Call the people at solaronsale.com
They repaired my Trace inverter back in 1999, and it has been working great since that time. Sure the repair was $450 on a inverter that when new was only $750. I had plugged into a 120 volt circuit with the neutral and 120 volt wires reversed. . . My M1512 inverter has a neutral to ground relay that is not found in most other inverters.
I have a true charger 20 amp, and yes it is nice. Did you know that even if left plugged in for 30 days, it will go into a bulk mode on it's own? It is one of the features talked about on a Home Magazine article written before I bought mine, (back in the 90's).
It seems like it would be worth it to try replacing the capacitors and see what happens. I was listening to a radio repairman at my work, and I bought him a portable radio charger with a bad fuse on it, that was blown. They first checked the rectifiers, and found a shorted rectifier in this charger.
Good luck,
Fred.