[Amps] Ameritron AL80B possible arcing?

w8hw at comcast.net w8hw at comcast.net
Thu Apr 19 07:21:54 EDT 2018

I have worked on many of these amps as well as many other amps. More than 
one issue will cause this, but the first one to think about is did you 
replace the resistors that shunt the caps that you replaced? Quite often you 
will find one of the shunt resistors are open. When this happens, it causes 
the cap that it shunts to have high voltage across it (over its voltage 
limits). Then the caps breaks down (that is the pop you hear), and the the 
cycle restarts with that voltage building up again with another pop coming 
soon. etc. You will have to lift one end of the resistors to check (ohm them 
out) them.

Hope this helps,
73, Bruce, W8HW

-----Original Message----- 
From: Jeremy Downard
Sent: Sunday, April 15, 2018 09:57
To: amps at contesting.com
Subject: [Amps] Ameritron AL80B possible arcing?

I was recently given the AL80B with a known AC issue which was found to be
the power supply caps that have been replaced with new CDE caps from
Harbach.  The amp will power up and produce power but about every minute or
so the amp will produce a loud click.  It almost sounds as if someone took
a hammer and hit the case on the amp.  Could this be some kind of HV arc
somewhere in the amp?  Has anyone ever experienced this?  Or possible ideas
of what it could be?

Jeremy KD8VSQ
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