[Boatanchors] Audio Output Tranny- Mystery Failure Mode

[Garey Barrell]

Dave -

Sorry, I messed that up.  Switch the _Polarity_  (+/-) switch back and forth to test.

Dave -

Probably a shorted turn.

Do you have a Simpson 260??

If you do, you can easily test for a shorted turn.  Switch the meter to Ohms, and adjust the range to read the resistance. Leaving the leads 
connected, turn the AC-DC switch to the 'other' position.  If there IS a shorted turn, the reading won't change much.  If there is NOT a 
shorted turn, the meter will kick HARD and rebound to the same reading.  Sometimes it helps to choose a different range, but try it on a 
good transformer if you want to see what happens.

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>

David Stinson wrote:
> Working on the Navy REP Moral(e) receiver.
> It has a single-ended class A 6V6 output.
> Audio level is about half what it should be and distorted.
> Substitution shows the problem to be both the output transformer and the internal speaker.
>
> I pulled the output tranny.  DC resistance checks show what
> one would expect for good windings.  Used a DC supply at
> 90 volts between points and had no detectable leakage between input and output windings or to ground.
>
> Ideas as to what the failure mode in this tranny might be?
>
> 73 DE Dave AB5S
> ______________________________________________________________

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