[Elecraft] KRC2 Failure

[Jim Brown]

For about two years, I've had a pair of KRC2s in my SO2R station, each 
driving a WX0B switching matrix for W3NQN filters.  They have worked 
fine.  Friday, our power was off so that PG&E could do some maintenance, 
so I pulled power from a bank of power pole outlets that feeds one of 
the KRC2s to minimize discharge of my backup batteries.  After restoring 
power, the KRC2 has failed, in the condition that the WX0B matrix (only 
relays) does not pass signal.  If I remove power from the KRC2 the WX0B 
box does pass signal.

Any ideas as to what would cause this failure?

73, Jim K9YC