MK3.5S Preflight Check: Hotend and Heatbed won't heat up [Power Panic Issue]
I upgraded my Prusa Mk3s+ and made it all the way through all of the setup tests until I got to the hotend and heatbed testing. Neither would heat up at all. The thermistors both worked properly and after checking with a multimeter, saw that the terminals from the power supply both read correct voltages, but no power was being supplied to the heating elements.
During dissasembly of my Mk3s+, the power panic connector was very firmly set into the female connector to the power supply and it pulled the plastic female housing off of the pcb. When I tried to reinstall the female connector onto the pins, I broke the power panic pins off of the circuit board. This broke continuity with one of the connections necessary for power panic functionality.
[DISCLAMER, do not repeat what I will describe. Open power supplies are extremely dangerous to handle.] I shut down the printer, opened the power supply housing, and removed the circuit board. Upon inspecting the power panic pin holes, I noted that they were only soldered to surface traces, and those traces had broken free (see below). I unsoldered the pins, resoldered all of the broken connections, resolded the pins, and reinstalled the female power panic connector with glue. This fixed the issue with the heating elements and now my printer functions as expected.
Having the pins of a connector soldered to surface traces instead of a plated through hole (PTH) seems like a design flaw to me as it makes the connector far more delicate and in this case completely disabled the printer when broken. If I had not taken the risk to repair the power supply myself I would have likely needed a replacement as I saw other users had to in a reddit thread I found: https://www.reddit.com/r/prusa3d/comments/1bgzeb4/update_mk35_bed_and_nozzle_wont_heat/
