[Amps] AL-80b Problems - Help Needed

[Carl]

Check all bandswitch contacts

Carl
KM1H


----- Original Message ----- 
From: "Bob Moore" <ki6iv at sbcglobal.net>
To: <amps at contesting.com>
Sent: Thursday, March 15, 2012 2:41 PM
Subject: [Amps] AL-80b Problems - Help Needed


>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
>
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