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Re: [Amps] SB-220 Flash/Bang

To: <kennedyjp@cableone.net>, "amps@contesting.com" <amps@contesting.com>
Subject: Re: [Amps] SB-220 Flash/Bang
From: Rick Stealey <rstealey@hotmail.com>
Date: Mon, 30 Jul 2012 12:53:21 +0000
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Hi Jim,
I'm surprised you haven't gotten a bunch of replies already.
Sounds to me like a short on the RF deck side of the B+, after the B+ passes 
through your glitch R.
Although I don't quite see why the step start R is failing, unless the relay 
that shorts it out
can't get voltage.
Possibilities are: bad B+ bypass, bad tube, shorted coupling cap.
Start by not installing the glitch R and see if the PS by itself will come on 
and be stable.
Remember you won't have B+ metering available on the front panel.
Next, check to be sure the rf choke across the load cap is still good.  This is 
vital in case the
coupling cap was bad and the B+ took it out.
If B+ is ok, re-install the glitch (you could install a higher R for testing), 
lift off the plate caps from 
the 3-500s and see if the bypass and coupling caps are ok with B+ on them.
If you get this far, try one tube at a time to try to determine which one is 
failing.
Since you obviously know your way around amps I won't repeat the usual safety 
precautions and 
insult you.

Rick  K2XT

                                          
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