[Elecraft] KPA500 refused to turn on using the front panel ON button

[Lawrence Allison]

I have the same problem.  KPA500 (sn0856) on/off normal for 9 months,
started to act up after KAT500 tuner installed.  Not a real problem, just
reach behind and cycle power switch and it operates normal for a while.  I
would be interested in seeing the cure.  Interconnect cables are home built
and checked several times.
73
Larry / WA9EBX