[Amps] AL-80b Problems - Help Needed

[Bob Moore]

I need some help in figuring out what the problem is here.  Below is a
summary of what I am experiencing.  


AL-80b Problems

Normally operate in the 5-700w range, I am very conservative in the amp
operation.  New tube in Dec '05.  

Will be operating or lately tuning up and will hear an arch, loses power
out, but all voltages and ma stay normal.

Started while I was contesting running RTTY at 500w.  Started on 15m, I
could let cool and then be able to go again for a while.  Now the problem
has migrated to 20 and 40.  Still works fine on 80 and 160.

All operating voltages and currents are within the perimeters in the manual.

When it stops putting power out, I hear the arching which appears to be
coming from the right hand side of the unit.  I have noticed some arching
"spots" on the plate tuning cap.

I opened the cabinet and did a visual inspection and can see nothing out of
the ordinary other than RFC-2 (Plate Chock) appears to be discolored and an
earlier vintage than what I see in pictures others have posted. (I can send
my pictures if requested).

Any hints how I should proceed for trouble shooting.

I am going to open it up again today and clean the relay.

Bob, K6NV


Bob Moore
Truckee, CA  96161
(530)575-5766