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Old 27th Mar 2016, 5:47 pm   #101
ms660
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Default Re: Vidor CN430 My Lady Anne

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Originally Posted by gary_crutchley View Post
The valve holder is riveted to the chassis, how can these be removed please?
Looking at previous pics posted the rivets look like hollow rivets, if so then drill the rivets out from the top side, a sharp drill that's slightly oversized to the fixing hole is what's needed, possibly a 4mm drill ? The top of the rivet should part as a ring, the rest can then be pushed/wiggled out.

Use pop rivets or BA screws/nuts to fit replacement valve socket, whichever suits.

Lawrence. EDIT: Whoops... Post crossed with Phil's.
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Old 27th Mar 2016, 6:02 pm   #102
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Default Re: Vidor CN430 My Lady Anne

Great minds think alike, Lawrence!
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Old 27th Mar 2016, 6:09 pm   #103
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Default Re: Vidor CN430 My Lady Anne

Yes, done a few on radios and Landrovers over the years.

Lawrence.
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Old 27th Mar 2016, 8:38 pm   #104
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Default Re: Vidor CN430 My Lady Anne

Thanks all. I will let you know how we get on.
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Old 28th Mar 2016, 10:32 pm   #105
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Default Re: Vidor CN430 My Lady Anne

Hi all,

This might be worth posting. In post #62 I noted that the lid closure buzzer was working when the volume was low but it is now not working with the volume high. Oddly it is now working the other way around (i.e: the buzzer operates when the volume is high) and is consistent, no matter what I do.

Regards,

Gary
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Old 29th Mar 2016, 6:44 am   #106
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Default Re: Vidor CN430 My Lady Anne

Hi Gary
you don't need to replace the valve holder
the contacts can be replaced individually.
I can put some in the post for you.
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Old 29th Mar 2016, 8:57 am   #107
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Default Re: Vidor CN430 My Lady Anne

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...the lid closure buzzer was working when the volume was low but it is now not working with the volume high. Oddly it is now working the other way around (i.e: the buzzer operates when the volume is high)...
Gary, I think that the syndrome you are seeing may be linked with the duff valveholder on V3. If you look at Trader service sheet 1215 you will see that S6 (the lid switch) closes and connects C19 between the anode of V4 and the screen grid of V3. This provides positive feedback between the two valves, the amplitude of which will depend to an extent on the gain of V3 which in turn depends on its screen grid voltage. It sounds very much like you have a poor connection between V3's screen grid pin and the corresponding socket in the valveholder. This is, of course, impossible to check by measuring the voltage at the valveholder tag, making this a tricky fault... you can guess how long it took me to find my first example of this type of fault.

You can either try replacing the single pin or the entire valveholder. I have done both types of repair. The 'single pin' approach has the benefit of speed and relative simplicity, but of course you need to know which pin is faulty, have an identical type of pin available as a replacement - they do vary - and it will not solve problems caused by other defective pins in the same valveholder. You may find that you still get intermittent contact once you've replaced a single pin.

The choice is yours.

Phil
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Last edited by Phil G4SPZ; 29th Mar 2016 at 8:59 am. Reason: Afterthought
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Old 29th Mar 2016, 9:12 am   #108
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Default Re: Vidor CN430 My Lady Anne

Change the valve socket, job done, the exercise will be good for practical skills.

Lawrence.
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Old 29th Mar 2016, 10:18 pm   #109
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Default Re: Vidor CN430 My Lady Anne

If the valve holder has those little fork contacts, then they can be replaced individually. You can tell if the contact is broken by moving them gently with a needle. I find this easier than changing the whole valve holder and less prone to wiring errors.
Mike
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Old 30th Mar 2016, 9:49 am   #110
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Default Re: Vidor CN430 My Lady Anne

Vidor seemed to stick with McMurdo valveholders. The pins if these can indeed be replaced individually, which is less work, more originality, better all round!

Battery sets seem to need this done. It's not a fault with the valveholders as such, but fumes from the batteries corroding the valveholder pins. Other equipment using these valveholders shows no problem.

Just remove all the wires from a pin, suck off the solder, straighten it with a pair of pliers, and remove.

I can supply a donor valveholder or two if you need - PM me.
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Old 30th Mar 2016, 10:05 am   #111
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Default Re: Vidor CN430 My Lady Anne

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Other equipment using these valveholders shows no problem...
I'm not so sure. I once had to replace a B7G valveholder in a mains-powered KB FB10 due to a cracked pin - I didn't have a matching pin as a replacement.

I feel a bit sorry for Gary, as he is being bombarded with conflicting advice! Perhaps he should try replacing the one pin first, taking advantage of the kind offers of parts, then if not successful resort to replacing the whole valveholder. There are pros and cons to both approaches, and neither is always right all of the time.
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Old 30th Mar 2016, 10:44 am   #112
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Arrow Re: Vidor CN430 My Lady Anne

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Originally Posted by kalee20 View Post
Battery sets seem to need this done. It's not a fault with the valve holders as such, but fumes from the batteries corroding the valve holder pins. Other equipment using these valve holders shows no problem.
Which has not been my experience. The Eddystone 680X uses those: once I had to replace seven valve sockets of that type. I have met the split-pin type of valve socket in other Eddystone radios and some items of test equipment. If in any doubt, I always replace those with the common 'wrap-around' type to increase reliability. Replacing valve sockets is rarely a straight-forward task: I only want to do it once. Hence, I always replace split-pin types with a quality valve socket.

Al/
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Old 30th Mar 2016, 12:50 pm   #113
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Default Re: Vidor CN430 My Lady Anne

Interesting! I can't argue with other folks' experiences.

I'd still say, if it's just ONE pin that seems duff, replace that pin as it's well over seven times more work to replace the whole valve holder.
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Old 30th Mar 2016, 1:51 pm   #114
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Default Re: Vidor CN430 My Lady Anne

Perhaps battery sets were more likely to be used and/or finally stored in shed/garage/loft over extended periods etc. than a bigger, heavier mains set, and thus more exposed to humidity than a bulky, outlet-tied set. Maybe the thorough warming over several hours of regular use in mains sets also contributes to their seemingly faring better than in a battery set. Interesting angle on battery fumes, though- most of us will be familiar with accelerated corrosion in the vicinity of a car battery, though it has to be admitted that these are pretty anti-social devices with their aura of acid fumes. Wouldn't be surprised if there was some amount of corrosive vapour associated with basic construction cells in cardboard cartons.
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Old 30th Mar 2016, 2:31 pm   #115
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Default Re: Vidor CN430 My Lady Anne

There definitely is - and quite a lot of battery sets show signs of leakage.

It did seem that many were put away with worn-out batteries at the end of summer, or when replaced with a cheaper-to-run transistor radio (or in the case of the Lady Anne, used on mains with flattish batteries left inside). Leaking carbon-zinc batteries allow ammonium chloride paste to soak through the cardboard, which dissociates into ammonia and hydrogen chloride. The HCl is of course an acid gas and attacks metal.

Many battery radios show signs of chemical corrosion, and I am using a Vidor CN420a attaché case jobbie which needed about 6 valveholder pins replacing (not all on the same valveholder - more the pins on several valveholders facing the same direction on the chassis).
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Old 31st Mar 2016, 10:08 pm   #116
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Default Re: Vidor CN430 My Lady Anne

I think Kalee's analysis of corrosion being caused by acidic fumes is correct. I've worked on many battery sets and found that the corrosion isn't confined to valveholders, and can be found on loudspeaker frames, wavechange switches, steel panels, lid switches and so on.

Thinking about it, another very common fault with battery sets is of an open-circuit output transformer primary winding, which I (and others) have previously put down to excess anode current due to leakage through "that capacitor". It now strikes me that another possibility is the hydrogen chloride gas dissolving in atmospheric moisture to form hydrochloric acid, and then attacking and eating through the very fine copper wires where they are stripped of their protective enamel insulation adjacent to the transformer terminals where they were soldered.
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Old 3rd Apr 2016, 11:34 pm   #117
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Default Re: Vidor CN430 My Lady Anne

Hi all,

Sorry for such a late reply, but I haven't been on the forum for a while so I have only just read through all of your great advice.

There is no doubt that there is an issue with the base for V3. However, there is also a connection issue on the wave change switch. We haven't fully located it yet, but when the set was prone to going silent we moved some of the switch wiring around and it hasn't gone off since, despite being used daily. Hopefully when we do locate the suspect connection it will simply need re-soldering.

That said there is definitely a suspect pin on the base of V3, I am pretty sure one of the forks has broken. So at some point I will need to tackle it, I think I would try the pin replacement approach first.

I am grateful for all of the suggestions offered, so if I continue to have issues I can work my way through each of them. That said I think that as I am faced with lots of options, for now I will be cautious. The set is functioning and working well so I will continue to run it for a while before taking the next step.

I have to say that I am very impressed with this little set, it is loud and works well. For me it looks good too, so I like it a lot. Ultimately what I want to do is listen to these fascinating radios, as much (if not more than) fix them.

One other thing I would like to do, and I am open to advice on this, it build a battery pack for the set. Has anyone attempted this? I'd love to be able to take it on some of my National Trust picnic outings!

Once again, thanks for your advice, it's a great help.

Regards,

Gary

PS. Phil, that Avo 8 is superb, thank you very much indeed.
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Old 4th Apr 2016, 8:57 am   #118
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Default Re: Vidor CN430 My Lady Anne

There's lots of info on DiY battery packs in the forum if you search for it. Even scans of original battery cases for the determined restorer.

The basic approach involves 10 cheap PP3s in series for HT and one or two C or D alkaline cells in parallel for LT unless it's one of the mains/battery sets with series filaments when you'll need 5 AAs in series. With a bit of luck, all can be squeezed into the original battery envelope.

Great fun!
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Old 4th Apr 2016, 9:53 am   #119
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Default Re: Vidor CN430 My Lady Anne

The CN430 uses a single combined HT & LT battery instead of separate HT and LT batteries. I've built battery packs for other radios using PP3s and a single D cell but haven't built one for the CN430. It's not that difficult to make a case out of cardboard but the challenge is to fit the PP3s and AA cells into the space.

When my grandmother had one of these sets she used it once on batteries. After finding out how much the battery cost it spent the rest of its life as a mains powered radio.

Keith
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Old 5th Apr 2016, 12:13 am   #120
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Default Re: Vidor CN430 My Lady Anne

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There's lots of info on DiY battery packs in the forum if you search for it. Even scans of original battery cases for the determined restorer.
Thanks, I think that's the way to go.
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