[Amps] SB-220 Flash/Bang

[Tim Kass]

Excellent Ideas Rick, I should wait to see what Carl weighs in on, but I will add... remove the tubes before testing...might as well test them as well, but might be a plate short to ground.. caps go bad easily too.  My Hunter 2000C was a new kit and it failed right after building it... turned out to be a bad electrolytic...they were new... so dont assume anything...but at least you got one of the more easy amps to work on. Let us know what you find out..
 
73, Tim K8WBL

--- On Mon, 7/30/12, Rick Stealey <rstealey at hotmail.com> wrote:


From: Rick Stealey <rstealey at hotmail.com>
Subject: Re: [Amps] SB-220 Flash/Bang
To: kennedyjp at cableone.net, "amps at contesting.com" <amps at contesting.com>
Date: Monday, July 30, 2012, 8:53 AM



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

                          
_______________________________________________
Amps mailing list
Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps