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Hot end not heating up, used to work  

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martin.s48
(@martin-s48)
New Member
Hot end not heating up, used to work

Hello everyone,

I am resorting to a post on the forums since after 1 week of troubleshooting I am left with no solution and feeling very frustrated. Here is some context:

I bought the Prusa i3 MK2S Kit and assembled it over a weekend, after the initial calibrations and much playing around with PINDA probe height I finally passed all of the calibrations (selftest, Z axis, xyz axis, and live z adjust using the v2calibration). I successfully printed the Prusa logo and everything worked and looked great! However, while printing the Benchy boat I received a thermal runaway error after an hour and had to abort the print. Turns out when I wired the left hotend fan (the smaller one) I somehow got some wires inside loose and the fan gave out halfway through the print (that fan fails the selftest afterwards). I'm guessing the temperature change must have caused the thermal runaway error. No worries, ordered a new fan, rewired it, successfully passed the fan selftest, but as I was about ready to celebrate the selftest states that I have a hotend error! Hotend/thermistor not wired properly. The hot end will not heat up past room temperature, it sometimes hovers 1 degree celsius above room temperature but quickly goes back down.

What I've checked: voltage on the power supply correctly displaying 12V, board has red LED's on, wiring is not faulty or damaged since it was tested with the multimeter "beep function" which indicates voltage is running through. I also checked that the thermistor is registering properly by putting a flame nearby (and it quickly shows an increase in temperature). The heated bed works properly as well, when setting the printer to preheat to PLA heated bed goes to 55C quickly while hotend stays at 22C. There is still PLA stuck all the way from the feed to the nozzle so I'm not sure if that makes a difference. Running the proper firmware: FIRMWARE 3.0.12 (JULY 12, 2017).

I am by no means an electrician but I think I have checked everything... I removed the big fan and the orange plastic to take a look at the hotend and to check for damage but can't see anything. Do I need a new hotend?? What is annoying is that the printer was working great on the first test print but now it's been out of commission for 2 weeks and I was really looking forward to learning/printing.

Can someone point me in the right direction, I would greatly appreciate it!

Posted : 19/10/2017 1:10 am
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