FOR OUR HOME PAGE
CLICK ON THE RIGHT


  RESTORATION OF AN H.M.V 907 TELEVISION SET FROM 1938
                                            Page 1

.
PLEASE NOTE THE LINKS BELOW WILL ONLY WORK WHEN THERE IS CONTENT ON THE RELEVANT PAGES.
Television Set

HIS MASTER'S VOICE  907
Unveiled at the Radio Olympia show in 1938, the HMV 907 (along with its stable-mate the Marconi 709) were examples of the second generation of EMI television  receivers. This particular model included all-wave radio. The first generation models continued alongside. The new entrants extended the range and attempted to broaden the appeal of television to the public with their new lower prices. In general, the savings were made by reducing the screen sizes. 5-inch, 7-inch, and this new 9-inch model became available alongside the earlier, 9-inch and 12-inch models. The strategy proved successful, and by mid-1939 television sales were poised to 'take off' in Great Britain. The B.B.C Television Service, radiating from Alexandra Palace, was by now well-established. World War II then intervened, and ownership of television receivers didn't reach 1939 levels again until 1948.



Here's the set as presented for restoration. It's reasonably complete with all the correct knobs, though the rims of some of these will require repair where they have suffered from past attempts at being levered off.

The cabinet is to be completely re-finished. There are problems with lifting veneer and missing pieces of veneer at the top.

The tube is known to be low. At some stage this will have to be taken to France to be refurbished.

 

This is the view looking in at the back. The two chassis still retain their pre-war magnificence but also show clear signs of more recent attention...

The massive upper chassis unit, containing all the gear except for the power supplies, is removed.

Here's the power chassis. There are (were) two mains transformers - one for the high tension and low tension, and one (to the left) for the EHT for the tube. This has lost one of its windings!
This must have something to with it! Another large, more recent, mains transformer is found tacked in further forward with some crooked self-tapping screws.

 Last to come out of the cabinet is the tube. For safety the cabinet is placed on its face and the two supporting spars are removed first.

Care will be taken to preserve all the labels, whether on tags or stuck to the cabinet. The cabinet label on the right clearly will need replacing. For historical preservation reasons, the old damaged label will remain hidden behind the new.

The top of this cabinet is quite badly damaged. There are pieces of veneer missing and also the main central piece is lifting at its edge. Complete re-veneering is not necessary or desirable in a case like this, since the area of damage is relatively small and maintaining originality of the whole cabinet is important.

Before shaped pieces of new veneer can be inserted and the central piece re-secured with Scotch Glue, the cabinet will have to be stripped. Care will be necessary to ensure the stripping process doesn't further damage the existing loose edges of the veneers.

There is also past evidence of a large potted plant! Some bleaching of stains in the top will likely be necessary - I'll evaluate the situation after the stripping. Still further on, various 'tricks' will be used to conceal where the new pieces of veneer abut the old.

 Damping the top veneers reveals all is not well with their adherence to the underneath, in many places. In practice, there is now little choice but to lift the main veneer and re-stick...

The cabinet's original cellulose finish is now stripped off.

Then heat is applied to the problematic area - the top - with an iron and a thin separator blade used tp part the veneer. This proves to be in two strips, side-by-side. Since these strips pass right over and down the entire cabinet we can't remove then completely but have to curl them back at the top face only. We can see this particular potted plant has made its presence known deeper still !

But this doesn't matter - we'll never be able to see this when the veneer is replaced. This, in the meantime, has been selctively bleached to remove the stains.

Scotch Glue is warmed up and applied with a brush. This is likely to have been the original material used to mount the veneers.

The original veneer is made supple by brushing on water and a weak solution of Scotch Glue, particularly on its underside.

The veneer is placed back onto the cabinet. Once the Scotch Glue has 'taken', it's most important to re-warm it from above (to soften the glue) then to run over it firmly with a Veneering Hammer. This acts as a sort of squeegee and pushes the surplus glue out from the edges. In so doing, the adhesion is improved and the basic flatness of the veneer established. The process is then repeated the next morning. It's interesting to reflect that the use of a more modern adhesive in this tricky operation would almost certainly have led to disaster!

This order of events differs somewhat from that found in textbooks - because here we are re-sticking an old, essentially crinkly veneer - rather than laying a flat, brand new one.

The largest areas of damage on the side-banding veneers are now cut out and new pieces of veneer glued in.

 Phew! The veneers are looking a lot better now and they are properly bonded to the cabinet, unlike before. The brown marks are where some (as yet unsanded) Plastic Wood can be seen, either side of the new pieces inserted into the side-banding.

The cabinet surfaces are still to be rubbed down and prepared for finishing - that comes next...

Rubbing down this huge cabinet takes up the best part of a day. I rub always in the direction of the grain, starting with a medium paper and finishing on a fine. Well... actually it is permissible in rare instances to rub across the grain - when there is a deep scratch to remove that lies across the grain. However one must always be very careful doing this; finish off in the direction of the grain to remove the marks, and be sure not to create a dip on the surface that would later become very visible under the gloss finish. Using a block with the paper toward the end of the process helps ensure general flatness.

Finally, there is no match for running a sensitive finger over the prepared surface. This reveals even the slightest ripples or imperfections in the smoothness and ensures any repaired areas are up to spec.

 One of the several problems with this cabinet includes woodworm around the lower areas. This will be pressure injected shortly.

Also, at this stage I roughly fill the larger areas which have been previously damaged with plastic wood. Here we see a 'wodge' of it along the bottom of the cabinet. This won't be the most visible of areas later but it's still important to get this profile right. Attention to detail makes all the difference to the final impression.

Later, when the cabinet is being finally prepared to take the new finish, I'll return and do the detail shaping work.

One of the requests from the customer is to attend to a the minor matter that the two bottom skirts - or plinths (call them what you will) - are of unequal length. It appears one of them has been rebuilt in the past. This has been done quite well, but the new one is about ¼ inch longer than the other! I have to put this right.

The errant plinth comes off without too much trouble. It's held by long screws.

The story continues... click here...

THIS PAGE MAY HAVE OPENED IN A NEW WINDOW.  CLOSING IT WILL RETURN YOU TO THE MAIN SITE.
   
RADIOCRAFT
Main Street, Sedgeberrow, WR11 7UF, United Kingdom.
Click HERE to email us.