[Amps] TL922-one tube dead?

[Fern Rivard]

Andy:
    Are the filaments on the 2 tubes in series or parallel?  If they are 
in parallel, you likely have just lost the filament on the one tube and 
the filament transformer is likely all ok.   Fern

----- Original Message ----- 
From: "Andy Diethard Hansen" <HB9CVQ at hispeed.ch>
To: <amps at contesting.com>
Sent: Saturday, December 09, 2006 4:35 PM
Subject: [Amps] TL922-one tube dead?


>
> Hi Group,
>
> My modified TL-922 (230V/50Hz) created some humming noise in the past 
> month
> (may be filament transformer-somehow remaining after PA switched off) 
> before
> going to half power after 15 years, yesterday. Some smell came from 
> the amp.
> The noise now is very strong  when switched on and will reduce a 
> little
> after a while.
> Looked from the outside first like some arcing on the board right next 
> to
> the left upper corner. One tube is now not heating anymore (left from
> front). Grid Idle/plate current and power out are down to 50% normal 
> in CW
> and SSB. HV is normal. I assume one tube has gone to heaven (matched
> pair?-3-500Z orig.)
>
> Questions:
>
> Where do I get quickly a reasonably priced (set?) of tubes and a
> FILAMENT Transformer???
>
> Any other advice/comments/experience? tnx for help
>
> Andy HB9CVQ
> www.qrz.com/hb9cvq
>
>
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