Joe's Pye R33.

[Joe]

I received an R33 yesterday.

       
       

A quick look revealed that the wave switch was very iffy and the HT was down to 115v against the specified 225v.

Following David's experience the first thing I tried was changing C28 (32µF). This altered the voltage OK - down to 109v!

I then stuck a 1N4007 in and got two-hundred and eighty-odd. After fiddling about I changed R16 to 150Ω, from 22Ω, which gives 231v (digital).

I was rather disappointed with the sound quality despite having fitted a new tone corrector cap. I tried it playing through my ex-R600 and it was much better. I agree with Alan about it being a bit shrill but upping the tone corrector to 0.047µF, from 0.01µF, would deal with that.

It now needs a general faffing about with and the speaker and wave switch need assessing as to whether replacement is called for.

As for THAT capacitor, it looks like a Mullard Mustard, though bares no maker's name. I put it on my megger and the needle didn't move and when I stuck 350v DC up it it only leaked 0.05mA.

- Joe

[AlanBeckett]

Get scrubbing on that case young Joe.
It will look quite pretty when you've done it.
Changing the Wavechange Switch would be a 'challenge'.
Alan

[Joe]

The case has been scrubbed but awaits a polish.

I don't think the wave switch would be too bad as it's only a three-pole two-way thing.

- Joe

[Joe]

I haven't really done anything to it today but have polished the case up. I've got a nasty feeling that the 'Brass' is actually plated aluminium so daren't go mad on that.

   

I'm sure that the speaker is shot. I've tried playing various things through it, ancient and modern, and they all sound poor. What's actually up with it I don't know. The bellows are still stuck and the coil doesn't feel like it's rubbing. The back is more closed in than on most which doesn't make investigation easy.

At least I'm having a better time with this than Alan is with its grand-dad!

- Joe

[AlanBeckett]

Joe,
The back of the speaker - chassis - is more enclosed than a lot I've seen - see attached.
As I said before, it might be said to be a little shrill, but entirely acceptable.
Alan

   

[Joe]

This isn't shrill so much as distorted. The R33 plays fine, if a little shrilly, through other speakers and this speaker is lousy on anything. Its being enclosed makes examination difficult.

However, there are other things to deal with first, the wave switch being the biggest potential problem.

- Joe

[Joe]

"Irk the Purists - it's a right good laugh" - Half Man, Half Biscuit.

   

[Joe]

I knew I shouldn't have laughed at Alan last night as the Gods of Pye are judging me and the R33 has stopped singing.

It was after fitting the dial lights, it still doesn't work with them removed. There have been no flashes, bangs or puffs of smoke.

The voltages (digital) are:-

AC going into diode = 195V, should be 207V
DC coming out of diode = 229V, should be 225V

V1 UCH81 Triode/Heptode
Pin 1 (g2+g4) = 5V, should be 33V
Pin 6 (a) = 186V, should be 192V
Pin 8 (a") = 16V, should be 84V

V2 UBF89 Double Diode/Pentode
Pin 1 (g2) = 6V, should be 33V
Pin 6 (a) = 186, should be 192V

V3 Triode/Pentode
Pin 1 (a") = 68V, should be 70V
Pin 6 (a) = 220V, should be 217V
Pin 7 (k) = 10.4V, should be 10.4V
Pin 8 (g2) = 186V, should be 192V

All the components I've checked seem OK, including the transformers, so I can only think I've disturbed something or there's a solder-blob somewhere. The output stage is working but there's NO sound coming from the speaker when the wave switch is operated.

Any clues as to where to look next would be appreciated.

- Joe

[AlanBeckett]

Dial Lights, what Dial Lights?
I'm pretty sure mine hasn't got any, and the Schematic doesn't show any. No wonder it's stopped working if you've been bodging some in, you've upset it.
Anyway, the IF Frequency is 470kHz and you have a Signal Generator and a 'scope, so start using them.
Injecting some af into the top of the volume control is a good starting point - don't forget a capacitor in series. Then work backwards.
Alan

[Mark R]

I would be looking around C21 (electrolytic), C6, C7 R2 and R6. The voltages everywhere else look ok, Just the grids of V1 and 2 are down. I used the manufactures sheet which does not show any dial lamps.

cheers Mark

Edit crossed with Alan re dial lights