Tired of buying replacement parts: Idea.
I have 2x MK3s and love them, they are really good in general. I don't print thaaaat much, but recently I had a project recently and I printed almost constantly for a week. (short batches of <10 hours each)
I was printing on white filament (yikes!) and naturally ended up with a clogged nozzle on printer #2; Ended up changing the whole heat break, nozzle, block, everything as I noticed it was leaking a bit of melted filament as well.
Of course: upon reassembly, my thermistor was dead.
Changed that, and now had issues with the fan as it suddenly died.
Ordered a new fan, put it on, all good.
Printer #1 just went down this week with a bad bed thermistor cable. Zero problems since May/2019, printing sporadically.
Yesterday Printer #2 suddenly scared me with a beep and gave me a fan error. 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 for 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' with a better cable.
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, half dismantle the extruder head, 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. The less you touch, the better.
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 if not weeks at a time without a printer. (I learned my lesson, and I try to always have at least a few replacements at hand). A more generic-compatible approach could definitely increase uptime.
I might try to come up with a mod for this, like a re-printed back for the extruder head holding a PCB where the main cable goes to and all the other smaller ones plug on. In the meantime, if someone from Prusa sees this could consider it as an idea for a hopefully-upcoming MK4.
Cheers!