[AMPS] Alpha 78 problem

[km1h@juno.com]

On Fri, 9 Oct 98 07:18:06 -0800 Rich Measures <measures@vc.net> writes:
>
>>
>>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


Lacking a HV tester you can try with one tube at a time and go from
there. It is unlikely that both tubes will share the same failure.
Many contesters have limped along on one tube....just keep the drive
down.

73  Carl  KM1H



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