Vidor CN430 My Lady Anne - Page 4 - UK Vintage Radio Repair and Restoration Discussion Forum

gary_crutchley · 2nd Mar 2016, 10:16 am

Thanks all for your help. My plan from here is to change the V3 screen grid decoupling cap (C18) then see how the set performs for a while whilst I order replacements for R10 and R11. No doubt I will be back shortly with an update.

gary_crutchley · 3rd Mar 2016, 9:49 am

Hi all,

I have a bit of an update on my progress with this set. I checked R11 with a Robin meter that I borrowed (having a father who is a retired spark is great from a tools point of view!), it measured 2.85MΩ (it should be 2.7MΩ) hence like R10 it is high. Therefore the plan is to change R10, R11 and C18.

As I have worked with the set I have noticed that the volume response was somewhat variable. With the volume knob set to maximum it was sometimes loud but on other occasions less so. Also it appeared to affect MW only, but I could be wrong on that point.

I waggled the valves and traced the fault to a connection problem with V3. Then I noticed that the ground connection between the metal valve screen and the volume pot was poor, so I re-soldered both that and the connection on to the valve screen itself. That improved and stabilised the volume, which is now very loud.

I also noticed a connection issue with one of the pins in the valve holder, one which didn’t respond to cleaning. I manipulated the tag a little and it seems to be improved for now.

However, here is the odd thing: The lid closure buzzer was working when the volume was low (i.e: with the connection issues present), but it is now not working with the volume high. If I move the valve so that the connection issue comes back and the volume goes low, the buzzer works again.

Any ideas please?

Regards,

Gary

Phil G4SPZ · 3rd Mar 2016, 9:52 am

Gary,

2.85 Megohms is well within the tolerance for a 2.7 Megohm resistor - leave it alone!

'LIVEWIRE?' · 3rd Mar 2016, 9:55 am

Could the buzzer still be working, but not audible above the music, etc.? You do say the volume is now very loud!

gary_crutchley · 3rd Mar 2016, 10:24 am

Quote:

Originally Posted by Phil G4SPZ

2.85 Megohms is well within the tolerance for a 2.7 Megohm resistor - leave it alone!

Okay will do!

gary_crutchley · 3rd Mar 2016, 10:26 am

Quote:

Originally Posted by 'LIVEWIRE?'

Could the buzzer still be working, but not audible above the music, etc.? You do say the volume is now very loud!

I don't think so as the buzzer is very, very loud when it operates. Also it seems to stop/disconnect the audio.

Boater Sam · 3rd Mar 2016, 10:33 am

The lid closing shuts the radio off by way of turning the output valve into an oscillator by positive feedback. Maybe with the volume high, the pot is reducing the feedback signal on the grid, or it is driving the valve to cut off.
Check the voltage on the cathode of the output valve and make sure it is not too high in that condition, not good for the valve to over dissipate.

Phil G4SPZ · 3rd Mar 2016, 10:35 am

Valveholder pins on battery sets are a common cause of intermittent faults, a particular nuisance in portable sets that get moved around. If you're lucky, with care you may be able to extract the single faulty connection and replace it with one taken from an identical type of sacrificial valveholder, but otherwise you will have to replace the complete valveholder. It's not as difficult as it sounds, just time-consuming. I've had to do it a couple of times.

gary_crutchley · 3rd Mar 2016, 11:34 am

Quote:

Originally Posted by Boater Sam

The lid closing shuts the radio off by way of turning the output valve into an oscillator by positive feedback. Maybe with the volume high, the pot is reducing the feedback signal on the grid, or it is driving the valve to cut off.
Check the voltage on the cathode of the output valve and make sure it is not too high in that condition, not good for the valve to over dissipate.

Thanks Sam, I will do that and report back. Actually I was curious more than anything, I'm not greatly bothered that it doesn't buzz. I don't intend to shut the lid with the power still applied.

gary_crutchley · 3rd Mar 2016, 11:41 am

Quote:

Originally Posted by Phil G4SPZ

Valveholder pins on battery sets are a common cause of intermittent faults, a particular nuisance in portable sets that get moved around. If you're lucky, with care you may be able to extract the single faulty connection and replace it with one taken from an identical type of sacrificial valveholder, but otherwise you will have to replace the complete valveholder. It's not as difficult as it sounds, just time-consuming. I've had to do it a couple of times.

Thanks Phil. I think you mentioned that before when we were talking about cleaning the valve holders. It's working for now so there is no immediate need for a change and if I fiddle with it I probably will break it. I will see how it goes, once I have changed R10 and C18 I plan to run the set for a while to see how it performs before contemplating anything else.

I am currently trying to determine if I can do anything about the yellowed plastic covering on the outside of the case. It's not responding at the moment.

Chindit · 3rd Mar 2016, 12:12 pm

I wonder if a gentle application of T-cut would help? It is probably nicotine based staining and it may well come off with a suitable mild abrasive such as the above.
I've found it will even work on the silver/grey-painted areas of a Philips N4506 tape deck - just a gentle rub and and yellow/ brown deposits just melt away!
Regarding B7G valve holder pins; I've had numerous problems over the years with bad or non-existant contacts in my battery sets and now they are one of the very first things I look at. As mentioned, it is easy just to unsolder any particularly bad or broken pins, straighten them out and push them through from underneath. You need to clean the tags up well though as they are a tight fit. Extract the new ones from an unused valve holder, feed them in and lightly bend them to keep the in place. Resolder and Bob's your Uncle!
Colin.

gary_crutchley · 3rd Mar 2016, 12:40 pm

Hi Colin,

Thanks for the advice. I think I have some T-Cut somewhere, I can try it on the base is the set has the same material covering there and it is rather grubby.

It sounds as though the valve holders can be a bit of an issue.

Regards,

Gary

KeithsTV · 3rd Mar 2016, 12:45 pm

The varying volume could be due to a noisy volume control. A squirt of Servisol should make that better.

In these sets there are often several unused pins on the valveholders, which can be used to replaced the faulty ones. The problem comes if there are more faulty pins than replacements which happened to me last year. Fortunately I had a scrap set with similar pins.

As has been said R11 is well within tolerance. In fact I'm surprised that after all this time it is actually still in tolerance as these high value resistors tend to go high. I'd be more concerned about the decoupling caps as these will almost certainly be leaky and need replacing.

Keith

gary_crutchley · 3rd Mar 2016, 2:16 pm

Thanks very much Keith, that's a great idea. I will look for a spare pin on that holder, I think pin 2 should be free.

I was a little surprised too. When I connected the meter across it the initial reading was below 2.0MΩ, but it rose rapidly, slowing down to almost nothing at 2.85MΩ. I presume the resistor was warming up slightly, and it's resistance was increasing as it did so. I had the meter connected for a few minutes before settling on the final reading.

julie_m · 3rd Mar 2016, 2:21 pm

Is there a capacitor shunting it? That would explain it starting at short and increasing, as the capacitor charged.

gary_crutchley · 3rd Mar 2016, 2:40 pm

Yes I think so. It's R11 in the diagram, which I think is shunted by C18.

Thanks Julie.

KeithsTV · 3rd Mar 2016, 7:33 pm

It will be the main electrolytics shunting R11 with a leakage path through C18 suggesting that C18 needs to be changed.

Keith

gary_crutchley · 3rd Mar 2016, 11:20 pm

Thanks for that Keith, we plan to change C18 in any case. Many thanks for your help.

I've had a go at cleaning the case this evening, it cleaned up well although the yellowing of the white/cream covering hasn't gone away. Nothing would touch it, detergent, T-Cut, bleach nor white spirit. I don't think it's nicotine/tar, it must be ageing of the plastic material.

Gary

Chindit · 4th Mar 2016, 9:37 am

Hello, I've just twigged what you meant by yellowing plastic covering. I was thinking you meant the moulded plastic parts that form the speaker grill, but of course you mean the cloth-like covering on the wooden case.
In this case, may I revise my advise slightly. Start with aerosol car upholstery cleaning foam and scrub it in a circular motion with a stiff tooth brush or nail brush. Then wipe away the residual foam and lifted muck with a damp floor cloth or similar. Pat dry with a towel and then leave to dry throughly. Any areas along the seams that are lifting can be glued back with evostik or similar.
Hope this helps and sorry for the confusion.
Colin.

vidjoman · 4th Mar 2016, 9:45 am

I have a Lady Anne and part of the covering is a deep cream which looks like it's nicotine stained. As it came form an aunt that never allowed anyone to smoke in her house and kept the radio covered when not in use I can say it's the original colour. They probably did other colour combinations though.

2nd Mar 2016, 10:16 am	#61
gary_crutchley Heptode Join Date: Apr 2013 Location: Bloxwich, West Midlands, UK Posts: 554	Re: Vidor CN430 My Lady Anne Thanks all for your help. My plan from here is to change the V3 screen grid decoupling cap (C18) then see how the set performs for a while whilst I order replacements for R10 and R11. No doubt I will be back shortly with an update. __________________ http://www.crutchleyhistory.co.uk/

3rd Mar 2016, 9:49 am	#62
gary_crutchley Heptode Join Date: Apr 2013 Location: Bloxwich, West Midlands, UK Posts: 554	Re: Vidor CN430 My Lady Anne Hi all, I have a bit of an update on my progress with this set. I checked R11 with a Robin meter that I borrowed (having a father who is a retired spark is great from a tools point of view!), it measured 2.85MΩ (it should be 2.7MΩ) hence like R10 it is high. Therefore the plan is to change R10, R11 and C18. As I have worked with the set I have noticed that the volume response was somewhat variable. With the volume knob set to maximum it was sometimes loud but on other occasions less so. Also it appeared to affect MW only, but I could be wrong on that point. I waggled the valves and traced the fault to a connection problem with V3. Then I noticed that the ground connection between the metal valve screen and the volume pot was poor, so I re-soldered both that and the connection on to the valve screen itself. That improved and stabilised the volume, which is now very loud. I also noticed a connection issue with one of the pins in the valve holder, one which didn’t respond to cleaning. I manipulated the tag a little and it seems to be improved for now. However, here is the odd thing: The lid closure buzzer was working when the volume was low (i.e: with the connection issues present), but it is now not working with the volume high. If I move the valve so that the connection issue comes back and the volume goes low, the buzzer works again. Any ideas please? Regards, Gary __________________ http://www.crutchleyhistory.co.uk/ Last edited by gary_crutchley; 3rd Mar 2016 at 9:51 am. Reason: Typo

3rd Mar 2016, 9:52 am	#63
Phil G4SPZ Dekatron Join Date: Apr 2005 Location: Bewdley, Worcestershire, UK. Posts: 4,748	Re: Vidor CN430 My Lady Anne Gary, 2.85 Megohms is well within the tolerance for a 2.7 Megohm resistor - leave it alone! __________________ Phil Optimist [n]: One who is not in possession of the full facts

3rd Mar 2016, 9:55 am	#64
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: Vidor CN430 My Lady Anne Could the buzzer still be working, but not audible above the music, etc.? You do say the volume is now very loud!

3rd Mar 2016, 10:33 am	#67
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Vidor CN430 My Lady Anne The lid closing shuts the radio off by way of turning the output valve into an oscillator by positive feedback. Maybe with the volume high, the pot is reducing the feedback signal on the grid, or it is driving the valve to cut off. Check the voltage on the cathode of the output valve and make sure it is not too high in that condition, not good for the valve to over dissipate.

3rd Mar 2016, 10:35 am	#68
Phil G4SPZ Dekatron Join Date: Apr 2005 Location: Bewdley, Worcestershire, UK. Posts: 4,748	Re: Vidor CN430 My Lady Anne Valveholder pins on battery sets are a common cause of intermittent faults, a particular nuisance in portable sets that get moved around. If you're lucky, with care you may be able to extract the single faulty connection and replace it with one taken from an identical type of sacrificial valveholder, but otherwise you will have to replace the complete valveholder. It's not as difficult as it sounds, just time-consuming. I've had to do it a couple of times. __________________ Phil Optimist [n]: One who is not in possession of the full facts Last edited by Phil G4SPZ; 3rd Mar 2016 at 10:36 am. Reason: Spelling

3rd Mar 2016, 12:12 pm	#71
Chindit Tetrode Join Date: Feb 2011 Location: Bishop Auckland, County Durham, UK. Posts: 97	Re: Vidor CN430 My Lady Anne I wonder if a gentle application of T-cut would help? It is probably nicotine based staining and it may well come off with a suitable mild abrasive such as the above. I've found it will even work on the silver/grey-painted areas of a Philips N4506 tape deck - just a gentle rub and and yellow/ brown deposits just melt away! Regarding B7G valve holder pins; I've had numerous problems over the years with bad or non-existant contacts in my battery sets and now they are one of the very first things I look at. As mentioned, it is easy just to unsolder any particularly bad or broken pins, straighten them out and push them through from underneath. You need to clean the tags up well though as they are a tight fit. Extract the new ones from an unused valve holder, feed them in and lightly bend them to keep the in place. Resolder and Bob's your Uncle! Colin.

3rd Mar 2016, 12:40 pm	#72
gary_crutchley Heptode Join Date: Apr 2013 Location: Bloxwich, West Midlands, UK Posts: 554	Re: Vidor CN430 My Lady Anne Hi Colin, Thanks for the advice. I think I have some T-Cut somewhere, I can try it on the base is the set has the same material covering there and it is rather grubby. It sounds as though the valve holders can be a bit of an issue. Regards, Gary __________________ http://www.crutchleyhistory.co.uk/

3rd Mar 2016, 12:45 pm	#73
KeithsTV Nonode Join Date: Aug 2007 Location: South Bradford, West Yorkshire, UK. Posts: 2,573	Re: Vidor CN430 My Lady Anne The varying volume could be due to a noisy volume control. A squirt of Servisol should make that better. In these sets there are often several unused pins on the valveholders, which can be used to replaced the faulty ones. The problem comes if there are more faulty pins than replacements which happened to me last year. Fortunately I had a scrap set with similar pins. As has been said R11 is well within tolerance. In fact I'm surprised that after all this time it is actually still in tolerance as these high value resistors tend to go high. I'd be more concerned about the decoupling caps as these will almost certainly be leaky and need replacing. Keith

3rd Mar 2016, 2:16 pm	#74
gary_crutchley Heptode Join Date: Apr 2013 Location: Bloxwich, West Midlands, UK Posts: 554	Re: Vidor CN430 My Lady Anne Thanks very much Keith, that's a great idea. I will look for a spare pin on that holder, I think pin 2 should be free. I was a little surprised too. When I connected the meter across it the initial reading was below 2.0MΩ, but it rose rapidly, slowing down to almost nothing at 2.85MΩ. I presume the resistor was warming up slightly, and it's resistance was increasing as it did so. I had the meter connected for a few minutes before settling on the final reading. __________________ http://www.crutchleyhistory.co.uk/

3rd Mar 2016, 2:21 pm	#75
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Vidor CN430 My Lady Anne Is there a capacitor shunting it? That would explain it starting at short and increasing, as the capacitor charged. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

3rd Mar 2016, 2:40 pm	#76
gary_crutchley Heptode Join Date: Apr 2013 Location: Bloxwich, West Midlands, UK Posts: 554	Re: Vidor CN430 My Lady Anne Yes I think so. It's R11 in the diagram, which I think is shunted by C18. Thanks Julie. __________________ http://www.crutchleyhistory.co.uk/

3rd Mar 2016, 7:33 pm	#77
KeithsTV Nonode Join Date: Aug 2007 Location: South Bradford, West Yorkshire, UK. Posts: 2,573	Re: Vidor CN430 My Lady Anne It will be the main electrolytics shunting R11 with a leakage path through C18 suggesting that C18 needs to be changed. Keith

3rd Mar 2016, 11:20 pm	#78
gary_crutchley Heptode Join Date: Apr 2013 Location: Bloxwich, West Midlands, UK Posts: 554	Re: Vidor CN430 My Lady Anne Thanks for that Keith, we plan to change C18 in any case. Many thanks for your help. I've had a go at cleaning the case this evening, it cleaned up well although the yellowing of the white/cream covering hasn't gone away. Nothing would touch it, detergent, T-Cut, bleach nor white spirit. I don't think it's nicotine/tar, it must be ageing of the plastic material. Gary __________________ http://www.crutchleyhistory.co.uk/ Last edited by gary_crutchley; 3rd Mar 2016 at 11:23 pm. Reason: Information added

4th Mar 2016, 9:37 am	#79
Chindit Tetrode Join Date: Feb 2011 Location: Bishop Auckland, County Durham, UK. Posts: 97	Re: Vidor CN430 My Lady Anne Hello, I've just twigged what you meant by yellowing plastic covering. I was thinking you meant the moulded plastic parts that form the speaker grill, but of course you mean the cloth-like covering on the wooden case. In this case, may I revise my advise slightly. Start with aerosol car upholstery cleaning foam and scrub it in a circular motion with a stiff tooth brush or nail brush. Then wipe away the residual foam and lifted muck with a damp floor cloth or similar. Pat dry with a towel and then leave to dry throughly. Any areas along the seams that are lifting can be glued back with evostik or similar. Hope this helps and sorry for the confusion. Colin.

4th Mar 2016, 9:45 am	#80
vidjoman Dekatron Join Date: Jun 2013 Location: East Sussex, UK. Posts: 3,323	Re: Vidor CN430 My Lady Anne I have a Lady Anne and part of the covering is a deep cream which looks like it's nicotine stained. As it came form an aunt that never allowed anyone to smoke in her house and kept the radio covered when not in use I can say it's the original colour. They probably did other colour combinations though.