Pye SP/AC - UK Vintage Radio Repair and Restoration Discussion Forum

kestrelmusic · 18th Jun 2020, 9:40 pm

I'm working on a Pye SP/AC at the moment. It's all but derelict but I got the first squawk out of it today. The IF alignment was all over the place - it was peaking, for want of a better word, at around 108kc/s - according to Trader it should be 127! And aligning the first IFT really needs a dwarf with triple-jointed elbows and a plastic screwdriver... However, it is now working after a fashion, but will need a good bit more done.

But... it needs a new dial. Does anyone by any chance have either a SP/AC or a SP/B (which I think is the same model except for the power supply) that could send me a reasonably clear picture of the dial?

kestrelmusic · 20th Jun 2020, 6:57 pm

Well, the set is now working, but the internal moving coil speaker is definitely duff. A modern speaker in parallel produces a pleasing sound, and the energizing coil shows around the right DC resistance, but all I get is a very quiet and 'rattly' sound. I assume this is due to some internal part, probably corroded, making contact with some other internal part from which it should be separated.

However, I've never taken one of these to pieces, so should be grateful if a kind person, or some kind people, could either offer advice on doing so and/or point me in the direction of some helpful information.

crackle · 20th Jun 2020, 8:02 pm

These old speakers are normally easy to service. particularly if they do not have a permanent magnet.
How about some photos of the speaker and radio.

Mike

kestrelmusic · 22nd Jun 2020, 4:57 pm

I've stripped the speaker, to find that the speech coil has come away from the cone and partly uncoiled itself. There are a few shreds of some kind of papery material which I assume was the coil former and was attached to the cone. Unfortunately this set has got very damp, if not actually wet, at some time; there is a lot of rust on steel parts (including the speaker basket) and marks of water damage on the case and I suspect that long term storage in a damp condition has caused the former to disintegrate.

I will have a go at re-winding it, but I am not sure how successful it will be. I may end up putting a modern (well, 1970s) permanent magnet speaker in its place and using a separate HT choke instead of the field coil.

kestrelmusic · 27th Jun 2020, 2:26 pm

Update - the speaker was knackered. The celluloid (?) tube joining the cone to the speech coil just crumbled to dust, and the cone itself was not much better. I've replaced it with a good modern (well, 1970s) speaker and hidden a big choke inside the PSU to replace the field coil. Pictures and rebuild description in the "success stories" group.

18th Jun 2020, 9:40 pm	#1
kestrelmusic Hexode Join Date: Feb 2008 Location: Wrexham, North Wales, UK. Posts: 466	Pye SP/AC I'm working on a Pye SP/AC at the moment. It's all but derelict but I got the first squawk out of it today. The IF alignment was all over the place - it was peaking, for want of a better word, at around 108kc/s - according to Trader it should be 127! And aligning the first IFT really needs a dwarf with triple-jointed elbows and a plastic screwdriver... However, it is now working after a fashion, but will need a good bit more done. But... it needs a new dial. Does anyone by any chance have either a SP/AC or a SP/B (which I think is the same model except for the power supply) that could send me a reasonably clear picture of the dial?

20th Jun 2020, 6:57 pm	#2
kestrelmusic Hexode Join Date: Feb 2008 Location: Wrexham, North Wales, UK. Posts: 466	Re: Pye SP/AC Well, the set is now working, but the internal moving coil speaker is definitely duff. A modern speaker in parallel produces a pleasing sound, and the energizing coil shows around the right DC resistance, but all I get is a very quiet and 'rattly' sound. I assume this is due to some internal part, probably corroded, making contact with some other internal part from which it should be separated. However, I've never taken one of these to pieces, so should be grateful if a kind person, or some kind people, could either offer advice on doing so and/or point me in the direction of some helpful information.

20th Jun 2020, 8:02 pm	#3
crackle Rest in Peace Join Date: Mar 2011 Location: Basildon, Essex, UK. Posts: 4,100	Re: Pye SP/AC These old speakers are normally easy to service. particularly if they do not have a permanent magnet. How about some photos of the speaker and radio. Mike

22nd Jun 2020, 4:57 pm	#4
kestrelmusic Hexode Join Date: Feb 2008 Location: Wrexham, North Wales, UK. Posts: 466	Re: Pye SP/AC I've stripped the speaker, to find that the speech coil has come away from the cone and partly uncoiled itself. There are a few shreds of some kind of papery material which I assume was the coil former and was attached to the cone. Unfortunately this set has got very damp, if not actually wet, at some time; there is a lot of rust on steel parts (including the speaker basket) and marks of water damage on the case and I suspect that long term storage in a damp condition has caused the former to disintegrate. I will have a go at re-winding it, but I am not sure how successful it will be. I may end up putting a modern (well, 1970s) permanent magnet speaker in its place and using a separate HT choke instead of the field coil.

27th Jun 2020, 2:26 pm	#5
kestrelmusic Hexode Join Date: Feb 2008 Location: Wrexham, North Wales, UK. Posts: 466	Re: Pye SP/AC Update - the speaker was knackered. The celluloid (?) tube joining the cone to the speech coil just crumbled to dust, and the cone itself was not much better. I've replaced it with a good modern (well, 1970s) speaker and hidden a big choke inside the PSU to replace the field coil. Pictures and rebuild description in the "success stories" group.