Battery -> MOSFET's -> ferrite transformer-> rectifiers -> black electrolytic HV DC caps (about 250vdc for 120vac inverter) -> PWM sinewave generation IGBT (4) H-bridge -> output PWM L-C filter. -> AC output. That is the basic functional path.

Looks like a regular run of the mill sinewave inverter. The five transformers are battery to HV DC boost converter. Each transformer usually has its own set of MOSFET primary side drivers. Basically, just parallel group of smaller transformers to build higher power output. Output boost up battery voltage to HV DC. It runs about 18-24 kHz. HV DC PWM chopped by IGBT's and filtered to sinewave by L-C filter.

Common for some of the battery side MOSFET's to be toast. Check drain to source of each for being shorted. There is likely rectifier diodes on secondary side of five transformers along with transformer primary side MOSFET's mounted on the heat sinks on each side. Check diodes also. Last common problem is blown IGBT's for sinewave PWM. The IGBT's may also be mounted on heat sink on the side or separate heat sink in middle of board. The IGBT's will have connections to the gooped toroid inductor.

There are a lot of other smaller support functions like power device drivers but that is particular to a given model design.

You might search some Youtube video repairs on regular inverters. You might get lucky.

source: https://diysolarforum.com/threads/inverter-repairable.38695/post-489295
https://diysolarforum.com/threads/inverter-repairable.38695/post-489358