MGE UPS - Pulsar M 3000RT Repair assistance

[stephenvr]

Good day all! Newbie here and my first post. I have 6 of the above mentioned ups that need repairing. No circuit diagram, so firstly, I'm asking if anyone has schematics. Error on most of them is 707 - min invert voltage ..
I picked on a post that one should check capacitor C14 for low capacitance. This was the case in all with them measuring 10% of the value. I also noted that capacitor C9 had also lost most of its value. These capacitors form part of the input filtering by the looks of it. Once these were changed, the units came back with same error, or error 007 (fan) or other errors.
Can anyone assist me with further with a schematic or guidance?

[kripton2035]

there are not a lot of inverter schematics out there, and less even for commercial ones...
did you check the batteries ? most of the times this is the only problem, and they all fail with bad batteries one day or another.

[stephenvr]

Hi kripton2035, new batteries.

I know C14 plays a role in this fault as once changes, you get different errors. Sometimes if you leave the unit on and just keep trying to restart, it might actually start and then run with no problems at all. Thanks for responding though.