[Amps] Problem with my Henry 2K-4A

[Mark Beckwith]

Greetings,

I'm writing the [Amps] reflector in hopes that someone reading will be able 
to diagnose my problem with confidence.  It seems like the Henry 2K-4A is a 
pretty well-known amp.  I imagine the answer is here somewhere!

Lately when I transmit, after a couple minutes, I hear a very quiet "click" 
and the plate current swings positive by a little (150-300ma or so, 
depending on whether the plate voltage switch is in "CW" or "SSB"), the grid 
current goes negative, and the amp no longer transmits.  If I leave it like 
this for a little while longer, the built in circuit breaker trips.

Initially, the circuit breaker would not trip, I would hear the tiny "click" 
again and the unit would be restored to operation for a little while longer, 
before failing again.  After an hour or so of this, it stopped correcting 
itself and would only blow the breaker.

If the amp was turned off and left to cool for a while, it would go back to 
operating, but only for a few minutes until it failed again.

This happened the same regardless of the position of the bandswitch.

Now after a couple days of this, it seems to be permanently in the failed 
mode.

Does this sound familiar to anyone?

Thanks in advance,

73 - Mark, N5OT