My latest restoration of the week. The Philips Monoknob model 787 A/X 701 A/X 785 A/X
October 2002
This set came to me for
a full restoration. It could take more than a week. These sets were very advanced
for their time, this model was the de 
luxe
version with a console cabinet. I am looking forward to this job as I've not
worked on one before. First dismantle and see the inside. Remove all the chassis
bolts, find and unscrew the 2 very small grubscrews which secure the large
wavechange knob, these can be hard to see hidden by 50 years of dirt. The
chassis should then slide out. The big problem with these later Philips models
is the rubber insulation to all the wiring, the rubber can perish and just
crumble away, making a major job. There is no sign of the problem with this
one. Give it a good clean up and lubrication especially in and around the
mono knob mechanism check for shorts and bring the mains up with the variac.
It's working, of sorts, it needs dial bulbs, a new magic eye, and the valve
holders and band switches cleaning.....
A new magic eye required
these valves never last very long and just go dim. It makes the world of difference
with a new one fitted. A good supply 
of
old valves is Jim Fish. His phone number is 01484 654650, always friendly
and helpful. The original is a 4 volt side contact type, there will be no
chance of finding one of these, so I will have to change the base to an EM34
and fit a small 6 volt transformer for the heater supply. These valves are
getting quite rare and I have paid £30 for a good second hand one.
The cabinet is pretty rough, and will require more than a touch in and polish. In particular the top section, where the lacquer finish has been discolored by sunlight and is flaking badly. The whole of the top section will be striped off with paint stripper and very fine steel wool, This is pretty drastic and time consuming but worth it in the end. After the steel wool neutralize the wood with white spirit and leave to dry carry out any repairs to the wood and touch in any blemishes with acrylic paints. The newly exposed grain of the wood must now be filled and sanded to provide a perfect surface for the new lacquer finish. Paint the exposed plywood end grain with a matching dark brown acrylic paint. If you need to mask off any areas use easy release masking tape, this will protect your work by not pulling off layers already applied. Clean off all the dust with a clean linen cloth soaked with methilated spirit, this degreases and dries the cabinet. Then finally a tack rag to remove the last particles of dust, Use wood stains and colored toners to obtain the desired effects. Then the final lacquer finish. I use a cellulose based lacquer, the modern acrylic is not so easy to use and the finish not quite as fine. Spray outdoors on a fine sunny day, rig up a bench with cramps and batons so that the cabinet can be rotated easily without touching the soft lacquer, then you can spray onto a horizontal surface, this prevents runs and enables more cellulose to be sprayed, and the finish can be built up quickly. After 2 weeks to allow the cellulose to cure, flat down the surface with fine wire wool, then burnish with T Cut............ Brilliant.
All the materials are available from a company called Morrels. Look in Yellow Pages. Or on line. http://www.morrells-woodfinishes.com/ If you can make up a small order they will even deliver free of charge. My thanks to Gary Tempest for his super article in the B.V.W.S. Bulletin. (Refinishing radio cabinets)
The tuning scale has been dismantled, spring cleaned, and assembled with a new magic eye, new dial lights, and a repainted cursor. Great care must be taken when cleaning the underside of the scale, if done with too much vigor all the delicate station names can easily be rubbed off, if in doubt take a scan of it first. The large 10 inch permanent magnet loud speaker shown below looks very advanced for its time .
This is my favorite time in the development of early radio, manufactures were all so proud of their products, and were in competition with so many set makers to produce the best performance with the most luxuriously styled cabinets. This set has a full vision scale with names, and wave lengths, reverse feedback circuit, base compensation, and bass control. Variable selectivity, and the magic eye tuning indicator, and in real terms it cost an absolute fortune.
I will show a photo of the complete set when finished.
17/4/03 here it is. Art deco or what?
