Help to identify mystery Pye radio (model QU) - UK Vintage Radio Repair and Restoration Discussion Forum

6.3volts · 3rd Sep 2017, 4:32 pm

Just found this on a car-boot sale.
Any suggestions as to the model number?
I've trawled extensively including google images but no clues so far.
It looks original apart from the smoothing caps
AC/DC set , LW/MW. I think the permanent magnet speaker is original as there is a smoothing choke and an o/put transformer on the power chassis.
Valves are CCH35, EF39?, CBL31, CY31.
It's in a poor state but I'm tempted to restore it as it's survived this far and it would be an excuse to learn to veneer the cabinet.

Ancient Geek · 3rd Sep 2017, 4:40 pm

Is it a model QU? http://www.radiomuseum.org/r/pye_qu.html

AC/HL · 3rd Sep 2017, 10:47 pm

Looks like it: http://www.service-data.com/section.php/6738/1/qu-1940

paulsherwin · 3rd Sep 2017, 11:24 pm

As you say, it's a bit of a wreck, but it's an interesting and relatively rare set so I hope you succeed with the cabinet restoration. Electronically it seems to be an example of the short superhet design so beloved of Pye in the 40s and 50s.

6.3volts · 4th Sep 2017, 7:41 am

Thanks for the input guys. Yes it's a 'QU'. I missed this because I first checked the manufacturer's data on my data cd and it shows a completely different circuit.
As a result I stopped looking at listings for 'QU'.
So far the valves look to be performing well so next I'll check the o/put and choke windings and hope they don't need a rewind.
I have a lot going on atm but will update this as and when I make progress.

Jonathan

6.3volts · 5th Sep 2017, 6:31 pm

Latest update. I've stripped out the case in order to treat the worm. I tend to do this with sets even if I have no plans to restore them. The EF39 has air in it but the others look very good. A few pics just for interest. I hope to be able to remove the knobs when the penetrating oil has softened up the rust on the screws, in the meantime I'll see if I can remove the rasping rust from the speaker magnet. This sometimes works and as it's a nice unit it's worth a go.

6.3volts · 8th Sep 2017, 10:16 am

This is probably on page 2 of the beginner's giude but it might help.
I removed two of the three knobs holding the front moulding on but the tuner knob in the centre was not giving way even with a two day soak in oil.
I could feel the slot on the grub screw beginning to twist off so I stopped that approach and tried heat.
The knob looks like bakelite with the screw thread cut directly in the body. In my other life as an engineer I often use heat to break the grip of rusted parts so thought I'd give it a try. I left a hot soldering iron in gravity contact with the visible end of the screw for about 45 mins and then allowed it to cool.
I was surprised at how little resistance the screw put up as I effortlessly unscrewed it and the female thread seems undamaged.
The printed scale has cleaned up perfectly and I'm working my way through the power supply as the wire insulation is largely shot and some previous work sets a high standard in the 'bodge' category. I'll also be re-creating a capacitor block for visual effect and hope to show pics as I go.
Jonathan.

6.3volts · 9th Sep 2017, 4:06 pm

Update on the capacitor block.
I made an alloy base to match the original mounting marks and glued this into the base of the card box made from a Stella pack (other beers are available). I find this strong card to be ideal for these projects. Next stage will be to move on to the receiver chassis and I'll start by checking the condition if the two I F transformers. This set has been damp and I can expect to check every detail of insulation and continuity.

Jonathan.

6.3volts · 9th Sep 2017, 4:17 pm

I've taken one IF transformer apart and found a slight problem. Tuning is by iron slug and the iron looks to have been bonded on to a plastic screw. One slug was loose in its tube but the other one has gone.
I fixed the slug back on but would like advice on using ferrite as a substitute for the iron. I have nothing like it but have lots of ferrite. Can I expect a replacement slug of ferrite to work in the same way? Otherwise what about brass? I don't mind adding a few pf. to bring the tuning in line. Any advice welcome.
Jonathan

6.3volts · 23rd Sep 2017, 11:27 am

Latest update. The chassis is more or less done. A lot of the usual failed components- including one high resistor and a lot of bad wire insulation. The entire unbilical was rotten as was the screened cable to EF39.
At first there was nothing from the speaker and I found that although the CCH35 tested well it refused to oscillate. An ECH35 substitute runs very well. The heater currents are close and everything seems to be happy with the fillament train.
The main problem I've had with this set is the I.F. frequency which was running at 520khz instead of the rated 467khz and the 2 I.F.'s were both adjusted to suit this. By the time I'd worked through all the set's problems I was left suspecting the mica caps on the windings may be bad. They test good so I am left thinking that the cores may not be correct but I'm guessing. To make some progress I decided to add some bee-hives and I now have the set performing well. It suffers from a lack of a triode AF stage but with a good antenna sounds good with reasonable selectivity so I'm calling it done.
Next is the case and I'll start with making a new window for the dial. The original is tobacco coloured with some tragic evidence of past cleaning with a brillo pad. The printed scale has cleaned up very well and I'm hoping that when the cabinet is done I'll have a 'looker'. The pics are part of the story and the scope screen was me double checking the IF. by comparing it to a known signal.

Boater Sam · 23rd Sep 2017, 1:45 pm

Ferrite slug should work but may need a trimmer to bring it in range. Brass will lower the frequency, I used to have a magic stick which was brass one end and ferrite to other. It was used to poke into an IF core to see which way it needed padding to get the frequency correct. I believe they were sold as "tuning Wand" but its been a while!

G6Tanuki · 23rd Sep 2017, 1:52 pm

Those IFTs are the same as used in WWII-era 18/19-sets and the Pye PCR. The coming-unglued-followed-by-disappearance-of-the-core is a well known problem. In the past I've filed off the little 'pip' from the plastic thing then drilled/tapped a hole right through to take the brass spindle from one of the tuning-slugs that are a lump of ferrite on a brass stud.

Screw the plastic thing into the IFT all the way, melt some wax around its thread to hold it in place, then use the thread of the brass slug to do the adjustment. When it's right run a nut down the exposed brass thread to stop it moving, then another smidgin of wax on top to make it look right.

3rd Sep 2017, 4:32 pm	#1
6.3volts Pentode Join Date: Nov 2009 Location: Welshpool, Powys, UK. Posts: 121	Help to identify mystery Pye radio (model QU) Just found this on a car-boot sale. Any suggestions as to the model number? I've trawled extensively including google images but no clues so far. It looks original apart from the smoothing caps AC/DC set , LW/MW. I think the permanent magnet speaker is original as there is a smoothing choke and an o/put transformer on the power chassis. Valves are CCH35, EF39?, CBL31, CY31. It's in a poor state but I'm tempted to restore it as it's survived this far and it would be an excuse to learn to veneer the cabinet. Attached Thumbnails Last edited by 6.3volts; 3rd Sep 2017 at 4:41 pm.

3rd Sep 2017, 4:40 pm	#2
Ancient Geek Retired Dormant Member Join Date: Aug 2017 Location: Bristol, UK. Posts: 136	Re: Help to identify mystery Pye radio. Is it a model QU? http://www.radiomuseum.org/r/pye_qu.html

3rd Sep 2017, 10:47 pm	#3
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Help to identify mystery Pye radio. Looks like it: http://www.service-data.com/section.php/6738/1/qu-1940

3rd Sep 2017, 11:24 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,936	Re: Help to identify mystery Pye radio. As you say, it's a bit of a wreck, but it's an interesting and relatively rare set so I hope you succeed with the cabinet restoration. Electronically it seems to be an example of the short superhet design so beloved of Pye in the 40s and 50s.

4th Sep 2017, 7:41 am	#5
6.3volts Pentode Join Date: Nov 2009 Location: Welshpool, Powys, UK. Posts: 121	Re: Help to identify mystery Pye radio. Thanks for the input guys. Yes it's a 'QU'. I missed this because I first checked the manufacturer's data on my data cd and it shows a completely different circuit. As a result I stopped looking at listings for 'QU'. So far the valves look to be performing well so next I'll check the o/put and choke windings and hope they don't need a rewind. I have a lot going on atm but will update this as and when I make progress. Jonathan

5th Sep 2017, 6:31 pm	#6
6.3volts Pentode Join Date: Nov 2009 Location: Welshpool, Powys, UK. Posts: 121	Re: Help to identify mystery Pye radio (model QU) Latest update. I've stripped out the case in order to treat the worm. I tend to do this with sets even if I have no plans to restore them. The EF39 has air in it but the others look very good. A few pics just for interest. I hope to be able to remove the knobs when the penetrating oil has softened up the rust on the screws, in the meantime I'll see if I can remove the rasping rust from the speaker magnet. This sometimes works and as it's a nice unit it's worth a go. Attached Thumbnails

8th Sep 2017, 10:16 am	#7
6.3volts Pentode Join Date: Nov 2009 Location: Welshpool, Powys, UK. Posts: 121	Re: Help to identify mystery Pye radio (model QU) This is probably on page 2 of the beginner's giude but it might help. I removed two of the three knobs holding the front moulding on but the tuner knob in the centre was not giving way even with a two day soak in oil. I could feel the slot on the grub screw beginning to twist off so I stopped that approach and tried heat. The knob looks like bakelite with the screw thread cut directly in the body. In my other life as an engineer I often use heat to break the grip of rusted parts so thought I'd give it a try. I left a hot soldering iron in gravity contact with the visible end of the screw for about 45 mins and then allowed it to cool. I was surprised at how little resistance the screw put up as I effortlessly unscrewed it and the female thread seems undamaged. The printed scale has cleaned up perfectly and I'm working my way through the power supply as the wire insulation is largely shot and some previous work sets a high standard in the 'bodge' category. I'll also be re-creating a capacitor block for visual effect and hope to show pics as I go. Jonathan.

9th Sep 2017, 4:06 pm	#8
6.3volts Pentode Join Date: Nov 2009 Location: Welshpool, Powys, UK. Posts: 121	Re: Help to identify mystery Pye radio (model QU) Update on the capacitor block. I made an alloy base to match the original mounting marks and glued this into the base of the card box made from a Stella pack (other beers are available). I find this strong card to be ideal for these projects. Next stage will be to move on to the receiver chassis and I'll start by checking the condition if the two I F transformers. This set has been damp and I can expect to check every detail of insulation and continuity. Jonathan. Attached Thumbnails

9th Sep 2017, 4:17 pm	#9
6.3volts Pentode Join Date: Nov 2009 Location: Welshpool, Powys, UK. Posts: 121	Re: Help to identify mystery Pye radio (model QU) I've taken one IF transformer apart and found a slight problem. Tuning is by iron slug and the iron looks to have been bonded on to a plastic screw. One slug was loose in its tube but the other one has gone. I fixed the slug back on but would like advice on using ferrite as a substitute for the iron. I have nothing like it but have lots of ferrite. Can I expect a replacement slug of ferrite to work in the same way? Otherwise what about brass? I don't mind adding a few pf. to bring the tuning in line. Any advice welcome. Jonathan Attached Thumbnails

23rd Sep 2017, 11:27 am	#10
6.3volts Pentode Join Date: Nov 2009 Location: Welshpool, Powys, UK. Posts: 121	Re: Help to identify mystery Pye radio (model QU) Latest update. The chassis is more or less done. A lot of the usual failed components- including one high resistor and a lot of bad wire insulation. The entire unbilical was rotten as was the screened cable to EF39. At first there was nothing from the speaker and I found that although the CCH35 tested well it refused to oscillate. An ECH35 substitute runs very well. The heater currents are close and everything seems to be happy with the fillament train. The main problem I've had with this set is the I.F. frequency which was running at 520khz instead of the rated 467khz and the 2 I.F.'s were both adjusted to suit this. By the time I'd worked through all the set's problems I was left suspecting the mica caps on the windings may be bad. They test good so I am left thinking that the cores may not be correct but I'm guessing. To make some progress I decided to add some bee-hives and I now have the set performing well. It suffers from a lack of a triode AF stage but with a good antenna sounds good with reasonable selectivity so I'm calling it done. Next is the case and I'll start with making a new window for the dial. The original is tobacco coloured with some tragic evidence of past cleaning with a brillo pad. The printed scale has cleaned up very well and I'm hoping that when the cabinet is done I'll have a 'looker'. The pics are part of the story and the scope screen was me double checking the IF. by comparing it to a known signal. Attached Thumbnails

23rd Sep 2017, 1:45 pm	#11
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Help to identify mystery Pye radio (model QU) Ferrite slug should work but may need a trimmer to bring it in range. Brass will lower the frequency, I used to have a magic stick which was brass one end and ferrite to other. It was used to poke into an IF core to see which way it needed padding to get the frequency correct. I believe they were sold as "tuning Wand" but its been a while!

23rd Sep 2017, 1:52 pm	#12
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,996	Re: Help to identify mystery Pye radio (model QU) Those IFTs are the same as used in WWII-era 18/19-sets and the Pye PCR. The coming-unglued-followed-by-disappearance-of-the-core is a well known problem. In the past I've filed off the little 'pip' from the plastic thing then drilled/tapped a hole right through to take the brass spindle from one of the tuning-slugs that are a lump of ferrite on a brass stud. Screw the plastic thing into the IFT all the way, melt some wax around its thread to hold it in place, then use the thread of the brass slug to do the adjustment. When it's right run a nut down the exposed brass thread to stop it moving, then another smidgin of wax on top to make it look right.