Vintage Tube Radio restoration

[Bubba57]

Ah, rubber wire. I had that joy in my 1939 Philco. I had to replace all of it, and rebuild the light sockets on the front for the channel selection indicator. Handily there was a tech document on philcorepairbench on how to do that with easily sourced bits from the hardware store.

Yeah gadget as I told Gregg the wiring on this wasn't bad but this thang has a **** pot load of capacitors in it. But talking about the rubber wiring, I just finished a Admiral 4201-B6, I think it is 1941 model, and every wire in that thang was so brittle you touch it and it would turn to powder. Even the wires going up into the IF cans were that way. I would hate to thank what would happen if somebody would have plugged it in..and as you said, this one even the light socket wires had no insulation

Thanks gadget for your help

Bubba57

 

[mrphilco]

...and here I am!

I have seen many of those postwar Philcos with scorched diffusers, but believe it or not, I've never replaced one...but I've seen some good suggestions earlier in this thread...

Bubba57, I can tell you to get rid of the problem that caused the burnt diffuser (incandescent night light bulb) and replace it with an LED. When you do, try to bend the dial lamp bracket so that the LED night light bulb does not touch your new diffuser. The LED will not produce as much heat, but why take chances?

Good luck.

 

[AlTinkster92]

Don't forget there's VideoKarma available in the main listings. There is a great antique radio Forum in there that's very helpful. Full of old radio guys..... Al

 

[ggregg]

Most old TV guys were (and many still are) old radio guys. Videokarma is a great site. So is ARF (Antique Radio Forum). All radio guys there.

 

[Sam Cogley]

You can always take a piece of plastic that is otherwise suitable and lightly sand the surface to scuff it up. This is one way to add a diffuser to clear LEDs. And speaking of LEDs, that's one way to avoid excess heat on the rebuild. Styrene, alas, is a very poor plastic for longevity. It is brittle, poorly ages, and has low heat tolerance. ABS is better, but not good in a high-heat environment. Some of the high-impact plastics designed for outdoor use are far better and will last a very long time.

I have found that custom lighting services and sign makers have all sorts of plastic bits and pieces left over from installations and will often just give you a piece from the junk bin. You can find ones local to you with the Thomas Register ( www.thomasnet.com ) doing a local search or with the yellow pages. Hand the worker who fished it out a tip and life is good for everyone.

An easy way to diffuse LEDs is to paint the surface of the LED with liquid CA adhesive (super glue), then drop it in a small container of baking powder. Makes a nice frosted surface.

 

[Retrovert]

An easy way to diffuse LEDs is to paint the surface of the LED with liquid CA adhesive (super glue), then drop it in a small container of baking powder. Makes a nice frosted surface.

Sodium bicarbonate is hygroscopic so it will pull moisture out of the air so I don't know how durable that will be. CA also is not hydrolytically stable so any moisture picked up by the bicarb would tend to break it down. A light spray with polyurethane varnish should seal the surface against that.

Going forward with this idea, what about using the plastic dust produced from sandpaper? That would be fine particles to diffuse the light. And using a little epoxy, which is incredibly stable, would ensure the LED outlasts everyone.

I just missed my patent opportunity for LED panko with an epoxy wash. Oh how foolish of me...

Mmmmm, LED panko with epoxy wash.... (slobbering sound)

 

[gadget73]

Can't you just shoot it with a mist coat of white paint to act as a diffuser?

 

[Sam Cogley]

Sodium bicarbonate is hygroscopic so it will pull moisture out of the air so I don't know how durable that will be. CA also is not hydrolytically stable so any moisture picked up by the bicarb would tend to break it down. A light spray with polyurethane varnish should seal the surface against that.

Going forward with this idea, what about using the plastic dust produced from sandpaper? That would be fine particles to diffuse the light. And using a little epoxy, which is incredibly stable, would ensure the LED outlasts everyone.

I just missed my patent opportunity for LED panko with an epoxy wash. Oh how foolish of me...

Mmmmm, LED panko with epoxy wash.... (slobbering sound)

CA sets in the presence of moisture. I've done that trick to a few LEDs, the CA seems to seal it all up pretty well. Haven't noticed any issues. Picked up the trick from these threads several years back:
http://audiokarma.org/forums/index.php?threads/led-conversion-a-different-way.215824/
http://audiokarma.org/forums/index.php?threads/led-lamps-make-or-just-buy-them.581438/

 

[Old Guy8]

I wonder how mica would look as a diffuser. Was used in wood burning stoves.

 

[Retrovert]

CA sets in the presence of moisture. I've done that trick to a few LEDs, the CA seems to seal it all up pretty well. Haven't noticed any issues. Picked up the trick from these threads several years back:

Yes, correct, cyanoacrylates (CA) polymerize in the presence of water. That's not because of the water, per se, it's because the CA polymerizes when a weak base, like the hydroxide ions in water, neutralizes the weak acid added to the CA solution to prevent polymerization in the vial. If the items being bonded are too alkaline (or have too much water around) the bond rapidly polymerizes which weakens the resulting polymer. It also generates a lot of heat. That is why the mythology developed of not using CA to glue cuts because of the risk of burns.

CA also breaks down in the presence of water and loses its adhesion. Surgical glue had to be reformulated. Some of the formulations are stable enough to be used under water, others not so much. I know from gluing cuts back together (oh, sure, like you could master a butterfly knife without any cuts) that it doesn't adhere for very long because of the moisture in the skin. That's why I try to use surgical glue, but it isn't always handy. CA usually is.