[TenTec] Centurion- bias transistor

[Duane A Calvin]

The bias transistor blew on mine when the amp was only a few hours old. 
I replaced it (not trivial), and never had another problem until a few
years later when a 3-500Z developed the dreaded cathode/grid short.

        73,  Duane


On Mon, 12 Dec 2005 20:28:17 -0700 "Henry  Pfizenmayer"
<pfizenmayer at worldnet.att.net> writes:
> UPDATE : Yep another blwn bias transistor - second since about 
> April.
> 
> Also appears the HV is OK at about  3145 V no load as measured with 
> an 
> external Fluke  DVM , so metering is messed up again.
> 
> What I would like to know is what is others experience with bias 
> transistor 
> failures ? Bad 3-500 ???
> 
>  Hank K7HP
> 
> 
>  Centurion readings after  a POP
> >
> > Resting plate current at first division - about 70 ma.
> > Plate voltage only 2000 volts and transformer hum sounds like the 
> supply 
> > is loaded heavily but showing only the 70 ma on the plate meter.
> > No grid current
> > No fwd/reflected power
> > No difference in standby or operate
> > No difference QSK or PTT /VOX
> >
> 
> 
> 
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> 


--------------------------------------
Duane Calvin, AC5AA
Austin, Texas

http://home.austin.rr.com/ac5aa