Page 3

A spot of bother - where there's some lifting veneer and missing finish at the edge of the screen panel...


...but soon re-secured with superglue and some other minor damage is also made good. All the 'short' restored panels are now done. They'll join the main cabinet parts after these have been finished and then be rubbed down and polished, just before assembly.

On now with the main cabinet restoration job... First I set to work stripping off the old finish with Nitromors and a scraper. This job is best done out of doors for ventilation reasons.

After all the parts have been stripped, they're all given a thorough rub over with coarse wirewool and cellulose thinners. The residue is rapidly wiped off as I work, section-by-section.

This gets rid of the remains of the stripper and stubborn bits of the old finish, and leaves the surface ready for the next stage - sanding along the grain with fine sandpaper.

Fortunately I discover that the veneer on the lid is still in excellent condition underneath its water-damaged finish.

The original black fine hessian material used to cover the back had been badly torn when I acquired the set in the 1980s. I had replaced it with an (earthed) expanded metal grille. Now, I fit new hessian to put it back to original...

The cabinet panels had been displaced by swelling caused by the water damage. So next, I attempt to push them back to their correct positions with cramps. Unfortunately this operation doesn't go well. It now looks like I'd be best advised to leave the stripped cabinet to dry out further for a few weeks in the hope it will return to its original form naturally. The gaps have already started closing...

So tomorrow, I'll start looking at the electronics.


Well er, actually - before I can clean down the electronics I'll have to make sure all the labels can be successfully reproduced first.. So the whole day is taken up with restoring the two damaged labels in PaintShop Pro: one from the floor of the cabinet, one affixed to the chassis.

The third label, a transfer (decal) on the rear of the cabinet is basically good so I've decided to retain it. It was masked off during the stripping phase.


Both operations were a success. Here's the new cabinet label placed next to the old, which can now be removed.

It wasn't practicable to place either label on the scanner, so the bitmaps I've been working with were derived from high-definition digital photographs.

And here's the new valve guide label on the chassis placed next to the one it will replace.

I've printed these labels on a slightly yellowed paper to match the originals as well as possible.

Homing in on a detail of the valve label, I've here marked two points of interest in yellow.

The original label must have dated from the 1936 version of this model. The yellow circle marks the position of where the MH4 'line ring' triode had previously been and which someone had crossed out on this set. This valve had only been fitted to the dual-standard models. It was required to supply line pulses during the field interval - which Baird had neglected to provide with his 240-line system. Without this valve, the picture would tend to 'hook' at the top as the line timebase started to run off-speed.

The cathode ray tube fitted to my example is an Emiscope 6/6. This label states '6/4' though, which must have been the tube fitted to the very earliest models.

Before taking a look at the power supply, this seems to be a good time to clean up the chassis ancillaries and vision strip valve cans. They look better now...

The valve cans will later have new foam rubber discs made up and attached to their tops. These bear into the spar (here seen across the top) which will hold them in place.

 And here's the metal shield that bears the valve guide label, with the newly created version added.

On to the tackling the first of the major internal units: the power supply now. This is the scene of chaos that develops as I remove the various covers and dismantle as much as I can. I

It's essential to take copious digital photos as the work progresses (only a few of which appear here) so that later I'll know how everything should go back together. This has now become my policy for practically every job I do - I find it so helpful later.

Here's the very meaty mains transformer for this television set... This is a good old solid (and heavy!) earthed-chassis circuit - long before the days of droppers, live chasses and eht/line ouput transformers. It's a full 6 inches across !

The modern electrolytics visible date from the '80s. These will later be hidden in a period-style cardboard case.




The two sealed 0.1uF EHT smoothing capacitors in the right-hand block are still connected and are (presumably) in good condition. They'll be megger-tested later before deciding whether to continue with them. The smaller block on the left is the focus voltage decoupling capacitor - also still connected.



EMI thought to look after the safety of any person who ill-advisedly removed the back while the set was powered up. This spring loaded vane has to be pushed in to get the set's back on. When it is 'out' it shorts the final EHT capacitor to earth. In this condition, the whole 5000 volts is then dropped across the 1 Megohm series smoothing resistors, meaning a current of 5mA will be drawn, about ten times the normal peak load, undesirable perhaps, but not as disastrous as the loss of a life !

The story continues... CLICK HERE


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