XMT350 exploded capacitors

[johhnyman]

Does anyone know how to test the IGBTs on an xmt350? My capacitors exploded yesterday. Heard that it takes the IGBTs with them or the IGBT caused it and the PC-2 needs to be checked out and some resistors replaced at least if not an entirely new PC-2 interconnect board.

I am going through the pre-power checklist from the ready-arc xtreme 360 manual... actually the machine is a 360 but same thing as a xmt350 afaik.

The part I am confused about is checking the IGBTs (Mod 1 and Mod 2 designation in the manual). I dont understand how to do it really and also I would like to visually inspect the IGBTs for damage, but not sure what happens when I remove the PC-2 board? Do the IGBTs stay behind on the heatsink and I can just put the board back on or what?

Any help would be appreciated

[1997CST]

Try doing diode tests across each. If there is a dead short across any of them both need to be replaced. If one tests different from the other thats a sign one is bad also. Check the diodes and resistors on the power board.

[blue_tech]

The best way to test the IGBT modules is by the pre-power tests in the manual. There is not an effective way to test them by just looking at them or inspecting them from the outside, so no real advantage to removing the PC2 board. Stick with the pre-power checks and make a decision of repairs on that.

[jjohn76]

A lot of times you can get away with replacing just the capacitors and bleeder resistors if the pre-power checks are all ok. Ensure you also check the resistance across the bleeder resistors/capacitors. The older tech manual doesn't have that check. The older bleeder resistors (black wirewound ones) often failed, and when they did, one of the capacitors would overcharge and blow. The machine control circuits usually caught this issue and shut down before melt down.