Moved printer, attempting print damaged board, blew another

Arkadiusz

If it occurred twice with 2 boards that would indicate there is some fault with your hardware. Problem happens when you are trying to print, so lets narrow it down to heaters.

bass4aj

@arkadiusz good idea. do you know what I should look for with a multimeter? I agree its likely hardware but I am not sure how/what to look at.

Veti

check the resistance of the heater.
then check the resistance of between the heater and the thermistor.

do this with the bed and hotend.

there should be a little bit of resistance for the heater and no resistance between heater and thermistor.
do wiggle the wires while testing.

bass4aj

@veti resistance between heater and thermistor? The heater is a pcb bed and the thermistor is a cartridge style pt1000 attached by Kapton tape. Or are they linked through the board somehow?

Veti

they should not, but the there could be a short on the hotend. when you power the hotend that would send vin to the thermistor connector.

bass4aj

@veti Ah gotcha. I will get those checked and post back. Thanks

dc42

What PSU are you using, and have you checked that it is outputting the correct voltage? Over-voltage at the input could cause U3 to fail.

bass4aj

@veti there is no resistance between either heater/thermistor. Both heaters have some resistance. Looks normal. @dc42 Its some generic supply that M3D put on the Promega printer. Its a 24V supply. DWC reads a constant 23.7V or so, and a check with the multimeter (after detaching from the board) shows 24.1V.

bass4aj

@dc42 I also just confirmed, its not U3 that blew. L2 blew. I was touching it with a pick and the whole part just fell off lol

bass4aj

@dc42, what kind of things could cause L2 to fail? I should also mention I saw a different thread in the forum with a similar bed issue (but not quite the same). In that post, you suggested to disconnect the bed ground and tape it to the frame. On the first board when I did that, the bed heat light stayed on, but the bed stopped heating up on start-up if that helps.

dc42

L2 masy blow if either U3, C6 or C12 fails. Unless C6 or C12 looks damaged, my guess is U3.