[Boatanchors] AVR-20 output transformer wiring?

[WA5CAB--- via Boatanchors]

I have a manual that includes the AVR-20A.  I don't know what the 
differences are between an AVR-20 and an AVR-20A.  One thing that I noticed from the 
schematic is that the AVR-20A may be wired for 6VDC or 12VDC.  The photos in 
the manual won't answer your question.  Disconnect one end of the 220K and 
check resistance between power plug pin 2 and 6B8 plate (that's either pin 3 
or pin 6).  If you get an open reading, the transformer primary may be your 
problem.  However, if that's the case, reconnect the 220K and jumper out 
the 1 MEG and it should work much better.  You'll need a HI-Z headset (HS-23) 
or loudspeaker (LS-3 or LS-7).  Oh, and a 0.1 ufd from plate to headset jack 
(which is shown dotted on the schematic).

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

In a message dated 05/17/2015 22:40:55 PM Central Daylight Time, 
ianmwilson73 at gmail.com writes: 
> I picked up an AVR-20 (OK, this is an anchor for a tiny boat).
> Electrically this is in good shape except that someone has
> performed magic rites on the output circuit. There is some
> audio output but it is very low and has a pretty high LF
> cutoff.
> 
> The phone sockets show reasonable DC resistances to ground.
> 
> The plate/screen grid circuit of the 6B8 has been hacked; there
> is a 220k resistor from the plate to B+ and a 1M resistor from
> the screen to B+.
> 
> I cannot identify the connections to the primary of the output
> transformer underneath the chassis. Just too many wires. And
> the regulator subchassis blocks some of the view.
> 
> If the transformer is o/c, I may have a replacement. But I
> don't want to start on large disassembly jobs until I can take
> some measurements.
> 
> Does anyone have a picture/description of where the
> primary leads run?
> 
> Thanks for any info,
> 
> 73, ian K3IMW
>