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B&W TV Murphy A640 Acoustic de-luxe rebuild

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slidertogrid
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This is the set I mentioned in the upcycle thread. I have been looking for an A640 Acoustic - deluxe for a while preferably an orange or red one.  There have been occasional ones on ebay but they were too far away and in a couple of cases they made a fair old sum! 

This came up for sale a couple of years ago within a reasonable distance and a fairly low price due to the fact that it had been stripped out for parts. What I got was a cabinet, Tube and back cover when I collected the set the seller gave me a tuner mechanism with mounting bracket just the mechanical part no electronics.

It has sat under my bench waiting it's day since. I had some parts to rebuild it which I have saved from scrapped sets. firstly I cleaned the tuner mech and fitted the tuners that I removed from a scrap tuner that had been robbed of mechanical parts, I found some buttons and springs and fitted it to the cabinet. There was a speaker but no transformer so that was found and fitted coming from the 19" set I scrapped that had woodworm. then a set of  scan coils and the chassis from the same scrap set. That woodworm eaten set has now donated it's parts to save three sets and I still have the tube as a spare.

Next the LOPT I had a A640 LOPT that had a duff overwind and a A774 LOPT with a good one. So after a bit of bodgery I had a complete LOPT for the A640.

This FrankenMurphy was then gently given some power. I still need to find a bracket to mount the on/off volume control as it is different on the Acoustic de luxe to the one that is fitted to the chassis. I may have to make one.

After a bit of playing around with system switches and tuner switches I have a picture! No sync, No sound and the contrast varies by itself, it will only tune on UHF I can't get any signals on Band 1 at all but the tuner was a scrapper and quite rusty so I will have to look into that. It does at least go through the motions of band switching and tuning.

I am pleased that the tube looks to be good as all the fixing bolts were loose and the rimband earth lead was disconnected so I had feared it was a dud that had been fitted. 

The Acoustic de-luxe is slowly coming back to life... It's a bitza admittedly but at least it has been saved as a TV and not a Fish tank or cat bed and it has made good use of the parts I had in store. 

Just a bit to do to finish off which i will get on with, it has waited long enough!

20230811 131725
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Posted : 16/08/2023 4:11 pm
ntscuser, Nuvistor, Cathovisor and 2 people reacted
colourstar
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Good work Rich, that's a really interesting project. As dual standard b&w sets are very much my thing, I'd been looking at the orange Murphy fish-tank abomination that's currently on offer and wondering whether it was worth acquiring (at a decent price) and putting to one side in the hope that either a scruffy A640 donor set or it's component parts ever turn up. However, it's 2023 and I'm not sure how likely that is now. I did contact the seller of the orange set on the 2.3% chance that the crt, chassis and cabinet back are still around, but unfortuately they were discarded.

 
Posted : 17/08/2023 8:05 am
slidertogrid
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@colourstar   I have the back from the 19" set I dismantled which you are welcome to if you do decide to go for it. The back will fit but you will need to add a flat piece to cover the speaker part of the cabinet I think.  I have a bare chassis with wiring, frame transformer and dropper but no panels LOPT or volume control. And a spare set of scan coils which you are also welcome to.  I do also have some brackets in the box that the spare tube is in, I think they are the tube mounting brackets and of course the tube if you need it.

So there is a start if you fancy a challenge! The A640 does seem a little prone to woodworm so another basket case may turn up. The white one I saved that I posted about on the other forum was found by a skip at a house clearance place so they are out there...

I dismantled a 19" that was falling apart with woodworm which saved three other sets and a 23" 'Top Rank' model which was full of live worm, it looked as if it had been blasted with a shotgun! That set had been in a damp shed and was incomplete but again it saved two others, the tube went in a earlier set, the one with the valve IF panel. 591 chassis? The tuner electronics went into this set and the back cover went to my mate Mick who has rebuilt a 23" Acoustic deluxe which was a backless wreck. That set ended up orange and is subject to a thread on the UKVRRR .

Teak Acoustic Deluxe. RBM 640 Basket Case! - UK Vintage Radio Repair and Restoration Discussion Forum (vintage-radio.net)

It may be worth contacting Neil on this forum I think he said he had a spares set A640 again full of worm, maybe he can help with parts as well? 

Good luck if you decide to go for it! It would be a hell of a save! And would give you instant membership to the "Downcyclers'" movement.... 😀 😎

Rich 

 
Posted : 17/08/2023 9:06 am
neil1974
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Hello all.  I can certainly help out with the panels and a tuner and even a speaker if needed and possibly a volume control if i can find it. but i think that's my limit unfortunately because i've used bits from the wormy TV166U for a couple of other sets. but if you still want them Steve then you're welcome to them.

 

Cheers

Neil.

 
Posted : 17/08/2023 11:41 am
slidertogrid
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Nice one Neil. So between us I think we have enough parts to make the set pretty much complete. We may be a bracket or two short of an A640.... 😀 But I'm sure they could be remade we have at least got ones that could be copied.

I wonder if the seller will take a low offer? This set exactly demonstrates the folly of upcycling if the set had been left as it was it would have made hundreds. As it is the owner doesn't want it as as a fish tank hence the sale and it hasn't so far sold. If it had been original and put up for sale at say £200 it would have sold very quickly. 

@colourstar What do you think? 

 
Posted : 17/08/2023 12:23 pm
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colourstar
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Well, it's beginning to sound a bit like a plan! Thanks Rich and thanks Neil. It would be massively satisfying to downcycle an upcycle. It would also be great to be able to say to the seller "I'll take it, but you can keep the fish tank!" It depends on whether he'd take a lower offer. I'll have to consider my options.

 
Posted : 17/08/2023 12:55 pm
slidertogrid
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It will be the small parts that will be the hardest to find if a donor set can't be found. I have checked the box that has the tube in in there are only two tube mounting brackets the other two must have gone with the remains of the cabinet. Even then there is no telling if these brackets will suit the Acoustic deluxe cabinet. 

 
Posted : 17/08/2023 2:10 pm
slidertogrid
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The set is coming back to life slowly. I spent a couple of hours in the workshop today. After a bit of tail chasing, a few capacitors a few resistors and a couple of valves we have sound and reasonably stable vision! Dry joints and a dodgy valve holder was the contrast problem, it dropped off after a while, came back and then dropped off again. All over the place! The PFL200 I fitted is also a bit suspect despite being new. It has a good old Mullard in it at the moment. 

The lack of sound was just a clapped out PCL82. The line hold controls and height control are intermittent. I have fitted a temporary pot to the height, the others are reasonable after a clean. 

I still have nothing on VHF which I will come back to but UHF is fair, The picture sways as if the smoothing is impaired but splashing the smoothing capacitors makes no difference. ISTR the flywheel diodes can cause this problem but the usual diode block has been replaced with separate diodes so maybe not in this case? 

At least the tube is a belter! 

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Posted : 17/08/2023 5:10 pm
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Nuvistor
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@slidertogrid 
Try and put some series resistors with those diodes as per RBM builtin, 15-22k will be ok, perhaps not this fault but they cause all sorts of funny problems without them. The originals were selenium with corresponding forward resistance.

Could the waviness be a h/c leak in the line osc valve?

 

Frank

 
Posted : 17/08/2023 7:30 pm
slidertogrid
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Thanks Frank I will give it a try, I'll try another valve first. 😎 

 
Posted : 17/08/2023 7:58 pm
colourstar
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Just as an update on the orange Murphy fish-tank conversion. I offered the seller £50 for the tv shell on the basis that he could keep the fish tank set-up and sell that separately if he wanted. The silence was deafening! I don't know what I should be paying for an empty case but I really don't think I can justify more than fifty quid (unless anyone thinks different). Its a shame as thanks to offers of help from Rich and Neil I would have nearly everything to put the set back to original, which would be incredibly satisfying.

 
Posted : 25/08/2023 8:17 pm
Cathovisor
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@colourstar I don't think you need me to tell you that in all walks of life, some folk have a very inflated idea of what something is worth and will steadfastly refuse to move from it.

"It's just the right person hasn't turned up yet" doesn't really work.

 
Posted : 25/08/2023 8:28 pm
neil1974
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Hi Steve,  Do you have an A640 at the moment? if not i've got one here if you want it.  its a 23" acoustic in a dark finish that you might want to possibly repaint in a more cheery colour if the mood takes you. and you can have it FOC. the only problem is how to collect it from me.

Cheers

Neil.

 

 
Posted : 25/08/2023 8:57 pm
colourstar
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Hi Neil,

Wow that's a very generous offer. I haven't had an A640 for some years and have never owned an Acoustic Deluxe. It sounds like a good excuse to visit your neck of the woods, although I would most definitely pay you for the set. Is it a teak finish or one of the colours?

Its always possible the owner of the orange Murphy may relent and accept an offer at some point if his contraption doesn't sell in the coming weeks/months. As Cathovisor says, some people pluck a random amount that they think these things are worth and that's that. They will hold out until the end of time and the adverts just stay hanging there forever, never dropping in price.

 
Posted : 26/08/2023 7:56 am
neil1974
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Hi Steve.  Its not teak its much darker than that. but i cant remember what its actually called.

Cheers

Neil.

 
Posted : 26/08/2023 8:35 pm
Cathovisor
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There was one colour that got forgotten in the "coloured" range - Gentle Grey.

But if it's a veneered set, I'm not sure; sadly there's a gap between 1970 and 1973 in Dave Grant's catalogues and the only veneer on offer was teak.

 
Posted : 26/08/2023 9:50 pm
neil1974
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I've had a look at the murphy site and it looks like rosewood?.

Cheers

Neil.

 
Posted : 27/08/2023 11:52 am
slidertogrid
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It is a hell of a job to paint a woodgrain set, see the thread Mick posted on UKVRR. I know his cabinet was a wreck but even after he had repaired it he had a game filling the woodgrain to get a smooth finish to paint.  If the set is in good condition I would say it is probably best kept as is... 

https://www.vintage-radio.net/forum/showthread.php?t=137894

 
Posted : 27/08/2023 3:49 pm
Cathovisor
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@slidertogrid If you're going to overpaint anything like this, to get a smooth finish grain-filling is a must - but at least you don't have to tint it if you're painting it!

Rosewood seems a very unusual (and expensive) choice for a veneer though so if it is, it's worth preserving. Bush were very fond of something called Tropical Olive.

 
Posted : 27/08/2023 8:04 pm
colourstar
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Personally I rather like the woodgrain versions of the Acoustic range. Very stylish indeed!

 
Posted : 27/08/2023 8:07 pm
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