Teak Acoustic Deluxe. RBM 640 Basket Case!

[MickMcmichael]

Hi all.

I mentioned in my thread about the white Acoustic Deluxe that I had another one in teak which had been donated to me for spares. I didn't actually use any parts from it and so it sat in my workshop looking a little forlorn. I had managed to get it onto the bench for inspection purposes with difficulty. Both sides of the cabinet had become separated from the upper and lower sections of the cabinet and being a 23" tube with a certain amount of weight, I had to hug the damn thing in an upright position to heave it onto the bench.

I started thinking that it might be possible to save it in some way or another. A lot of work would be required but probably worth it in the end. Why scrap it if it can be saved?

So, when I say basket case I'm not actually sure whether I'm referring to the set in the condition that it was in, or to me for wanting to save it!

Some progress has been made. So here's the story. It will come in dribs and drabs due to the vast amount of work that was required at the outset.

Here's a warning to the purists amongst you .... it just can't stay teak. The cabinet is made of plywood with a fake teak paper thin skin stuck over the top, most of which is badly damaged or missing. Some of the ply laminations have dried up and separated and I'm going to need a fair bit of wood glue and filler just to get the cabinet stable. All I will say is that it will end up in one of the original colours used by Murphy for this range of sets.

So stage one was to strip the set out without causing any more damage. Here's the pictures of what I was up against. Luckily the speaker frets were just about intact but were extremely weak and could easily be pushed into the cabinet with only a little pressure. If this happened it would render the set useless as the frets would be very difficult to repair once broken.

I'll explain exactly what I did about this next time - hopefully within the next day or so.

[high_vacuum_house]

At least it doesn't contain a woodworm farm as well

Christopher Capener

[FERNSEH]

I've restored equally bad sets. The problem is finding teak veneers. Perhaps the best idea is repair the cabinet and paint it in one of the Murphy colours, say, quite white or outrageous orange.

DFWB.

[vinrads]

Hi Mick would it be out of the question to make a new cabinet , then paint it I always liked the shiny black ones , I remember these the first time round very futuristic in the day , the speaker grill could be done with a circular saw from the rear plunged to the req depth,whichever way you go good luck with it . Mick.

[neil29]

Why not make it a blue or green version as there's numerous white orange red and black ones about .


Cheers
Neil.

[FERNSEH]

Can't remember the name they gave for the blue cabinets. However, I do remember serene green and dramatic black.
Painting the repaired cabinet is the best approach, unless, you are willing to re-veneer the complete cabinet. The advantage of painting is that car body filler can be used to smooth over the imperfections.

The CRT, is it 23" or 24"

DFWB.

[MickMcmichael]

I think it was smooth blue, serene green, outrageous orange, revolution red and quite white.

It's a 23" crt but the label has gone so I'm not sure of the tube manufacturer. There are several electrical faults to sort, some possibly lopt related.

Indeed, car body filler came in very handy on this one .... plus lots more!

Story to follow...

We had a green one when I where a lad.

[volte-face]

When the first Murphy Acoustic De Luxe models were released for the new 1967 range, which pre-dated the A640 chassis, I believe that they were only available in two models, as Teak (V179UA) and Rosewood (V179UB). The painted colours and the A640 chassis were introduced a little later. The introduction of the A640 chassis would appear not to coincide exactly with the painted versions being launched however, as I'm aware of at least one person who owned a black version pre-dating the A640 internals.

If anyone has any more definitive information regarding the timeline of the early cabinet chassis combinations, I would be interested.

[FERNSEH]

Not designated as the A640 chassis but similar in it's construction, that is with two vertical PCB assemblies was a chassis that employed germanium transistors in the IF amplifier stages. Transistors were of the AF179 series.
The Bush version of the TV161 that employed this chassis was suffixed as GU. It might have been the same for certain Murphy sets.

DFWB.

[MickMcmichael]

As I said previously, the speaker slats were of great importance. A disaster in this department would have been terminal if I'd pressed ahead with other cabinet work.

Although they look reasonably good, the slats had actually suffered the same fate as the rest of the cabinet. The ply laminations were dried out and sepatated and some were broken underneath the outer teak effect. They would have pushed in easily as they had no strength whatsoever.

What to do?

Well I suppose we all have our own way of going about jobs like this. My way here was to attempt strengthening without disturbing the outer slats. You can see in the picture that when the speaker baffle was removed, half of the laminations from the speaker slats came away with it. I'd expected this to happen as the screws holding the speaker baffle in place had rusted into the cabinet and wouldn't budge. I had to drill the heads off the screws and then prise the baffle from the cabinet. This had to be done as a new piece of black speaker cloth would have to be fitted behind the slats after painting or it just wouldn't have looked right.

I went to the pound shop and bought two packets of super glue for a quid each - twenty tubes in all!

I ran the super glue down the side of each slat being careful not to get any on the teak outer. I then placed a piece of flat hardboard over the slats and weighted it down with some iron blocks for just a few minutes. The super glue set rock hard into the ply laminations and the flat board enabled the slats to lie flush with the rest of the cabinet as they were protruding due to having little strength behind them.

I could only do this with two slats at any one time due to the super glue setting pretty quickly once it seeped into the soft, dry ply.

But it worked. After several hours' work the speaker slats were rock hard and nice and flush once more. I could now proceed with the rest of the cabinet work and get to grips with making it look like a tv cabinet once again.

The last picture shows how bad some of the areas were. Think I'm gonna need a lot of wood PVA and filler!

[1100 man]

Totally bonkers: but I love it It's nice to know there are people even more insane than me when it comes to resurrecting a basket case!!
10/10 for even attempting this one: It would have to be 'outrageous orange' for me- only in the 1970's could you sell a bright orange TV: it has to be the coolest decade ever!!
Great restoration which I am following with interest
All the best
Nick

[FERNSEH]

That's good news about the speaker slats. If these couldn't have been fixed then the cabinet restoration just wouldn't be viable. Looking at the last attachment it would appear that the cabinet base has become detached from the side panel. I've repaired quite a few bashed up corners by laying on pieces of veneer until the correct shape has been achieved. Superglue is the best adhesive for this type of task.
I have to say I prefer the appearance of the 23" CRT with it's moulded mask rather than the 24" CRT with the push-through "square screen" presentation.

DFWB.

[jayceebee]

Murphy kept the plastic mask with the Acoustic Deluxe 24" models right through until the introduction of the V2427 which used the solid state A816 chassis. The mask on the 22" CTVs remained until the CV2215.

I have to admit I was never a fan of 23" push through presentation sets or indeed 19" and 25" CTVs and preferred to see a mask, it suited squarer CRTs much better in my opinion.

[volte-face]

Originally Posted by FERNSEH

The Bush version of the TV161 that employed this chassis was suffixed as GU. It might have been the same for certain Murphy sets.

It was. I have an early V179UA (Teak) Acoustic De Luxe and it is fitted with the A571 chassis. The Bush equivalent is the TV145GU. Luckily for me, the cabinet is a little more intact than the subject of this restoration thread!

What interests me, if anybody has any recollections from back in the day, is how many of the early painted models got the A571 chassis before the A640 production took over? Answers on a postcard!

By the way, the TV161GU mentioned uses a main chassis designation of A654.

Looking forward to seeing this cabinet re-veneered back to teak

A couple of pics below - one to show the A571 chassis, the other for inspiration!

[jayceebee]

The two boost capacitor at the bottom of the timebase board gives it away that it isn't the A640, if my memory serves me right is there a pot at the bottom of the signals board to set up the transistor LT supply voltage?

[neil29]

What about the A591 chassis to be found in the likes of the TV141U/TV148U and the Murphy V159U/V153U which has I would have thought an earlier chassis despite the number suggesting otherwise. and the fact they have twin tuners as well as three extra valves in the if section which deal with vision if amp,sound if amp & limiter and common if amp.


Cheers
Neil.

[Welsh Anorak]

That's a good point - I thought the last of the valved IF versions was the TV148U. This must have been an interim set with the germanium transistors. I've never come across one. I assume the 'basket case' is a proper A640.
As a matter of interest, my 2417D in white has a mask round the CRT but is almost 'push-through' in presentation - best (or worst) of both worlds. Wonder why they did it - it's an A61-120 CRT so doesn't need a mask.
The Acoustic design went on for a long time - I was called to a 22" Z718 many years ago in an alarming tomato colour. The room was decorated to match with deep red walls and a black shag pile carpet. Mmm - nice.
Glyn

[MickMcmichael]

And so to the cabinet repair. This was actually all pretty straight forward stuff. Whilst it may look a basket case, it really was just a question of piecing things back together a bit at a time. The various layers of ply were glued and clamped a bit at a time. I had to be careful around the front facia as it is carefully shaped for the push through tube mask so the ply laminations had to be put back exactly where they came from.

Headless tacks were also used to hold the cabinet together and they were used at the top and bottom of the sides where there are strengthening blocks in the corners of the cabinet. I tacked them in below the flush level of the ply and will fill the tiny holes with filler - along with the rest!

Once the cabinet was in one piece, relatively square and sturdy, I was able to start applying the filler ( I say relatively square as the cabinet had warped slightly along the bottom edge so squareness was a bit of a compromise).

Lots of sanding down! Low spots refilled and high spots resanded. I used a comparitively cheap car body filler. It sets quickly and its possible to achieve quite a lot in a couple of hours.

I kept finding bits I'd missed so the process took a while. Finally, it looked like a TV cabinet once more. I reduced the grades of sanding paper as I went along and it was really smooth to the touch.

I could forsee a problem though. The remaining teak areas, although very smooth, still had depth and grain and this would be a problem in trying to achieve a smooth finish. I noticed when I did the white acoustic deluxe that the paint was sprayed onto a nicely smooth veneered surface ( a bit like smooth conti board ). This surface I'm working with now is nothing like the white one and the teak effect definitely has depth and grain.

I sprayed a small area of the set with grey primer ( 4th picture ) and my suspicions were confirmed. You can plainly see where the primer has not covered smoothly due to the effect of the grain.

Well I couldn't press ahead until I'd sorted this. As Deputy Dawg would have said: "Dag-Navitt!"

So I decided to skim the whole cabinet! This would, when smoothed, introduce a nice smooth surface to start spraying. The last picture shows the cabinet covered in hard setting fine surface filler with a whole lotta rubbin' to do!

In the meantime I tried to cheer myself up and get an idea of how it might look when finished. I bought two cans of red spray - the can tops were the perfect colour and I sprayed some onto a piece of primed hardboard. The red was far too dark for an original look so back to the drawing board on colour.

Time to think again but first that cabinet must be smooth!

[MickMcmichael]

Here we are then. Skimmed, sanded and smooth, primed and sprayed. Three coats of orange in all. I used a brand "Painters Touch" and the shade is known as Real Orange.

There are some issues to sort out electrically, one of which I've been on to today. The oversized test card you can see in the last picture was taken in 405 mode. The picture is washed out and looks extremely tubey. If I set the EHT to 19KV with the stability pot the picture is even more oversized than you see here! The line stage just dies when 625 is selected.

I disconnected the overwind and fitted a Thorn 1500 tripler. Excellent on 405 with picture geometry almost perfect but still no 625 operation. I then tried a good lopt from another set and both 405/625 operation normal.

I'll investigate this lopt situation further over the coming days. I've got a few here to play with, all in various states of disrepair. Some with holes in the overwind where the EHT has escaped and some of unknown origin/faults.

Keep watching this space!