Hello Solar, well on the subject of PowerJack inverters, my 8kw 24 volt inverter blew up yesterday.
I pulled it apart and yep the AC mosfets were toast, and the Optocouplers on the driver boards were seriously discoloured.
I had a couple of spare boards and a spare driver board so fitted them.
One of the mosfets blew almost straight away. They are cheap Hy4008 mosfets, so I am hoping it was just a faulty one.
While looking carefully at the inverter something I noticed was that the negative cables to the power board were all fused together at the input terminal. They had got so hot that the pvc insulation on them had fused.
I had to actually cut the cables to remove the input terminal. The screw that held the lugs on was a phillips head type and it was totally siezed in. I ended up having to drill it out and re tap the hole.
I am now thinking that a bad connection on the 24 volt side is most likely the cause of the two blowups this inverter has suffered.
So I will repair that and also put a new allen head screw on the positive side too.
I have one of those aliexpress 5kw boards running the house at the moment, so if the powerjack is completely dead I will fit an 8010 based board to the transformer and junk the powerjack boards.
Just thought that it may be worth you checking the connections on the low voltage side while you are trying to fix your inverter
Pete