Vidor Gem. - UK Vintage Radio Repair and Restoration Discussion Forum

pepmin 1 · 12th Apr 2018, 5:55 pm

I recently bought this as a non working radio. Purely for nostalgic reasons as I had an old one as a kid and had been on the look out for another one for a long time. When I connect a battery all I get is what I think is termed as motorboating but not all off the time. In between that I get low level whistling and a clicking sound but there is plenty off loud hiss. Radio 4 is preset on this radio and for a second or two when switching on that comes through loud and clear then fades to a whistle and disappears. I was having a look at the radio today and for no apparent reason radio 4 stayed on loud and clear for an hour and more but when I switched it off and back on it reverted back to working for a sec or two when first switched on. While it was going I tried medium wave but was getting lots off whistling, I was still able to tune into stations loud and clear. I hoped it would be a capacitor issue so I piggy backed all off the electrolytics with new ones but this made no difference. The radio is full off hunts capacitors but I manually piggy backed those as well with no results. I cleaned the MW/LW switch and checked for any loose connections and bad solder joints. That is about the extent of my knowledge with transistor radios. Any tips about what I might be able to do to get this radio going would be appreciated but I have to say that if you use electronic speak my eyes will glaze over, although I understand that may help others reading this post. I have downloaded the service data from this site so I could get capacitors values. As for the rest of it I may as well be reading Egyptian hieroglyphics At the end off the day if I cant fix it I will just clean up the cabinet and use it as a display item. Colin

Robert Darwent · 12th Apr 2018, 6:20 pm

Hi Colin,

Short answer - replace all the Hunts and electrolytics, especially the type with a yellow label and a red and black end!

Bridging or piggy backing each capacitor in turn as you have done is fine if only one capacitor is causing the issue. In this case all of the the previously mentioned above are suspect in a radio of this age and the instability or motor-boating is most likely due to several of the capacitors. For peace of mind and reliable future operation - change them all

Regards

pepmin 1 · 12th Apr 2018, 6:31 pm

Hi Robert. Thanks for that. I should have said I did think of that. Today I soldered all off the electrolytic s to the board and that made no difference. I did not do that to the non electrolytic s though.

Robert Darwent · 12th Apr 2018, 7:15 pm

Change the electrolytics first and see if that cures the instability - if you're lucky you might avoid having to change the Hunts. Hunts used in a transistor set lead a less stressful life than in a mains valve set and are often still OK - I always change those yellow label electrolytics on sight though!

Regards

pepmin 1 · 12th Apr 2018, 8:41 pm

I was having another go at it. I switched it on and off but same thing. I must have forgot to switch it off and after 15mins it suddenly burst into life and still going? but only on long wave this time. I am struggling with capacitors. I took a list to Maplins who have very little stock left.I got a few of those horrible little ceramic jobs but not all that I needed and only near to the values I asked for. I already had some electrolytics. What value could I substitute for 0.04? there are a few off them. Also what is a suflex capacitor? are they non electrolytic?

'LIVEWIRE?' · 12th Apr 2018, 10:13 pm

0.047uf is the nearest available modern value to 0.04uf. For many years now, xcapacitors & resistors have beeb made in what are termed preferred values, commonly 1, 2.2, 3.3, 4.7, 6.8, 8.2, 9.1 and their multiples. This applies to capacitors, resistors and inductors. The working voltage of replacement capacitors should be equal to, or greater than, that of the originals. A Suflex capacitor is not electrolytic, but a (non-polarized) polystyrene component.

crackle · 12th Apr 2018, 10:43 pm

You do not always need to change the paper hunts caps, they have an easy life in a transistor radio and leakage at these low voltages is very low and almost negligible.
These are a fairly uncommon radio, and sometimes it is nicer to keep the radio as original as possible, it certainly is if you want it to keep its value.
It may be if you power it on, check the current is not overly high, and leave it running for some time, if the current is not too much over spec. then things may start to work better.
I had one of these and it worked first time, even with the red and black plessey caps.
It may come to working your way around the circuit board gently wiggling or tapping each component to see if there is a dry solder joint.

Mike

marconi_pete · 12th Apr 2018, 10:53 pm

If you're still experiencing instability and your set has those Suflex capacitors, then they could be causing your problem. Its not unheard of for those suffix caps to cause instability. For buying new caps check out cricklewood electronics. (I'm not affiliated with them, just a happy customer.) they have a website so you can order online and they charge reasonable prices.

Thanks,
Peter

pepmin 1 · 12th Apr 2018, 11:14 pm

Thanks for that guys. I dont want to replace components that dont need changing because i would rather keep it in original condition. I realise something probably needs changed though. The radio was left switched on earlier tonight and after about 15mins it burst into life and Im sure would still be going yet if i never switched it off. I switched it back on again and it worked for about a second. I left it on for a while but it didnt burst into life this time but it did when I switched it off and back on. Its been going for two hours now!!

What is a replacment for those sufix capacitors?

marconi_pete · 12th Apr 2018, 11:21 pm

For replacing those suflex caps, I just use the yellow polyester axial caps rated at 630vdc. They are also suitable for replacing the black and brown Hunts mouldseal caps too. Just a thought. Have you cleaned the on/off/volume pot and the wave change switch with switch cleaner? It may be that the set has dirty contacts, hence why it may be bursting into life when switched off and on again. I'd still go ahead and change the suffix caps though.

Thanks,
Peter

pepmin 1 · 12th Apr 2018, 11:51 pm

Hi Peter. I have cleaned the volume pot and MW/LW switch. there is a small 0.47capacitor that looks like a sufix but when I place a capacitor on it cuts the radio out?

marconi_pete · 13th Apr 2018, 12:03 am

When you say you've "placed a capacitor on it", what do you mean? If you've connected another cap over the existing one while it's still in circuit then this is most likely why. You would need to disconnect the original cap and then solder in the replacement. Make sure the replacement cap is of the same or similar rating as the original.

Thanks,
Peter

pepmin 1 · 13th Apr 2018, 12:34 am

Hi Peter. I have fixed it. Turned out to be a hunts capacitor C10 0.46uf on the circuit. All problems solved and the radio is working fine on MW/LW. Thanks to everyone for their advice. Just need to clean up the cabinet now. Colin

marconi_pete · 13th Apr 2018, 1:59 am

Glad you got it sorted Colin. Enjoy.

Thanks,
Peter

crackle · 13th Apr 2018, 6:34 am

Well done for finding the fault, I know these intermittent ones can be the most difficult.
It would be good to know what was wrong with the Hunts capacitor, was it a dry joint, intermittent internal near short?

Mike

pepmin 1 · 13th Apr 2018, 12:23 pm

Hi Mike. My way off finding the fault was not very scientific I am afraid. I enlarged a picture off the printed circuit on my laptop and just very lightly tacked the appropriate capacitor into the correct position following the circuit ( piggy backed ). I did not do this in any particular order and it was sods law that it was the last capacitor that I tried that fixed the radio. I then removed each capacitor one at a time switching the radio on and off each time to make sure that it was still working.It was time consuming but I dont have the equipment or the skills to properly do fault finding so in this case the ends justify the means. In answer to your question it appears that the capacitor was at fault as I did re solder the connections but the fault was still there. Maybe I should remove all off the hunts capacitors but I dont want to replace them all with horrible modern new ones. The radio is working fine at the moment and It wont be used every day. I will upload a pic as soon as I clean the cabinet and put the radio back together. Colin

pepmin 1 · 13th Apr 2018, 4:45 pm

Finished article. Two off the plastic chassis mountings had broken off but I managed to attach them with epoxy. Gave it a polish and put it together again. looks better in the pics but its not too bad over all. Radio is performing well with plenty off clear and loud audio. Medium wave still gives a bit of a whistle while tuning into a station but nothing that I am going to worry about. long wave is fine. Colin

pepmin 1 · 21st Apr 2018, 2:59 pm

Okay that did not last long.

The radio now only works well on LW. Still works on MW but you need to be fine tuning through the whistling pulsing and chirping as you get near to a station then it is fine. I had it going for 8 hours playing Radio 5 yesterday with no problems at all. The original problem was it would only stay on for a second when switched on then revert to hiss but that is okay now. When I say not staying on I mean you can only hear the station for a sec. As I have said in my previous posts I had piggy backed all off the capacitors and thought that I had found the fault and although I seemed to have fixed the fault off the radio not staying on it is still not a usable radio unless I want to listen to LW all off the time. C10 0.04 seemed to be the culprit but now I am not so sure. While looking at it again I unsoldered the new capacitor and sure enough the original fault occurred again with the radio only staying tuned in for a second. I had left the original hunts capacitor in place. I know that that is probably a no no but the problem seemed to have been fixed, This time I disconnected one side of it and re attached the new capacitor and the radio did not work at all ? I tried this a couple off times and even tried a different capacitor.It would only work if the old capacitor was in circuit with the new one? But still I have all off the whistling etc on MW. Now I know that piggy backing capacitors onto old ones while they are still in circuit is not the proper way to fault find but that is the extent off my skills and it has worked for me on other transistor radios. I think that I should be removing all off the capacitors and replacing them but I am not going to do that. I would rather keep it in as near original condition as possible and maybe some day get someone who can narrow the fault down without needlessly removing components that don't need to be removed. Also the fact that it is not a very common radio means that I should treat it with a bit off respect. Colin

ms660 · 21st Apr 2018, 4:18 pm

Is the battery voltage ok under load...6 volts or there about?

Lawrence.

pepmin 1 · 21st Apr 2018, 10:39 pm

Hi Lawrence. How do I go about checking that ?

12th Apr 2018, 5:55 pm	#1
pepmin 1 Pentode Join Date: Nov 2010 Location: Inverness, Scottish Highlands, UK. Posts: 226	Vidor Gem. I recently bought this as a non working radio. Purely for nostalgic reasons as I had an old one as a kid and had been on the look out for another one for a long time. When I connect a battery all I get is what I think is termed as motorboating but not all off the time. In between that I get low level whistling and a clicking sound but there is plenty off loud hiss. Radio 4 is preset on this radio and for a second or two when switching on that comes through loud and clear then fades to a whistle and disappears. I was having a look at the radio today and for no apparent reason radio 4 stayed on loud and clear for an hour and more but when I switched it off and back on it reverted back to working for a sec or two when first switched on. While it was going I tried medium wave but was getting lots off whistling, I was still able to tune into stations loud and clear. I hoped it would be a capacitor issue so I piggy backed all off the electrolytics with new ones but this made no difference. The radio is full off hunts capacitors but I manually piggy backed those as well with no results. I cleaned the MW/LW switch and checked for any loose connections and bad solder joints. That is about the extent of my knowledge with transistor radios. Any tips about what I might be able to do to get this radio going would be appreciated but I have to say that if you use electronic speak my eyes will glaze over, although I understand that may help others reading this post. I have downloaded the service data from this site so I could get capacitors values. As for the rest of it I may as well be reading Egyptian hieroglyphics At the end off the day if I cant fix it I will just clean up the cabinet and use it as a display item. Colin Attached Thumbnails Last edited by pepmin 1; 12th Apr 2018 at 6:06 pm.

12th Apr 2018, 6:20 pm	#2
Robert Darwent Heptode Join Date: Aug 2006 Location: Sheffield, South Yorkshire, UK Posts: 990	Re: Vidor gem Hi Colin, Short answer - replace all the Hunts and electrolytics, especially the type with a yellow label and a red and black end! Bridging or piggy backing each capacitor in turn as you have done is fine if only one capacitor is causing the issue. In this case all of the the previously mentioned above are suspect in a radio of this age and the instability or motor-boating is most likely due to several of the capacitors. For peace of mind and reliable future operation - change them all Regards __________________ Robert G0UHF www.wavesintheair.co.uk

12th Apr 2018, 6:31 pm	#3
pepmin 1 Pentode Join Date: Nov 2010 Location: Inverness, Scottish Highlands, UK. Posts: 226	Re: Vidor gem Hi Robert. Thanks for that. I should have said I did think of that. Today I soldered all off the electrolytic s to the board and that made no difference. I did not do that to the non electrolytic s though.

12th Apr 2018, 7:15 pm	#4
Robert Darwent Heptode Join Date: Aug 2006 Location: Sheffield, South Yorkshire, UK Posts: 990	Re: Vidor gem Change the electrolytics first and see if that cures the instability - if you're lucky you might avoid having to change the Hunts. Hunts used in a transistor set lead a less stressful life than in a mains valve set and are often still OK - I always change those yellow label electrolytics on sight though! Regards __________________ Robert G0UHF www.wavesintheair.co.uk

12th Apr 2018, 8:41 pm	#5
pepmin 1 Pentode Join Date: Nov 2010 Location: Inverness, Scottish Highlands, UK. Posts: 226	Re: Vidor gem I was having another go at it. I switched it on and off but same thing. I must have forgot to switch it off and after 15mins it suddenly burst into life and still going? but only on long wave this time. I am struggling with capacitors. I took a list to Maplins who have very little stock left.I got a few of those horrible little ceramic jobs but not all that I needed and only near to the values I asked for. I already had some electrolytics. What value could I substitute for 0.04? there are a few off them. Also what is a suflex capacitor? are they non electrolytic? Last edited by pepmin 1; 12th Apr 2018 at 9:11 pm.

12th Apr 2018, 10:13 pm	#6
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: Vidor gem 0.047uf is the nearest available modern value to 0.04uf. For many years now, xcapacitors & resistors have beeb made in what are termed preferred values, commonly 1, 2.2, 3.3, 4.7, 6.8, 8.2, 9.1 and their multiples. This applies to capacitors, resistors and inductors. The working voltage of replacement capacitors should be equal to, or greater than, that of the originals. A Suflex capacitor is not electrolytic, but a (non-polarized) polystyrene component.

12th Apr 2018, 10:43 pm	#7
crackle Rest in Peace Join Date: Mar 2011 Location: Basildon, Essex, UK. Posts: 4,100	Re: Vidor gem You do not always need to change the paper hunts caps, they have an easy life in a transistor radio and leakage at these low voltages is very low and almost negligible. These are a fairly uncommon radio, and sometimes it is nicer to keep the radio as original as possible, it certainly is if you want it to keep its value. It may be if you power it on, check the current is not overly high, and leave it running for some time, if the current is not too much over spec. then things may start to work better. I had one of these and it worked first time, even with the red and black plessey caps. It may come to working your way around the circuit board gently wiggling or tapping each component to see if there is a dry solder joint. Mike

12th Apr 2018, 10:53 pm	#8
marconi_pete Hexode Join Date: Mar 2012 Location: London, UK. Posts: 347	Re: Vidor gem If you're still experiencing instability and your set has those Suflex capacitors, then they could be causing your problem. Its not unheard of for those suffix caps to cause instability. For buying new caps check out cricklewood electronics. (I'm not affiliated with them, just a happy customer.) they have a website so you can order online and they charge reasonable prices. Thanks, Peter

12th Apr 2018, 11:14 pm	#9
pepmin 1 Pentode Join Date: Nov 2010 Location: Inverness, Scottish Highlands, UK. Posts: 226	Re: Vidor gem Thanks for that guys. I dont want to replace components that dont need changing because i would rather keep it in original condition. I realise something probably needs changed though. The radio was left switched on earlier tonight and after about 15mins it burst into life and Im sure would still be going yet if i never switched it off. I switched it back on again and it worked for about a second. I left it on for a while but it didnt burst into life this time but it did when I switched it off and back on. Its been going for two hours now!! What is a replacment for those sufix capacitors?

12th Apr 2018, 11:21 pm	#10
marconi_pete Hexode Join Date: Mar 2012 Location: London, UK. Posts: 347	Re: Vidor gem For replacing those suflex caps, I just use the yellow polyester axial caps rated at 630vdc. They are also suitable for replacing the black and brown Hunts mouldseal caps too. Just a thought. Have you cleaned the on/off/volume pot and the wave change switch with switch cleaner? It may be that the set has dirty contacts, hence why it may be bursting into life when switched off and on again. I'd still go ahead and change the suffix caps though. Thanks, Peter Last edited by marconi_pete; 12th Apr 2018 at 11:30 pm.

12th Apr 2018, 11:51 pm	#11
pepmin 1 Pentode Join Date: Nov 2010 Location: Inverness, Scottish Highlands, UK. Posts: 226	Re: Vidor gem Hi Peter. I have cleaned the volume pot and MW/LW switch. there is a small 0.47capacitor that looks like a sufix but when I place a capacitor on it cuts the radio out?

13th Apr 2018, 12:03 am	#12
marconi_pete Hexode Join Date: Mar 2012 Location: London, UK. Posts: 347	Re: Vidor gem When you say you've "placed a capacitor on it", what do you mean? If you've connected another cap over the existing one while it's still in circuit then this is most likely why. You would need to disconnect the original cap and then solder in the replacement. Make sure the replacement cap is of the same or similar rating as the original. Thanks, Peter

13th Apr 2018, 12:34 am	#13
pepmin 1 Pentode Join Date: Nov 2010 Location: Inverness, Scottish Highlands, UK. Posts: 226	Re: Vidor gem Hi Peter. I have fixed it. Turned out to be a hunts capacitor C10 0.46uf on the circuit. All problems solved and the radio is working fine on MW/LW. Thanks to everyone for their advice. Just need to clean up the cabinet now. Colin

13th Apr 2018, 1:59 am	#14
marconi_pete Hexode Join Date: Mar 2012 Location: London, UK. Posts: 347	Re: Vidor gem Glad you got it sorted Colin. Enjoy. Thanks, Peter

13th Apr 2018, 6:34 am	#15
crackle Rest in Peace Join Date: Mar 2011 Location: Basildon, Essex, UK. Posts: 4,100	Re: Vidor gem Well done for finding the fault, I know these intermittent ones can be the most difficult. It would be good to know what was wrong with the Hunts capacitor, was it a dry joint, intermittent internal near short? Mike

13th Apr 2018, 12:23 pm	#16
pepmin 1 Pentode Join Date: Nov 2010 Location: Inverness, Scottish Highlands, UK. Posts: 226	Re: Vidor gem Hi Mike. My way off finding the fault was not very scientific I am afraid. I enlarged a picture off the printed circuit on my laptop and just very lightly tacked the appropriate capacitor into the correct position following the circuit ( piggy backed ). I did not do this in any particular order and it was sods law that it was the last capacitor that I tried that fixed the radio. I then removed each capacitor one at a time switching the radio on and off each time to make sure that it was still working.It was time consuming but I dont have the equipment or the skills to properly do fault finding so in this case the ends justify the means. In answer to your question it appears that the capacitor was at fault as I did re solder the connections but the fault was still there. Maybe I should remove all off the hunts capacitors but I dont want to replace them all with horrible modern new ones. The radio is working fine at the moment and It wont be used every day. I will upload a pic as soon as I clean the cabinet and put the radio back together. Colin

13th Apr 2018, 4:45 pm	#17
pepmin 1 Pentode Join Date: Nov 2010 Location: Inverness, Scottish Highlands, UK. Posts: 226	Re: Vidor Gem. Finished article. Two off the plastic chassis mountings had broken off but I managed to attach them with epoxy. Gave it a polish and put it together again. looks better in the pics but its not too bad over all. Radio is performing well with plenty off clear and loud audio. Medium wave still gives a bit of a whistle while tuning into a station but nothing that I am going to worry about. long wave is fine. Colin Attached Thumbnails

21st Apr 2018, 2:59 pm	#18
pepmin 1 Pentode Join Date: Nov 2010 Location: Inverness, Scottish Highlands, UK. Posts: 226	Re: Vidor Gem. Okay that did not last long. The radio now only works well on LW. Still works on MW but you need to be fine tuning through the whistling pulsing and chirping as you get near to a station then it is fine. I had it going for 8 hours playing Radio 5 yesterday with no problems at all. The original problem was it would only stay on for a second when switched on then revert to hiss but that is okay now. When I say not staying on I mean you can only hear the station for a sec. As I have said in my previous posts I had piggy backed all off the capacitors and thought that I had found the fault and although I seemed to have fixed the fault off the radio not staying on it is still not a usable radio unless I want to listen to LW all off the time. C10 0.04 seemed to be the culprit but now I am not so sure. While looking at it again I unsoldered the new capacitor and sure enough the original fault occurred again with the radio only staying tuned in for a second. I had left the original hunts capacitor in place. I know that that is probably a no no but the problem seemed to have been fixed, This time I disconnected one side of it and re attached the new capacitor and the radio did not work at all ? I tried this a couple off times and even tried a different capacitor.It would only work if the old capacitor was in circuit with the new one? But still I have all off the whistling etc on MW. Now I know that piggy backing capacitors onto old ones while they are still in circuit is not the proper way to fault find but that is the extent off my skills and it has worked for me on other transistor radios. I think that I should be removing all off the capacitors and replacing them but I am not going to do that. I would rather keep it in as near original condition as possible and maybe some day get someone who can narrow the fault down without needlessly removing components that don't need to be removed. Also the fact that it is not a very common radio means that I should treat it with a bit off respect. Colin Attached Thumbnails Last edited by pepmin 1; 21st Apr 2018 at 3:19 pm.

21st Apr 2018, 4:18 pm	#19
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Vidor Gem. Is the battery voltage ok under load...6 volts or there about? Lawrence.

21st Apr 2018, 10:39 pm	#20
pepmin 1 Pentode Join Date: Nov 2010 Location: Inverness, Scottish Highlands, UK. Posts: 226	Re: Vidor Gem. Hi Lawrence. How do I go about checking that ?