Pax/Mike.. Good trouble shooting as Ron mentioned. Question: how did you conclude that the rj11/and adapter, was bad? Was it burned and looked bad, or did you do a ohmmeter test? If it was a burned appearance, than Ron you may have a point with too much current.
My Xantrex died this last season in Arizona, so upgraded to the new 2000 pure sine wave model. Not that happy with the first unit, as it tripped GFI's when on shore power, and was very high RFI noise. Being in ham radio, this wasn't a good thing. They sent me another unit, but just installed it and don't know about the GFI problem as of yet. RFI noise was about the same, but adding some toroide chokes on the 12 volt cables and a 22000MFD capacitor across the 12 volt cables, killed most of the noise. At least made it manageable, radiowise.
BTW... the new 2000 uses the same footprint remote unit, but uses a next size larger RJ45 cable. So I had to pull the old cable out and replace it with the new larger 8 conductor cable. Kind of a pain...
Denny and Barb