[Amps] SB-220 Flash/Bang

[Rick Stealey]

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