The one that got put away time and again.

[Murphyv310]

Surprised though Sam.
This same circuit is used on some AM Pye sets too. I've one in the shed now and as I say the output winding was oc the smoothing was OK and there was nothing at all from the speaker. Zero anode volts and no not a trace of audio.

[boater sam]

Surprised though Sam.
This same circuit is used on some AM Pye sets too. I've one in the shed now and as I say the output winding was oc the smoothing was OK and there was nothing at all from the speaker. Zero anode volts and no not a trace of audio.

So was I !! Pam being Pye of course there will be similarities.
It threw me completely, it was almost usable as it was. I wasn't until I measured the EL84 anode voltage and found 3 volts that I realised that the winding was open. The hum cancelling part rectifier to HT line is intact. The odd thing was the cathode volts being so near to spec, the screen grid was making a very good anode!  I suppose around 28mA through the secondary would produce a bit of speaker drive.
Swapping the transformer restored it completely.

[Murphyv310]

Hi.
With the anode disconnected I get 3.95v on the cathode of the EL84 on the set I have here.

[boater sam]

So the grid is passing quite a bit of current, is it distressed?

Judging by the volume on mine, the valve must have good emission.

Cathode draws current through the secondary of the output transformer?

Sam.

[Murphyv310]

The EL84 is rated at 5.5ma for the G2. On mine I get 3.95v on the cathode with the anode disconnected and that's with a new EL84. There is something way out on your set Sam, the current drawn from the G2 is is way too high for you to get nearly correct cathode volts.
In fact I'll just connect the anode to G2 with the B section of the tranny disconnected to see if I get any audio.
Give me 5 minutes.

[Murphyv310]

Hi.
With the anode strapped to the G2 and not connected to the B winding the anode volts are lower obviously as the voltage is reduced by R27 a 1k in my set. Guess what......... Not a trace of audio. I think something is wrong in your set Sam, it doesn't add up. I'm not saying that you didn't get the result you have but the issue should be repeatable easily.
C46 will effectively decouple any audio on the G2.
I'll disconnect it and see if I get audio now.

[Murphyv310]

Interesting.
With C46 disconnected I now get weak audio with no distortion But with the anode strapped to G2, nothing with the G2 on its own.

[boater sam]

What do you get pulling mAs through the secondary? Or is the hum cancelling winding passing the signal to the secondary.
Can't check that now as I have connected the HT feed from the rectifier direct to the  HT line, C46, ordinary transformer without hum cancelling.

I was thinking my valve may have a screen to anode leak but I only had around 3v on the anode when I checked.  220v on the screen.
I can't see what else could give any signal, told you it was an odd one.

You can understand why I was amazed that it worked at all with the transformer O/C but it did.