Err: PRINT FAN ERROR

what does "drastic" or "large" fluctuations in the rpm mean? i get variations by 500to 7-800 rpm. is that normal?
edit: I was checking extruder info during a test print and it dos go sometimes to 0 (and the fan stops somentimes, but mostly stays on) and eventually gave the error. does this indicate a small fracture in the yellow cable? or maybe one of the other fan cables, I fear..

I had super tiny micro nicks on the cable and I'm so tired of buying replacement parts that I just decided to find the point, chop that bit of cable off and crimp some dupont connectors and call it a day. Works fine and saved me a few days of no printer, plus some money on the parts/shipping.
Plus, I had bought this new fan not long ago, directly from Prusa. Lasted like around a month. Not great. 
Could've tried to get some warranty on things, but I guess a nick on the cable is considered wear and tear and I fixed it in less than an hour, not days of emails and shipping delays.
Quite annoying to see things this flimsy. I would really like to see a more sensible approach to these things, like having a more appropriate flex cable bridging off to a interim PCB on the extruder assembly where the thermistor, motor, PINDA and both fans are plugged in.
The hotend cable would still need to be routed directly as it needs a thicker conductor, but the rest given their signals and voltages are so low, there would be no reason why not to.
I know this would make the extruder assembly a bit heavier, but that would eliminate the need to buy Prusa-specific hardware due to long cable lengths or other stuff. And if the connector at the main board is one for all (not a break-out cable) then the board itself could be a bit less cluttered as it wouldn't need a 'port' for each element. I believe the gains would outweight the pains. The flex cable choice would naturally be optimised for such a purpose, probably also leading to a lighter 'tail'.
Idk, just an idea and sharing my experience. -- I'd encourage others to do something similar, as when this fan dies, I won't need to cut all the extruder cable ties, undo the sheath, open the board enclosure and all that, potentially stuffing up something else; I'd just disconnect, connect the new one and that's it.
100% my new approach as I hate having to wait weeks at a time whenever I order any parts. I'm in Australia and the few vendors that have Prusa-specific parts often they don't carry enough stock so I end up ordering straight from Prusa, and the shipment from CZ to AU is naturally not the quickest (nor the cheapest), leaving me for days at a time without a printer. (I learned my lesson, and I try to always have at least a few replacements at hand)
I might try to come up with a mod for this.

Hello, I don't have print fan errors but the fan on my mk3s (upgraded from mk2-something) is acting weird.
First, running at speed 255 I am getting relatively low but consistent readouts of about 2800 even if the fan is spinning full speed. The funny thing is that if I brake the fan manually the rpm jumps higher. If I set the speed to 128 the speed also jumps to about 4000, all consistently. This looks kind like a numeric overflow but I don't have any other printer to check.
Second, if the fan is not running at the full speed, the rpm oscillate. Once per several seconds it drops, then returns back, both audibly and in the numeric value. It is not affected by the X axis movements nor by trying to manually press on the cable or wires and is IMO too regular  in both frequency and the amplitude to suggest a mechanical problem or a damaged wiring. I don't think the fan rpm is regulated by a closed loop, the firmware just sets a pwm duty cycle, right?
I have cleaned the blades and put a few drops of oil under the sticker, that did not change anything at all. The firmware is the most recent 3.12 one instaleld a few days ago.
The prints are fine. Can this be normal for the upgrades and/or printers that did accumulate some hours working or do I have a problem, maybe in the electronics or even the PSU?
Thanks

I started running into the printer fan error just a few hours ago. Initially, prints would stop because of the error but the fan would still be working. However, after checking for possible obstructions or dust (there was none), and then trying to move the printhead along the x-axis manually to check for issues, the fan seemed to stop running entirely, and now will run briefly upon startup and them abruptly stop and give me the error. This is confusing as it doesn't quite match up with the usual problem I've been reading about online (where the fan either won't run at all, or where it runs fine but gives an error).I checked all the visible wire connections in the back, but saw no visible signs of breaks, and carefully moving the wires around didn't lead to any apparent changes to the fan (it didn't go back on intermittently or anything). I then tried disconnecting and reconnecting the fan in the EinsyRAMBO, and while this still didn't fix the problem, I did notice a black wire with a tag labelled with some numbers and "fan", which also seems to connect back to the printhead unit along with the red wire, and *this* does appear to be visibly bent in the middle, possibly suggesting a break?  The problem is I can't find a specific reference to what this wire is online, nor how I might go about fixing/replacing it (assuming that is indeed the problem here), so I'm at a loss for what exactly to do next. It seems like most people have trouble with the thinner red, black, and yellow wires the connect directly into the back of the printhead.

Print Fan Error at random points, and when navigating back to main menu.
 
I experienced the annoying Print Fan Error repeatedly. In my troubleshooting I could not recreate the error by moving the axis with the fans at 255. However, when I navigated BACK to the main menu, as soon as I would click the final step back to the main menu, I could create a Print Fan Error 100% of the time.
 
Other than that, the print fan is throwing an error during prints at random points along the x axis, with none of them at any strain points on the wiring harness. Any ideas? I am okay with simply replacing the fan if that will work. I just want to get back to learning. I have only had this since Jan/Feb, and I ordered it pre-assembled, so it's not like my machine has a lot of miles on it. Appreciate your feedback.