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Old 17th May 2018, 2:17 pm   #13
Argus25
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Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
Default Re: Firestone TV from ETF auction

Roger,

It is great that it looks all original with the wax paper caps (waxies), and you know the CRT is good so there is no logic in trying to power it initially for a CRT test. (I tend never to power a vintage set with its original waxies & electros anyway, I wait until they are attended to)

My advice is to rebuild every waxy initially. This is because they will all be leaky to some extent and play havoc with the circuitry, especially the coupling cap into the grid of the audio driver (with a 10M grid resistor) and the deflection plate coupling caps into the high load resistors.

Heat the waxies in an oven until the wax just melts, it makes it easier to withdraw the contents from the cardboard tubes. Then wipe off all the wax while its hot and melted.

When you put the poly caps inside (with the same value & often higher voltage rating) wrap tape around each one near its center to make them a firm push fit into the tube. Then on alternate days pour polyester resin into each end (Photo attached). This way the resin doesn't leak past and out the other end. Get a cardboard box and push in small holes for the leads to keep the capacitors stable while the resin sets.

Also, you will find when the hot wax is wiped off each capacitor's tube, the surface will later accept varnish (I use marine spar varnish). This way when it drys, it looks good, but dust does not stick to it unlike the wax.So I do this rather than re-waxing them (Photo of some caps under the chassis of a set being restored attached, the varnish is why the capacitors look a tad shinier than usual).


Mostly I replace the resistors with 2W MF types, but you could check what is there and replace those out of spec. In the RF circuitry (IF's etc) largely its best to use silver mica types. Try to avoid replacing any of the small ceramic capacitors ,such as dogbone caps, in the tuner section, they are mostly special types & usually they are ok.

Replace all the electrolytics with new manufacture ones, the types used in this set, twist lock I think, are available from AES (USA). Then when all that work is done it will be ready to power up & align.

Have fun !
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