[Elecraft] ALC THR level KPA500

[Dave]

Elecraft fitted the wrong type of Op amp on the front panel of the early
serial amps. Mine is serial 573 and had the same problem. With the wrong
part, you get the constant output Voltage fault. From memory it is U8, but
cannot remember exactly.

Contact Elecraft Support for the correct IC. It is a surface mount part,
but not hard to replace. You might also ask about mod kit E850607

73 Dave G4AON