Joe's Pye R33.

[Joe]

Pye were too mean to fit dial lights so I did. Darned nice they look too.

C6, R2 and R6 are OK but I'll check the others.

At least it's an excuse to get the heavy artillery out as you say, Alan.

Thanks

Joe

[AlanBeckett]

Joe,
It's called 'Value Engineering'
These Radios probably got stuck in a corner somewhere, tuned in and left there for the duration.
So what do you want Dial Lights for?
Where did you power them from?
Alan

[Joe]

As far as I can tell C7 is OK.

This is the trace across C21 with the 'scope set to 50mV and 10mS/Div

   

I've had on flash which gave me enough of a shock, emotional rather than electrical, to make me realise that I'm well out of my depth and having the equipment and the knowledge to use it are very different things.

As for signal injecting, all is well as far as pin 8 (a"d) on V2 but there's nothing if I try on pins 6 (a), 1 (g2) or 2 (g).

I'm calling it a night now and will study the circuit and hope for inspiring dreams.

By the way, here's the circuit for the "Bodged in" dial lights:-

   

- Joe

[Mark R]

Sounds like the valve/base then on V1/V2

cheers Mark

[Joe]

Thanks, Mark, I'll check it out tomorrow as my back has had enough of bending over it for today.

Alan: to me a 'Vintage' radio without dial lights is like a spaniel without ears. I was also prompted by wondering why it was apparently dead but was switched off on the socket. At least if something lights up you know it's getting power. I suppose Freddie Mercury hit it: "I'd sit alone and watch your light, my only friend through teen-age nights."

I'm sure it wasn't fitting them that's directly done any harm; I must have disturbed something while doing so and if there is a dry joint of iffy valve base it's as well it was flushed out.

Thanks again for the tips.

- Joe

[AlanBeckett]

Joe,
I wish I'd been standing behind you with a paper bag when you switched on
I'm using the Pye sheet so I don't know which is C21 on the Trader sheet. However, your results look OK assuming that you're injecting Audio. Try injecting modulated 470 kHz into V2 G1 - Pin2. That should produce Audio output which you can vary with the Volume Control. You can trace it with the scope.
I don't like your LED circuit, but that's another story.
Alan

[Joe]

I don't like your LED circuit, but that's another story.

Capacitive droppers aren't my thing either. At least it can only blow the LEDs. The circuit's actually out of the 'Newnes Radio & Electronic Engineers' Pocket Book.'

For once the component numbers are the same and I'll try as you suggest tomorrow.

- Joe

[AlanBeckett]

Joe,
Assuming that C21 is the same number on both sheets it's the Screen decoupler for the first two valves.
Why would you want to have a look at that?
Put your Probe on V3 Pentode Anode - Pin 6 - and inject Audio into the top of the Volume Control. Switch the Scope input to AC.
If that's OK inject 470kHz Modulated am into V2 Grid 1.
If it's not then trace where it got lost using the Scope.
Good luck.
Alan

[Joe]

C21 was Mark's suggestion and after the trouble both you and David have had with the electroylitics it seemed worth ruling out.

I'm not going to be able to do much until this evening but thanks for the tips.

- Joe

[Joe]

I've done as Alan suggested and here's the result:-

   

The time base was on 5ms/div, channel 1 (top) 10V/div showing the signal straight from the sig gen and channel 2 was on 1V/div connected to pin 6 of V3. I could only see a single line at the bottom so what the camera's up to I don't know.

There was a clear sound coming out of the speaker while this was going on.

Injecting RF into pin 2 of V2 produced a noise but not a very loud one.

I'm not doing any more until I've made some space as the current conditions are downright dangerous to be playing about with high voltages in.

   

- Joe