[Elecraft] voltage display problem

[MARY HAYS CARNEY]

Hope to find I'm on the list.  I've completed my K2 and have some problems with the transmitter section.  However, before I attack them, I've suddenly encountered a problem with the voltage display showing 23.3 v even with 0 volts into the internal voltmeter.  The voltage into U6 at it's voltage sense input is correct, I.e. 0 v for 0 in and about 2.1 volts for 12 volts in.  Note that early on the display was correct with 11.9 volts displayed for a 12 v supply.  Any hints?
joe carney KB3FBR