I’ve nearly finished restoring my Westinghouse clone of the AWA 227, the W2111.

I've done the usual waxie eviction, to no avail. The fault is:

The sound is usually very quiet when the set is running. I go to turn up the volume, and only when it is all the way up do I get comfortable sound. When the sound source is large, e.g a crescendo during a music performance, or when there are bursts of loud noise, the sound cuts to full volume, nearly blowing one out of his seat, and then immediately going back to the quieter volume.

I've also WD-40'd the volume pot.

Thoughts? Bad valve?

Oli

From memory and not looking at the circuit, I would locate the audio ratio detector transformer and give the tuning slug a slight rock back and forth.
Also, WD40 is not a good idea on volume controls.
There are better products, even Kero.
JJ

Hello JJ,

I will try that and see/hear for a difference. Thanks!

Maybe I need to invest in some proper contact cleaner...

Oli

No success!

How did you go with your audio injection cable?

Have you determined if it's before or after the volume control?

Not yet unfortunately. Soon, no doubt!

Oli

I have now..!

When audio is injected after the 6AL5, just before the volume pot, still there.
G1 of the 6AV6, Still there.
G1 of the 6AQ5, Still there.
Plate of the 6AQ5, Still there.
I've also checked the speaker and its transformer.

Maybe it's the 6AV6's plate load resistor?
Thoughts?

Oli

Injecting a signal into the circuit uses just that part of the circuit that comes AFTER the point where you injected it.

So, if the fault is confirmed to be still there when you inject a signal at the 6AQ5 plate, the fault must be after that point.

Which leaves 3 possibilities:

1. A fault in the speaker transformer
2. A fault in the speaker
3. A bad connection before or after the speaker transformer

Probably worth substituting a speaker, connected to the output wires from the transformer that currently connect to the speaker.

Measure the speaker transformer primary (ohms, power off) at the chassis socket terminals, you might have a bad connection in the plug - socket. It should read about 400 ohms.

If that checks out, all that's left is the transformer, assuming you are sure about you observations. Maybe a shorted turn in the primary winding,

All fixed.
Turned out to be the plate load resistor, R116, which is supposed to be 330Ω, had gone high to 5.5kΩ. I ended up replacing it with a 470Ω. And that was it!

Oli

**B+ Dropper resistor, not plate load!

B+ dropper you mean.

It pays to check voltages. That would have shown up immediately.