stvaly

This evening I finished replacing the 4 IGBTs and put everything back. I was nervous getting ready to start the inverter and was ready for any outcome, including a bang 😁 To my delight, it started with no error and it works like new! Finally back! I'm so happy for this success. I'm grateful to the community for help, especially @Coulomb Many thanks!

You got that spot on, I measured the IGBTs and all 4 are shorted between SD. 3 of them measure ~ 50-60 ohm between GD. The good thing none of the IGBTs exploded and the damage seems minimal. I like to think it's because I have residual current protection installed before and after my inverter. But maybe it was just luck. I also measured the resistors and diodes that feed the G pins and the driver circuits, everything seems ok. I will come back with updates as I progress with the repair. Great help! Thanks!

Hi Coulomb, Thanks a million for the schematic, will continue testing the board when I have more time. I'm getting zero ohm across the 3 components inside the pink marked area, not the inductor or transformer (I know that would measure zero with a multimeter). I think the yellow component is a capacitor, the blue a varistor for overvoltage protection, and not sure what the green one is, maybe also overvoltage protection. It just seemed odd to me to get zero across those. It might even come from somewhere else, I just did a few quick measurements and discovered that. Do you think it's possible to get 0 ohm on these components on a working board?

Hi @maxo, Great insights on error 51 and 09 and happy you managed to revive your unit. I have an Axpert 3kVA, 24V, 80A MPPT, "branded" MPP Solar, bought in 2016. I got the same issue, error 51, reset 2 times and then inverter did not work anymore with error 09. It is only charging the batteries with the power switch in off position. I opened the unit and inspected all boards including the main board, where I think the problem is, and found no visible damage, no blown components, not even heat marks. Maybe I am lucky and the damage is not that bad. I did find some zero ohm reading in places I think it shouldn't normally be (see the pictures) If you can post the circuit diagram of your board, even if it is not finalized (and not the same model) that would still be of great help. Any ideas where to look? Thanks a lot to anyone that can help. Valentin