cover</strong> and the <strong>el-box-cover</strong> by opening the screws indicated below to access the heatbed cable connectors. Make sure that the heatbed power cable did not slip from the screw, and that the heatbed thermistor cable is well connected.</p>
<p>If you have a <strong>multimeter</strong>, you can check the resistance of the cables using this guide: <a href="http://help.prusa3d.com/article/multimeter-usage_2117">Multimeter usage</a></p>
<table style="border-collapse: collapse; width: 100%;" border="0">
<tbody>
<tr>
<td style="width: 48.8358%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/ef0adcc4ba6782d2_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Thermal runaway #13203 (FIONA)" alt="" width="400" height="267" loading="lazy" /></td>
<td style="width: 48.8358%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/783109cb80ab5ceb_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Thermal runaway #13203 (FIONA)" alt="" width="400" height="267" loading="lazy" /></td>
</tr>
</tbody>
</table>
<h3> </h3>


Bed mintemp error #26207 (MK4S) #13207 (MK4) #21207 (MK3.9) #23207 (MK3.5)

<h3>What happened?</h3>
<p>When flashing the firmware on your Original Prusa MK4, MK3.9, or MK3.5, you might get the message "<strong>Firmware file missing in the USB flash!</strong>".</p>
<p>Error name: No FW on USB flash drive</p>
<p>Error code: #26604 (MK4S) #13604 (MK4) #21604 (MK3.9) #23604 (MK3.5)</p>
<p>This error happens when you attempt flashing firmware on the printer, but the printer does not find any firmware in the USB drive that can be uploaded to the printer.</p>
<h3>How to fix it?</h3>
<p><a href="https://help.prusa3d.com/downloads">Download the firmware</a> and if necessary the bootloader, and transfer it to your USB drive. Make sure to unmount the drive from your operating system before physically removing it.</p>
<p>Insert the USB drive back into the printer and reboot the printer using the reset button directly next to the knob to initiate the flashing procedure. In case the procedure does not start, reboot the printer again by pressing the same reset button, and while the printer is booting up, press once the rotating knob.</p>
<p>If the issue persists, the problem might be in the USB flash drive. Find any other USB drive in your household, make sure it is formatted to FAT32, copy both firmware files and repeat the previously described procedure.</p>
<div class="tip-callout">Are you still having issues? Contact our <a href="http://help.prusa3d.com/article/customer-support_2287">support team</a> and let them know that you tried to fix the issue with these instructions. We will take it from there.</div>


No FW on USB #26604 (MK4S) #13604 (MK4) #21604 (MK3.9) #23604 (MK3.5)

<h3>What happened?</h3>
<p>During firmware flashing on your Original Prusa MK4, MK3.9, or MK3.5, you might get the message "<strong>USB drive not connected! Please insert a USB drive with a valid firmware file</strong>".</p>
<p>Error name: USB not connected</p>
<p>Error code: #26602 (MK4S) #13602 (MK4) #21602 (MK3.9) #23602 (MK3.5)</p>
<p>This issue happens when there is an error reading the USB drive.</p>
<h3>How to fix it?</h3>
<p>Make sure that the USB drive is connected to the printer, and that the USB port in the mainboard is not damaged. If the error persists, try using a new, <a href="https://help.prusa3d.com/article/sd-cards-and-usb-drives_112291#how-do-i-format-the-usb-drive-sd-card" target="_blank" rel="noopener">FAT32-formatted USB drive</a>. </p>
<div class="tip-callout">Are you still having issues? Contact our <a href="http://help.prusa3d.com/article/customer-support_2287">support team</a> and let them know that you tried to fix the issue with these instructions. We will take it from there.</div>


USB not connected #26602 (MK4S) #13602 (MK4) #21602 (MK3.9) #23602 (MK3.5)

<h3>What happened?</h3>
<p>The Original Prusa MK4/S, MK3.9, and MK3.5 are equipped with the xBuddy board. Thanks to this, and the capability for firmware to check for the connected components, the printer can detect a firmware installed for the wrong printer version.</p>
<p>In case the printer recognizes a wrong firmware version is installed, it shows the message "<strong>To continue, please insert the bundled USB flash drive and install the MK4/MK3.9/MK3.5 firmware</strong>", with just the detected printer model shown in the message. </p>
<p>Error name: Different FW Required</p>
<p>Error code: #26701 (MK4S) #13701 (MK4) #21701 (MK3.9) #23701 (MK3.5)</p>
<h3>How to fix it?</h3>
<p>Download the firmware, and ensure the version is compatible with your printer model.</p>
<ul>
<li><a href="https://help.prusa3d.com/downloads/mk4s/firmware">Original Prusa MK4S</a></li>
<li><a href="https://help.prusa3d.com/downloads/mk4/firmware">Original Prusa MK4</a></li>
<li><a href="https://help.prusa3d.com/downloads/mk3-9/firmware">Original Prusa MK3.9</a></li>
<li><a href="https://help.prusa3d.com/downloads/mk3-5/firmware">Original Prusa MK3.5</a></li>
</ul>
<p>Transfer the firmware file to your USB drive. Make sure to unmount the drive from your operating system before physically removing it. Then, follow the procedure for firmware flashing.</p>
<div class="tip-callout">Are you still having issues? Contact our <a href="http://help.prusa3d.com/article/customer-support_2287">support team</a> and let them know that you tried to fix the issue with these instructions. We will take it from there.</div>


Firmware Update Required #26701 (MK4S) #13701 (MK4) #21701 (MK3.9) #23701 (MK3.5)

<h3>What happened?</h3>
<p>The printer is showing the message <strong>"Reading ESP firmware failed."</strong></p>
<p>Error name: ESP Error</p>
<p>Error code: #26504 (MK4S) #13504 (MK4) #21504 (MK3.9) #23504 (MK3.5)</p>
<p>On the Original Prusa MK4/MK3.9/MK3.5, the <strong>xBuddy </strong>board can be extended with a Wi-Fi module. The error is triggered when the xBuddy does not correctly find or read the firmware installed on the Wi-Fi module, needed to achieve Wi-Fi connectivity. </p>
<h3>How to fix it?</h3>
<h4>Re-flash firmware</h4>
<p>The firmware needed for the Wi-Fi module is included in the MK4S/MK4/MK3.9/MK3.5 firmware file. <a href="https://help.prusa3d.com/downloads">Download the firmware</a> and if necessary the bootloader, and transfer it to your USB drive. Make sure to unmount the drive from your operating system before physically removing it.</p>
<p>Insert the USB drive back into the printer and reboot the printer using the reset button directly next to the knob to initiate the flashing procedure. In case the procedure does not start, reboot the printer again by pressing the same reset button, and while the printer is booting up, press once the rotating knob.</p>
<p>The printer will let you know when the flashing is done. When installing the bootloader along with the firmware, it may take several minutes.</p>
<h4>A visual inspection</h4>
<div class="warning-callout">Before accessing any of the electronic boards, ensure that the printer is <strong>fully cooled down</strong>, and <strong>switched off for at least 10 minutes</strong>. </div>
<p>Access the xBuddy board by loosening the four screws in the below picture, and inspect it for any visible damage. </p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/04/754b36a4adbfe826a6b9387094c2c9f4_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="ESP Error #13504 (FIONA)" alt="" width="600" height="450" loading="lazy" /></p>
<div class="tip-callout">Are you still having issues? Contact our <a href="http://help.prusa3d.com/article/customer-support_2287">support team</a> and let them know that you tried to fix the issue with these instructions. We will take it from there.</div>


ESP Error #26504 (MK4S) #13504 (MK4) #21504 (MK3.9) #23504 (MK3.5)

<h3>What happened?</h3>
<p>When trying to flash the firmware on your Original Prusa MK4, MK3.9, or MK3.5, the printer shows the error: "<strong>Firmware in the internal flash corrupted! Please reflash the firmware.</strong>"</p>
<p>Error name: FW in internal flash corrupted</p>
<p>Error code: #26608 (MK4S) #13608 (MK4) #21608 (MK3.9) #23608 (MK3.5)</p>
<p>This error is shown when the firmware file in the internal flash is damaged, causing the firmware flashing procedure to fail.</p>
<h3>How to fix it?</h3>
<p><a href="https://help.prusa3d.com/downloads" target="_blank" rel="noopener">Download the firmware</a> and if necessary the bootloader, and transfer it to your USB drive. Make sure to unmount the drive from your operating system before physically removing it.</p>
<p>Insert the USB drive back into the printer and reboot the printer using the reset button directly next to the knob to initiate the flashing procedure. In case the procedure does not start, reboot the printer again by pressing the same reset button, and while the printer is booting up, press once the rotating knob.</p>
<p>If the issue persists, the problem might be in the USB flash drive. Find any other USB drive in your household, make sure it is formatted to FAT32, copy both firmware files, and repeat the previously described procedure.</p>
<div class="tip-callout">Are you still having issues? Contact our <a href="http://help.prusa3d.com/article/customer-support_2287">support team</a> and let them know that you tried to fix the issue with these instructions. We will take it from there.</div>


FW in internal flash corrupted #26608 (MK4S) #13608 (MK4) #21608 (MK3.9) #23608 (MK3.5)

<h3>What happened?</h3>
<p>The printer is showing the error <strong>"Check the heatbed thermistor wiring for possible damage."</strong></p>
<p>Error name: Bed Maxtemp error </p>
<p>Error code: #26205 (MK4S) #13205 (MK4) #21205 (MK3.9) #23205 (MK3.5)</p>
<p>The error happens when the printer's heatbed temperature goes above <strong>125 ºC</strong> at any point. This is a safety feature to prevent printer damage. In this case, the printer will stop the heating and display the message on the screen.</p>
<h3>How to fix it?</h3>
<p>Make sure that the <strong>ambient temperature</strong> where the printer is is stable, and above <strong>10 ºC</strong>.</p>
<p>This error is usually caused by a damaged <strong>heatbed thermistor</strong>.</p>
<div class="tip-callout">Doing regular maintenance on the printer may prevent this type of issue.</div>
<p>Check if the thermistor is well secured under the <strong>golden Kapton tape</strong>.</p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/Heatbedthermistor.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Maxtemp error #13205 (FIONA)" alt="" width="500" height="375" loading="lazy" /></p>
<p>In order to test if the thermistor is damaged, go to the printer menu in <em>Settings -&gt; Temperature -&gt; Heatbed temperature</em>, and set it to <strong>80 ºC</strong>. Then, move the heabed cables by hand and see if the temperature will fluctuate. If the temperature fluctuates more than <strong>5 ºC</strong>, from the set temperature, the thermistor needs to be replaced.</p>
<p>Open the <strong>xBuddyBox-cover</strong> and the <strong>el-box-cover</strong> by opening the screws indicated below to access the heatbed cable connectors. Make sure that the heatbed power cable did not slip from the screw, and that the heatbed thermistor cable is well connected.</p>
<p>If you have a <strong>multimeter</strong>, you can check the resistance of the cables using this guide: <a href="http://help.prusa3d.com/article/multimeter-usage_2117">Multimeter usage</a></p>
<table style="border-collapse: collapse; width: 100%;" border="0">
<tbody>
<tr>
<td style="width: 48.8358%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/ef0adcc4ba6782d2_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Thermal runaway #13203 (FIONA)" alt="" width="400" height="267" loading="lazy" /></td>
<td style="width: 48.8358%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/783109cb80ab5ceb_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Thermal runaway #13203 (FIONA)" alt="" width="400" height="267" loading="lazy" /></td>
</tr>
</tbody>
</table>
<h3> </h3>


Bed maxtemp error #26205 (MK4S) #13205 (MK4) #21205 (MK3.9) #23205 (MK3.5)

<h3>What happened? </h3>
<p>During the configuration of <strong>Prusa Connect</strong> on the <strong>Original Prusa MK3.5</strong>, an error on this configuration can occur and the printer shows the message "<strong>Registration to Prusa Connect failed due to: ~</strong>". In place of ~, a text with more details is shown. </p>
<p>Error name: Connect Registration Failed</p>
<p>Error code: #23401</p>
<h3>How to fix it? </h3>
<p>Follow the instructions in the <a href="http://help.prusa3d.com/article/connect-registration-failed_654926">Connect Registration Failed guidepost</a>, common to our printers with Buddy firmware, with more details on possible causes for this error and their solutions. </p>


Connect Registration Failed #23401 (MK3.5)

<h3>What happened?</h3>
<p>The printer is showing the message "<strong>Hotend preheat error: Check the print head heater and thermistor wiring for potential damage</strong>"</p>
<p>Error name: Hotend preheat error</p>
<p>Error code: #23202</p>
<p>This error is shown when the printer is unable to heat up the nozzle more than <strong>2 ºC for 20 seconds</strong>. The printer starts a safety feature, which instantly kills the heating process and displays the message on the screen. The printer then waits for the user to inspect all parts and if needed fix the issue.</p>
<h3>How to fix it?</h3>
<ol>
<li>Make sure that the <strong>ambient temperature</strong> where the printer is stable, and above <strong>10 ºC</strong>.</li>
<li>Make sure the thermistor and heater are properly plugged into the electronics board. You can double-check that by following this guide: (link from assembly guide)</li>
<li>Check if the <a href="http://help.prusa3d.com/article/blown-fuse-mk4-s-mk3-9-s_411666">fuses</a> are not blown. </li>
<li>Make sure that your <a href="http://help.prusa3d.com/guide/how-to-replace-a-heatbreak-heatsink-heaterblock-mk3s-mk3s-mk2-5s-mmu2s_16104#17312">hotend assembly</a> is correct.</li>
</ol>
<table style="border-collapse: collapse; width: 100%; border-style: hidden;" border="1">
<tbody>
<tr>
<td style="width: 48.8562%;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/Iks4qr6BGKs1BVQJ.jpg" alt="" width="395" height="296" /></td>
<td style="width: 48.8562%;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusuki/prusuki-images/OSuV4Jxg36M4LU1I.jpg" alt="" width="395" height="296" /></td>
</tr>
</tbody>
</table>
<p>If the issue persists, the error likely stemmed from an issue with the hotend heater or hotend thermistor. To find out which one of these two is malfunctioning, perform the test described below.</p>
<div class="tip-callout">You can also verify if the thermistor or heater is damaged using a <a href="http://help.prusa3d.com/article/multimeter-usage_2117">multimeter</a>.</div>
<p>Use a hairdryer to blow hot air towards the hotend. In the meantime, check if there is any temperature change on the LCD screen.</p>
<ul>
<li>If there is a positive temperature change it means that the hotend thermistor is working and detecting the temperature change. Most likely, the issue stems from the hotend heater. </li>
<li>If there is no change at all, most likely the hotend thermistor is causing the issue, or at least contributing to it.  </li>
</ul>


Hotend preheat error #23202 (MK3.5)

<h3>What happened?</h3>
<p>The Original Prusa MK4/MK3.9/MK3.5 is showing the message: "<strong>Emergency stop invoked by G-code (M112)</strong>".</p>
<p>Error name: Emergency stop</p>
<p>Error code: #26510 (MK4S) #13510 (MK4) #21510 (MK3.9) #23510 (MK3.5)</p>
<p>This error message can be triggered during serial printing (e.g. Octoprint) and blocks the printer control. </p>
<h3>How to fix it?</h3>
<p>Temporarily disconnect from your printer any external device, reboot the printer, and try printing using a FAT32 formatted USB drive. See if a different error would occur while printing via USB drive, and check the article relative to the new error. </p>
<div class="tip-callout">Are you still having issues? Contact our <a href="http://help.prusa3d.com/article/customer-support_2287">support team</a> and let them know that you have tried to fix the issue with these instructions. We will take it from there.</div>


Emergency stop #26510 (MK4S) #13510 (MK4) #21510 (MK3.9) #23510 (MK3.5)


<ul>
<li>Binary G-code settings</li>



<li>Wipe tower weight</li>



<li>Bug fixes</li>
</ul>


2.7.1


<p>Initial release for Original Prusa MK3.5</p>


5.2.0

1.00


<ul>
<li>MMU3 support for the MK3.5</li>
</ul>


5.2.1


<ul>
<li>Bed Level Correction</li>



<li>Support for Revo hotend</li>



<li>Mesh bed leveling fix (7x7)</li>
</ul>


5.2.2


<ul>
<li>Improvements to multi-material printing</li>



<li>Vase mode smoothing</li>



<li>Support for 3MF files generated in BambuStudio</li>



<li>Metadata with boundary polygon of each object</li>
</ul>


2.7.3


<ul>
<li>Objects from 3MFs generated by BambuStudio now retain multimaterial painting when loaded</li>



<li>Fixed a bug where downloading files from Printables did not work when enabled in Preferences</li>
</ul>


2.7.4


<ul>
<li>Touch support</li>



<li>Stealth mode</li>



<li>MMU3 support</li>



<li>MMU3 firmware auto-update</li>



<li>Time Zone settings updated</li>



<li>Bed Level Correction (MK3.5, MINI)</li>



<li>Improvements by the Prusa community</li>



<li>Bug fixes</li>



<li>Known issues</li>
</ul>


6.0.0


<ul>
<li>Japanese language support (MK4, MK3.9, MK3.5, XL)</li>



<li>Stealth mode corrected (MK4, MK3.9, MK3.5, XL)</li>
</ul>


6.0.1


<ul>
<li>Improvements by Prusa community</li>
</ul>


6.0.2


<ul>
<li>Interim solution of USB disconnect issues (MK4, MK3.9, MK3.5, XL)</li>



<li>PINDA off-bed probing repaired (MK3.5)</li>
</ul>


6.0.3


<ul>
<li>Prusa Connect integration</li>



<li>Prusa Account integration</li>



<li>Improved UI</li>



<li>Improved G-code Viewer</li>



<li>New system profile updating system</li>



<li>Single Perimeter for top and bottom layers</li>



<li>Extended SLA layer separation configuration</li>



<li>Bug fixes</li>
</ul>


2.8.0

6.0.4


<ul>
<li>Support for MK3.9S and MK3.5S printers</li>



<li>Numeric keyboard</li>



<li>Custom names for steel sheet</li>



<li>User-configurable hostname</li>



<li>Binary G-code check</li>



<li>ESP firmware flash during boot (MINI, MK3.5/S, MK3.9/S, MK4/S)</li>



<li>New bootloader 2.3.5</li>



<li>Network Status screen</li>



<li>Steel sheet name in footer (MK3.5/S)</li>



<li>Powered Z-motors during calibration procedure (MK3.5/S, MK3.9/S, MK4/S)</li>



<li>Default nozzle diameter set to 0.4 (XL)</li>



<li>Bug fixes</li>
</ul>


6.1.2


<ul>
<li>Issues with numeric keyboard repaired (MK4/S, MK3.9/S, MK3.5/S, XL)</li>



<li>Returned nozzle diameter setup (XL)</li>



<li>Printhead position during calibrations changed (MK4/S, MK3.9/S, MK3.5/S)</li>



<li>Cold pull (XL)</li>
</ul>


6.1.3


<ul>
<li>Improved menu bar, the menu no longer hides under a button</li>



<li>Two new parameters (Abrasive material and High flow nozzle) for G-Code checks</li>



<li>Improved automatic orientation of bridges</li>



<li>Number of bugfixes</li>
</ul>


2.8.1


<ul>
<li>Multiple beds and bulk export</li>



<li>Scarf seams</li>



<li>Printables integration</li>



<li>Paint-on fuzzy skin</li>



<li>Improvements in painting tools and multi-material slicing</li>



<li>Basic support for printing with different nozzle diameters</li>
</ul>


Original Prusa MK3.5

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