Onan Genset low/no power

Grab and multi meter and check the voltage at one of the outlets inside the Rig when the generator is running. If it were me I would focus on the generator rather than the converter right now - if your generator isn't providing enough power it's going to create problems with the converter.

Here's an FAQ on Onan Generator issues - might help

https://www.flightsystems.com/pdf/onan-rv-troubleshooing-guide.pdf