C90W SeaTalk

[GBay360]

The C90W on my sailboat is on it's last leg, the power/data outlet has broke loose on the back and several softkeys do not work (power/data outlet circuit board is no longer available). But, it does still function if you get lucky and the outlet pins lines up.
I got a used replacement C90W on line. The replacement does not talk to the instruments, but everything else seems to function. Both have v2.35 and I performed a factory reset on both to make sure I was testing similar MFD's. I switch out MFD's on the boat, the old one will show SOG on the speed display instrument so the network is okay. The new one shows SOG on the MFD, but shows dashes on the speed display instrument. Is there a function in the SeaTalk system set up that needs to be turned on that may be on one but not the other? Or did I buy a unit that needs repair?

Thanks