[Amps] SB-220 PROBLEM (FINAL)

[Carl]

Perseverance works

Carl
KM1H


----- Original Message ----- 
From: <Gudguyham at aol.com>
To: <amps at contesting.com>
Sent: Tuesday, September 16, 2008 6:35 PM
Subject: [Amps] SB-220 PROBLEM (FINAL)


>
> Latest diagnostic info........Disconnected one leg of the secondary AC 
> side
> of the transformer going to center junction of the 8 caps in the 
> doubler.
> Tried it again, and the plate meter still moved and the grid meter 
> went
> negative, however it took more ac mains voltage to produce a 
> significant  movement on
> the meter.  Next I disconnected the other AC lead going to the  diodes 
> so
> that the secondary of the transformer was totally out of the 
> circuit.....now the
> meter does not move at all with full main voltage.   Looks like there 
> is
> leakage on the power transformer to ground, I took a  measurement 
> across the plate
> meter as it was moving and its only millivolts, but  enough to cause 
> the
> problem.  Suffice to say the power transformer is  leaking. Guess 
> we'll need
> another transformer.  This amp is one of the  first made so the thing 
> is pretty
> old.  Time to lay to rest.   Lou
>
>
>
>
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