Irish Pye PJ 0255 Radio - UK Vintage Radio Repair and Restoration Discussion Forum

sotatech · 8th Jul 2021, 8:41 am

I am having trouble finding any information on this 5 valve (plus EM81 magic eye) radio. It's in really nice condition externally so it's worth saving. On the back cover it says "REF No. PJ 0255" which I am assuming is the model number?

I appears similar to a Pye PJ508 and all the valves are the same, although the internal layout is different.

The problems I'm having are as follows:

1. No sound, this is due to an open circuit on the input side of the AF transformer. It seems to be a centre tapped winding and the open is from the centre tap to one side. Shorting it out (briefly!), produces a loud hum. Can anyone suggest a replacement or even if it can be repaired?

2. Capacitors! Most of the Hunts and wax caps are easily identified and I have ordered replacements, but there is one Hunts cap from the wiper of the tone control to ground that has disintegrated. Any thoughts on likley values for this?

3. It looks like it has been "repaired" previously, with a couple of the coils showing evidence of adjustment, so an alignment guide would be useful.

Thanks!

Silicon · 8th Jul 2021, 11:47 pm

The AF transformer may not be 'centre tapped'. That has a precise meaning.

It was very common to have a hum reduction winding connected to the primary winding of the output transformer.

Can you measure the DC resistance of the winding that still works?

Knowing the ratio of the working winding in comparison with the output winding would also be useful.

If the impedance of the speaker is known, it should not be too difficult to find an output transformer to work with the EL84 output valve.

sotatech · 9th Jul 2021, 12:41 pm

Thanks for the reply, it's been about 40 years since I did any work on valve equipment so apologies for the lack of precision! However, your mention of the hum reduction winding rang a bell with me and I do recall working on radios previously with this feature.

The working portion of the primary measures 390 ohms. The transformer measures about 6.5cm between the mounting lugs and 6cm in height. There are no identifying markings on it.
I also can't see any markings on the speaker, but its resistance measures around 3 ohms.

8th Jul 2021, 8:41 am	#1
sotatech Diode Join Date: Jul 2021 Location: Galway, County Galway, Ireland. Posts: 4	Irish Pye PJ 0255 Radio I am having trouble finding any information on this 5 valve (plus EM81 magic eye) radio. It's in really nice condition externally so it's worth saving. On the back cover it says "REF No. PJ 0255" which I am assuming is the model number? I appears similar to a Pye PJ508 and all the valves are the same, although the internal layout is different. The problems I'm having are as follows: 1. No sound, this is due to an open circuit on the input side of the AF transformer. It seems to be a centre tapped winding and the open is from the centre tap to one side. Shorting it out (briefly!), produces a loud hum. Can anyone suggest a replacement or even if it can be repaired? 2. Capacitors! Most of the Hunts and wax caps are easily identified and I have ordered replacements, but there is one Hunts cap from the wiper of the tone control to ground that has disintegrated. Any thoughts on likley values for this? 3. It looks like it has been "repaired" previously, with a couple of the coils showing evidence of adjustment, so an alignment guide would be useful. Thanks!

8th Jul 2021, 11:47 pm	#2
Silicon Nonode Join Date: Jun 2007 Location: Coulsdon, London, UK. Posts: 2,169	Re: Irish Pye PJ 0255 Radio The AF transformer may not be 'centre tapped'. That has a precise meaning. It was very common to have a hum reduction winding connected to the primary winding of the output transformer. Can you measure the DC resistance of the winding that still works? Knowing the ratio of the working winding in comparison with the output winding would also be useful. If the impedance of the speaker is known, it should not be too difficult to find an output transformer to work with the EL84 output valve.

9th Jul 2021, 12:41 pm	#3
sotatech Diode Join Date: Jul 2021 Location: Galway, County Galway, Ireland. Posts: 4	Re: Irish Pye PJ 0255 Radio Thanks for the reply, it's been about 40 years since I did any work on valve equipment so apologies for the lack of precision! However, your mention of the hum reduction winding rang a bell with me and I do recall working on radios previously with this feature. The working portion of the primary measures 390 ohms. The transformer measures about 6.5cm between the mounting lugs and 6cm in height. There are no identifying markings on it. I also can't see any markings on the speaker, but its resistance measures around 3 ohms.