[Amps] TL-922A - Loud Pop, Blown Fuses

[Vic Rosenthal]

Clay Curtiss W7CE wrote:

>I don't
> have access to a hy-pot tester, but a simple resistance check from filament
> to grid on both tubes doesn't reveal a short.

Filament-to-grid shorts on 3-550Zs are common (I have seen two myself). 
Typically, the short disappears when the filament cools down.  A short by itself 
doesn't necessarily cause a flashover;  flashovers are often caused by gas in 
the tubes, which a hipot test will reveal.   Symptoms of a f-g short include 
very high zero signal current, and damaged components.

In your position I would try one tube at a time.  I understand your concern, 
however!

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco