Rejuvenating volume pots. - UK Vintage Radio Repair and Restoration Discussion Forum

Vespaman · 10th Nov 2006, 2:32 pm

Some advice please from all you experts out there.

My Ferranti U1015 has a really dodgy volume control (1meg); noisy and switch not fully working. Rather than try to dismantle the thing I will buy a new one. One site has what I need but it lists two types: log-law and linear law. Which should I use and what is the difference?

Paul_RK · 10th Nov 2006, 2:39 pm

Always log for volume controls. The resistance of the track is distributed logarithmically, with the result that when using the control you have the impression that volume increases in linear fashion. I'd still put in a word for prising the thing apart, cleaning it up and seeing what happens, though: you know the existing control fits, and you'll be fortunate indeed if you can find a replacement that doesn't need adapting in one way or another.

Regards,
Paul

paulsherwin · 10th Nov 2006, 2:48 pm

I agree with Paul, try dismantling the old one. It usually isn't too difficult and once you have it apart you can clean the carbon track properly. There's nothing to lose - you can always buy a replacement later. Modern pots aren't easy to track down with these values, and will always look wrong.

Paul

Vespaman · 10th Nov 2006, 11:14 pm

Thanks, guys. I'll have a bash at dismantling the thing, I did one many moons ago and I remember it was not too challenging.

Mike Phelan · 11th Nov 2006, 9:31 am

The problem is often tarnish on the ring of the wiper contact, not the actual track. Nothing that a bit of Brasso on a Q-tip won't cure.

The spindle will come out if you spread the circlip - put thick grease on it and clean and tension the contacts.

Early pots usually last for years if they are not burnt.

Vespaman · 14th Nov 2006, 9:39 am

Thanks for the sage advice all you experts. I dismantled the pot yesterday, not that easy as the plastic and metal parts were a very tight fit. Nevertheless once the years of gunge were removed the radio is back to full health.

10th Nov 2006, 2:32 pm	#1
Vespaman Retired Dormant Member Join Date: Oct 2005 Location: Reading, Berkshire, UK. Posts: 21	Rejuvenating volume pots. Some advice please from all you experts out there. My Ferranti U1015 has a really dodgy volume control (1meg); noisy and switch not fully working. Rather than try to dismantle the thing I will buy a new one. One site has what I need but it lists two types: log-law and linear law. Which should I use and what is the difference? Last edited by Darren-UK; 3rd Aug 2007 at 1:26 am. Reason: Make/model added to text.

10th Nov 2006, 2:39 pm	#2
Paul_RK Dekatron Join Date: Nov 2003 Location: Fakenham, Norfolk, UK. Posts: 4,255	Re: My Ferranti u1015 Always log for volume controls. The resistance of the track is distributed logarithmically, with the result that when using the control you have the impression that volume increases in linear fashion. I'd still put in a word for prising the thing apart, cleaning it up and seeing what happens, though: you know the existing control fits, and you'll be fortunate indeed if you can find a replacement that doesn't need adapting in one way or another. Regards, Paul

10th Nov 2006, 2:48 pm	#3
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,936	Re: My Ferranti u1015 I agree with Paul, try dismantling the old one. It usually isn't too difficult and once you have it apart you can clean the carbon track properly. There's nothing to lose - you can always buy a replacement later. Modern pots aren't easy to track down with these values, and will always look wrong. Paul

10th Nov 2006, 11:14 pm	#4
Vespaman Retired Dormant Member Join Date: Oct 2005 Location: Reading, Berkshire, UK. Posts: 21	Re: My Ferranti u1015 Thanks, guys. I'll have a bash at dismantling the thing, I did one many moons ago and I remember it was not too challenging.

11th Nov 2006, 9:31 am	#5
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: My Ferranti u1015 The problem is often tarnish on the ring of the wiper contact, not the actual track. Nothing that a bit of Brasso on a Q-tip won't cure. The spindle will come out if you spread the circlip - put thick grease on it and clean and tension the contacts. Early pots usually last for years if they are not burnt. __________________ Mike.

14th Nov 2006, 9:39 am	#6
Vespaman Retired Dormant Member Join Date: Oct 2005 Location: Reading, Berkshire, UK. Posts: 21	Re: My Ferranti u1015 Thanks for the sage advice all you experts. I dismantled the pot yesterday, not that easy as the plastic and metal parts were a very tight fit. Nevertheless once the years of gunge were removed the radio is back to full health.