[AMPS] Alpha 78 problem

[Rich Measures]

>
>Hi, 
>
>D44BC got a problem with his Alpha 78 amplifier, maybe some of yourguys
>can help us to guess what could cause this problem:
>
>When switching the amp ok evrything is ok. As soon as you apply drive,
>and anode current is flowing, the amp will switch off. You can switch it
>on again, some result than.
>
I would check each tube [cold] with a high-potential tester.  If the 
anode/grid leakage is over roughly 10uA @ 5000v, it is not good news.  If 
the leakage current decreases substantially with neg. polarity, the 
presence of gold melt-balls is indicated.  
-  later, Carsten

Rich. Measures.  Web site:  www.vcnet.com/measures


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