Pye MM - UK Vintage Radio Repair and Restoration Discussion Forum

Desmond · 24th Jun 2016, 12:58 pm

Having aquired this PYE MM (see pictures) through a swap at the Dutch vintage radio jumble and having read the various postings on this model on the forum, I would like to know if the article in Radiophile 114 is a helpful source of further info.
I have not dismantled anything yet, so at the moment I can not tell if it suffers from the dreaded disintegration of metal parts.
Anyway, I have enjoyed reading the article Sickness caused by an old PYE by Steve Harris!
If it is as bad as the ones he tackled I might be tempted to leave it as it is.
But the goal will be to get it working again.

Thank you very much in advance,
with kind regards,
Desmond

Ed_Dinning · 25th Jun 2016, 12:26 pm

Hi Desmond, they are quite nice sets and work pretty well. Beware of the monkey metal tuning caps. They can be easily turned to dust! They can be stabilised using superglue.
On my models most of the caps were not too bad, but the resistors were well out, fortunately I have a good selection of spare dog bone types.

Good luck, Ed

Desmond · 26th Jun 2016, 3:33 pm

Hi Ed,
many thanks for your tip regarding stabilizing the monkey metal parts and resistors

So far I have taken the powersupply chassis out of the cabinet and have checked for capacity and leakage of the square capacitor box with a digital handheld meter and AVO8, both seem te be ok, no leakage at 15V testvoltage.
At work I have access to a Megohmmeter (up to 1000V DC testvoltage in steps of 1V),
that will show up leakage better at higher voltage.

The electrolytic capacitor is bone dry as can be expected after over 80 years!

Thanks again Ed,
with kind regards,
Desmond

Ed_Dinning · 27th Jun 2016, 10:50 am

Hi Desmond, in my case the tin box was fine also, but the e-cap was, as yours, dried out.
The meter, set to operating voltage should test the rest of the caps well, some small leakage will be OK, check the circuit resistance associated with the cap to see if this will cause any problems.
It will need a long wire aerial, but should perform well.

Ed

24th Jun 2016, 12:58 pm	#1
Desmond Triode Join Date: Dec 2009 Location: Voorburg, near the Hague- Netherlands Posts: 18	Pye MM Having aquired this PYE MM (see pictures) through a swap at the Dutch vintage radio jumble and having read the various postings on this model on the forum, I would like to know if the article in Radiophile 114 is a helpful source of further info. I have not dismantled anything yet, so at the moment I can not tell if it suffers from the dreaded disintegration of metal parts. Anyway, I have enjoyed reading the article Sickness caused by an old PYE by Steve Harris! If it is as bad as the ones he tackled I might be tempted to leave it as it is. But the goal will be to get it working again. Thank you very much in advance, with kind regards, Desmond Attached Thumbnails

25th Jun 2016, 12:26 pm	#2
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Pye MM Hi Desmond, they are quite nice sets and work pretty well. Beware of the monkey metal tuning caps. They can be easily turned to dust! They can be stabilised using superglue. On my models most of the caps were not too bad, but the resistors were well out, fortunately I have a good selection of spare dog bone types. Good luck, Ed

26th Jun 2016, 3:33 pm	#3
Desmond Triode Join Date: Dec 2009 Location: Voorburg, near the Hague- Netherlands Posts: 18	Re: Pye MM Hi Ed, many thanks for your tip regarding stabilizing the monkey metal parts and resistors So far I have taken the powersupply chassis out of the cabinet and have checked for capacity and leakage of the square capacitor box with a digital handheld meter and AVO8, both seem te be ok, no leakage at 15V testvoltage. At work I have access to a Megohmmeter (up to 1000V DC testvoltage in steps of 1V), that will show up leakage better at higher voltage. The electrolytic capacitor is bone dry as can be expected after over 80 years! Thanks again Ed, with kind regards, Desmond

27th Jun 2016, 10:50 am	#4
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Pye MM Hi Desmond, in my case the tin box was fine also, but the e-cap was, as yours, dried out. The meter, set to operating voltage should test the rest of the caps well, some small leakage will be OK, check the circuit resistance associated with the cap to see if this will cause any problems. It will need a long wire aerial, but should perform well. Ed