Puzzleheaded

As the title says, we have an Anern 10.2kW solar grid-tie/off-grid inverter. I installed it myself, which all went fairly well, but i was having problems with neutrals. Eventually I split the neutral buses, and all was well, the system worked nicely. However, I wasn't very happy with the neutral situation, and was fiddling with connecting the DC negative to a neutral bus, through a 1amp MCB for safety. So that tripped out, and from that time the inverter wouldn't connect to the battery, but no error messages, and the remainder of the system still worked. Then came my big mistake: I was checking voltages and currents at various places, and forgot to change my multimeter probe back to the fused COM jack. Then I put the probes across the Live and Neutral incoming supply terminal. Big bang! The multimeter survived, but the inverter didn't. It still booted up, but with error message 09 "Bus soft start failed". So at this point I decided to "stop digging", and took the inverter to a place that has a good reputation with inverter repair. Long story short, after replacing 20 mosfets on the battery section of the mainboard, the inverter is still non functional. I haven't been able to find a schematic for the inverter, but it has been suggested that it is very similar to an Axpert 10.2kW Any ideas anyone?

Hello everybody, I've just read Frank's newbie post, and decided to copy his style of quite detailed intro. My name is John, I'm 69 years old and I've been living in Port Elizabeth (Gqeberha) with my wife and son since we moved back to South Africa in 2003, from Zimbabwe, where we had been living since 1980. I I have a fair grasp of low voltage electronics.