A spot of
bother - where there's some lifting veneer and missing finish
at the edge of the screen panel...
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
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.
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.
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.
I discover that the veneer on the lid is still in excellent
condition underneath its water-damaged finish.
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...
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...
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.
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.
were a success. Here's the new cabinet label placed next
to the old, which can now be removed.
practicable to place either label on the scanner, so the
bitmaps I've been working with were derived from high-definition
here's the new valve guide label on the chassis placed next
to the one it will replace.
these labels on a slightly yellowed paper to match the originals
as well as possible.
on a detail of the valve label, I've here marked two points
of interest in yellow.
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.
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.
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...
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.
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
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 !
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.
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 !