Faulty on/off volume pot on a Hacker GP42 - UK Vintage Radio Repair and Restoration Discussion Forum

PJay1966 · 13th Jun 2021, 10:33 am

Hi there everyone.

I have found that the on/off volume pot (RV1) on my GP42 is faulty, the player is powered up as soon as its switched on from the mains and the on/off on the player doesn't do anything. The volume control works fine however but the pot feels very rough when turned. I have given it a good blast of Servisol but its made no difference. Is it possible to replace it and if so I would be hugely grateful for some advice on what and where to buy one.

Thanks for any help on this!

Paul

raditechman · 13th Jun 2021, 11:11 am

I think it is a 1 M ohm potentiometer (volume control) with switch.

Not so easy to find now

I do not know the size and length of the shaft in the Hacker but here is a link to one supplier. Not sure if they still supply UK now.

https://www.tundtmusic.com/Potentiom...ml?language=en

I am sure that some other members will be able to give you more advice.

You will need to solder in the new part.

John

Station X · 13th Jun 2021, 11:11 am

These can be repaired. See here:-

https://www.vintage-radio.net/forum/...0&postcount=36

PJay1966 · 13th Jun 2021, 12:14 pm

Thanks guys appreciate the info.

I think the shaft on the one of that website looks too short, I need to remove the tone control unit from the player to have a proper look. I guess my only option would be to try and fix it, I'll have a crack at that when I have a few hours spare...

Edward Huggins · 13th Jun 2021, 2:43 pm

You have 2 options - either leave as is and disconnect from the mains when not in use or fit a new/rebuilt pot. If fitting a new potentiometer there is more to this than you may think in terms of sourcing the correct 1meg DPSW component, adjusting the shaft size and removal of the tone control sub-assembly. We assume you have the necessary soldering and electrical skills.

PJay1966 · 13th Jun 2021, 3:55 pm

Thanks Edward I am experienced with electronics although with a bias to amateur radio equipment. So I have no problem with the repair you suggest. I think for now though I’ll just enjoy using it and fix it when I get round to it!

Nuvistor · 13th Jun 2021, 11:29 pm

Would one of these do the job?
https://www.blore-ed.com/product-pag...-potentiometer

PJay1966 · 14th Jun 2021, 8:46 am

Looks like they can supply one thanks Frank! Just a question though do I need a linear or log type?

Nuvistor · 14th Jun 2021, 9:23 am

I would expect it to be log, but measure the old one to be sure.

Chiltern · 14th Jun 2021, 10:37 am

Quote:

Originally Posted by Nuvistor

Would one of these do the job?
https://www.blore-ed.com/product-pag...-potentiometer

I bought some last year following a post in 'where to get sets and parts' as they were on sale at the time. Yes, Log, you will need the metal shaft and imperial option. worked out well. Reduced the shaft length and machined a flat, job done.

I cannot remember, but there may be a minimum order charge, expect delivery and vat.

Alan

PaulR · 21st Jun 2021, 9:19 am

As StationX says these can be repaired. I have also had good results with crackly volume controls by cleaning the track then packing it with Vaseline. It is rather counter intuitive but I did it with a mid '30s radio several years ago and it still works perfectly. I got the idea from someone who said they pack it with Waxoyl but I would have thought that the thinner in that would evaporate leaving thick, hard wax.

I imagine that the silicone grease recommended for the switch would work as well as Vaseline on the track

PJay1966 · 21st Jun 2021, 2:45 pm

Thanks Paul

It’s fixed now and seems fine so far!

13th Jun 2021, 10:33 am	#1
PJay1966 Pentode Join Date: May 2021 Location: Buckinghamshire, UK. Posts: 133	Faulty on/off volume pot on a Hacker GP42 Hi there everyone. I have found that the on/off volume pot (RV1) on my GP42 is faulty, the player is powered up as soon as its switched on from the mains and the on/off on the player doesn't do anything. The volume control works fine however but the pot feels very rough when turned. I have given it a good blast of Servisol but its made no difference. Is it possible to replace it and if so I would be hugely grateful for some advice on what and where to buy one. Thanks for any help on this! Paul

13th Jun 2021, 11:11 am	#2
raditechman Heptode Join Date: Feb 2007 Location: West London, UK. Posts: 867	Re: Faulty on/off volume pot on a Hacker GP42 I think it is a 1 M ohm potentiometer (volume control) with switch. Not so easy to find now I do not know the size and length of the shaft in the Hacker but here is a link to one supplier. Not sure if they still supply UK now. https://www.tundtmusic.com/Potentiom...ml?language=en I am sure that some other members will be able to give you more advice. You will need to solder in the new part. John

13th Jun 2021, 11:11 am	#3
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,286	Re: Faulty on/off volume pot on a Hacker GP42 These can be repaired. See here:- https://www.vintage-radio.net/forum/...0&postcount=36 __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

13th Jun 2021, 12:14 pm	#4
PJay1966 Pentode Join Date: May 2021 Location: Buckinghamshire, UK. Posts: 133	Re: Faulty on/off volume pot on a Hacker GP42 Thanks guys appreciate the info. I think the shaft on the one of that website looks too short, I need to remove the tone control unit from the player to have a proper look. I guess my only option would be to try and fix it, I'll have a crack at that when I have a few hours spare...

13th Jun 2021, 2:43 pm	#5
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,326	Re: Faulty on/off volume pot on a Hacker GP42 You have 2 options - either leave as is and disconnect from the mains when not in use or fit a new/rebuilt pot. If fitting a new potentiometer there is more to this than you may think in terms of sourcing the correct 1meg DPSW component, adjusting the shaft size and removal of the tone control sub-assembly. We assume you have the necessary soldering and electrical skills. __________________ Edward.

13th Jun 2021, 3:55 pm	#6
PJay1966 Pentode Join Date: May 2021 Location: Buckinghamshire, UK. Posts: 133	Re: Faulty on/off volume pot on a Hacker GP42 Thanks Edward I am experienced with electronics although with a bias to amateur radio equipment. So I have no problem with the repair you suggest. I think for now though I’ll just enjoy using it and fix it when I get round to it!

13th Jun 2021, 11:29 pm	#7
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,431	Re: Faulty on/off volume pot on a Hacker GP42 Would one of these do the job? https://www.blore-ed.com/product-pag...-potentiometer __________________ Frank

14th Jun 2021, 8:46 am	#8
PJay1966 Pentode Join Date: May 2021 Location: Buckinghamshire, UK. Posts: 133	Re: Faulty on/off volume pot on a Hacker GP42 Looks like they can supply one thanks Frank! Just a question though do I need a linear or log type?

14th Jun 2021, 9:23 am	#9
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,431	Re: Faulty on/off volume pot on a Hacker GP42 I would expect it to be log, but measure the old one to be sure. __________________ Frank

21st Jun 2021, 9:19 am	#11
PaulR Dekatron Join Date: Oct 2003 Location: Southport Lancashire, UK. Posts: 3,233	Re: Faulty on/off volume pot on a Hacker GP42 As StationX says these can be repaired. I have also had good results with crackly volume controls by cleaning the track then packing it with Vaseline. It is rather counter intuitive but I did it with a mid '30s radio several years ago and it still works perfectly. I got the idea from someone who said they pack it with Waxoyl but I would have thought that the thinner in that would evaporate leaving thick, hard wax. I imagine that the silicone grease recommended for the switch would work as well as Vaseline on the track __________________ Paul

21st Jun 2021, 2:45 pm	#12
PJay1966 Pentode Join Date: May 2021 Location: Buckinghamshire, UK. Posts: 133	Re: Faulty on/off volume pot on a Hacker GP42 Thanks Paul It’s fixed now and seems fine so far!