Thanks for the earlier advice on contacting the mfg - Xantrex
and talking to their Tech Support.
They had me do one last test, disconnect the shunt sence wires for the problem batt bank that enter the Link 20 unit. Put a jumper wire fron one lead to the other, they said the meter should read 0. If it does not (and it didn't) it means the unit is out of calibration and cannot be repaired.
But apparently, anyone that owns one of there products and uses there support, they put you on the 'Loyal Customer Program' so instead of buying
a new unit at Westmarine for $350.00 they will send me one for $150.00. I'm happy about that.