Hi Steve,

Merry Christmas.

Yes, on reason for ERR12V is the connector to the PA board.  I believe another cause is a power supply issue.  It's easy the check the voltage at the radio.

I had this issue with my older K3 (SN1428) and replaced the connector with ones using gold pins. They changed to gold pins at some time (SN in the 3000s?) When I had my issue, I couldn't raise the power output above 12 watts.

There's a lot of history on the Elecraft reflector and in the groups.io list.

73,

Gerry, W1GD