Solar King SLK-4000 4KW Grid Tie Inverter Repair

[Photon939]

I've been looking at doing a solar installation for my house and came across this inverter for $100 on ebay. It claimed the inverter had "RELAY FAULT" on the LCD which was shown in photos. I think to myself cool, this could be an easy fix.

Check out the bodge capacitors on the gate driver IC

[Photon939]

I found it interesting that the main transformer is potted in a block of silicone way off to the side.

So I get to work taking out all the screws and popping all the power devices loose. Hello, what do we have here? Seems one of the devices got the ass blown out of it. Fairchild HGT40N60A4 600v IGBT, neat. Looks like I can still buy one from mouser for $13. I hope the gate driver IC hasn't died with it. Maybe I should order one of those just in case.

The traces between collector and emitter are gone. Main fuse still A-OK though. Makes sense though, there's a crapload of capacitance on the main rail. Probably made a good bang when it went.

[WastelandTek]

I hate stuff like this, seems like every time I stuff new parts in an inverter they instasplode on powerup.

[DaJMasta]

Some good old high energy damage going on, but is that a shriveled cap in the first post or did the back of it blow out like a balloon.... haven't seen that one before 

[Photon939]

Some good old high energy damage going on, but is that a shriveled cap in the first post or did the back of it blow out like a balloon.... haven't seen that one before 

It's just two caps glued together with some of that brown snot glue.

I just found another failed IGBT, it seems the one that a chunk blew out of is not the same as the one that blew the traces off. Seems one failed open the other failed short. Short to all three terminals. I will almost definitely need to replace the gate driver IC. Mouser's stock of those is currently backordered until Nov 3. Bleh. Maybe I can use that time to see if I can get an equivalent IGBT that is a bit cheaper.

[Photon939]

Sorry for double-posting but considering the IGBTs used in this inverter are $13/each would it be possible to substitute? Mouser has other IGBTs that have the same current and voltage ratings for much cheaper although their max power dissipation is lower. Original IGBT is a Fairchild HGT40N60A4.

I haven't had to substitute an IGBT before. Seems they don't list anything like gate capacitance or anything so are there any critical values to watch for?
Thanks

This one seems to be the best substitute I've found so far:
https://www.mouser.com/ProductDetail/IXYS/IXXH80N65B4/?qs=sGAEpiMZZMv4z0HnGdrLjtBI7mva2f6RCLszTNq3UfA%3d