This radio was given to me along with two others. It's owner was clearing out his garage and needed someone to take it away.

The Pye P76 was first sold in July 1953 at a price of just over £19.

It looked like it hadn't been used in a very long time, there was a lot of dust and spiders webs inside the case (the outside of the case wasn't much better). The valves all seemed original and there hadn't been any nasty repairs.

I replaced the AF coupling capacitor C28 (just as a precaution - these capacitors are supposed to isolate DC from the output valve grid. If they go faulty then the output valve draws too much current through the output transformer and can make a real mess) and also the mains lead.

On inspection of the chassis I found that one end of R5 (Oscillator anode feed resistor) had become disconnected. The wire that was connecting it looked like it had broken (strange ??). I connected it back up, as without this the oscillator part of the frequency changer valve, the radio wouldn't have worked.

Both the dial lamps were blown and I also replaced these. This is always a good idea - it's a reminder that the power is ON when working at the set and it also makes me feel like I'm making progress.

Using a home made power supply, I brought up the HT slowly (through a 10K resistor) and all seemed fine. None of the capacitors were drawing too much current.

Using a variac, I then powered up the set with just the rectifier valve in circuit and all seemed OK.

Then I put the rest of the valves back in and waited for them to heat up. I was rewarded with a (very) faint hum from the speaker and no audio. All the wavebands were all dead, I switched the set to its "GRAM" setting, to see if the AF stage was working. I checked there was no voltage present (better safe than sorry) and then touched the Pickup input. There should have been a loud hum, but again nothing but the original faint hum. Also there was no clicking sound from the speaker when the switch was rotated (which would have been normal). Calling the radio bad names didn't make any difference either.

Click here for a circuit diagram

When I connected my oscilloscope to the volume control wiper I could see an audio waveform. On longwave I could tune across the band and "see" the two big signals that usually come in well here (Atlantic 252 and BBC Radio 4). This audio signal travelled as far as the grid on V3, but didn't make an appearance at it's anode. I checked the voltages around V3 (EBC 41) and they all seemed fine, so I took the valve out of the set and tried it in another old radio. The valve worked fine in the other radio, but still refused to amplify in the P76. Gently tapping the valve produced click sounds from the speaker, so I took it back out and cleaned it's pins and sprayed contact cleaner into it's socket - still no joy. I then tried a replacement valve, which worked fine first time. I'll have to get this valve tested sometime to see what's wrong with it.

Rear view

The quality of sound produced from this old radio is fantastic, it's high purchase price when new reflects the fact that it wasn't a budget piece of kit. It has lovely slow motion tuning, with a flywheel behind the tuning knob

CLICK HERE TO HEAR THE RADIO WORKING !

Don't forget that there are lethal high voltages in old valve equipment, don't even take the back off an old radio if you don't know how to deal with these. Do as much work as possible with the power OFF. If you have to make adjustments or take readings with power applied, be VERY careful. Use insulated tools and only use one hand (so if you do touch something you may avoid putting yourself in the unfortunate position where electrical current flows from one hand to another, though your heart). Beware capacitors that hold high voltage charges even when equipment is disconnected from the mains.

On a more positive note, valve radios aren't hard to fix and they make nice useable "furniture" for your home. They will still work after a nuclear bomb goes off near your house (solid state equipment is damaged by the huge electromagnetic pulse). Someday they might be worth a lot of money, so the more old radios you have the richer you'll be (I'll be a millionaire !)