[Boatanchors] SX-28 Update

[Brian A Clarke]

Hi Joe,

I have no specific experience of the SX-28.
I do not understand your diagnostic logic.
But I have a lot of experience with push-pull 6V6 amplifiers. Either the 6V6
you
have pulled is shorted, or the capacitor feeding its grid is leaking.
Most unlikely to be a shorted OPT.
However, playing a p-p amp with one lung removed gives unbalanced
magnetisation of the core, leading to reduced inductance and hence changes
in
the frequency characteristics of the trannie.

73 de Brian, VK2GCE.

You said::
>
> 1.  If I remove the back 6V6 (the one behind the 5Z3 and the front 6V6),
there
> is no smoke. This suggests to me that that part of the primary is shorted.
The
> interesting thing is that even with one 6V6 removed, the radio plays great
and
> has more than enough volume. Do you agree that this shows that the primary
is
> shorted?
>
> 2. I checked the cathode voltage. It is about 16V, well within the margin
of
> error of my voltmeter. Further, the resistance from cathode to ground is
200
> ohms, right on the money.
>
> 3. I'm thinking of leaving it alone and playing it with the one 6V6
removed. Any
> thoughts?