[BrendaAnnD]

I just got this interesting GE radio model J-100. This thing is built like a veritable battleship.

The most interesting thing is the rectifier. It's an 82, mercury vapor rectifier. It has the most beautiful blue glow inside the plates. The only other thing I've seen with mercury vapor rectifiers in it was an old Raytheon AM transmitter. Needless to say, I didn't get to look at that rectfier in action. I'm curious as to whether this SHOULD have this beautiful blue glow. Once I put in new power filters the radio plays well and sounds great. Not a hint of hum.

This set also has the most interesting volume control I've ever seen. It's actually a part of the AGC circuit as opposed to being either in the antenna or audio circuits.

http://www.nostalgiaair.org/PagesByModel...015712.pdf

[Mondial]

Yes, it is perfectly normal for a mercury vapor rectifier like the 82 to have the blue glow between the filament and plate. That is the ionized mercury glowing which results in a constant 15 V voltage drop across the tube, pretty much independent of the DC current draw. The constant drop is important because the Class B output stage draws a varying amount of current with audio signal level.

The RCA AVC circuit is very interesting and is somewhat similar to the amplified AGC of the Apex set you were working on a while back. This one uses a separate plate detector to generate the AVC voltage instead of taking it off the regular audio plate detector of the Apex.

[Arran]

That's the ten tube version of one of their deep chassis series sets from 1931-32. While it may have been made by RCA at the time, thanks to the Supreme Court anti trust judgement in 1930, most of the engineering was probably done over at G.E and or Westinghouse.
From what I heard these sets are real thumpers once you get them playing right. I've only worked on the smaller 8 tube Canadian G.E/RCA/Westinghouse chassis from that era and even those are good performers.
Regards
Arran

[BrendaAnnD]

I'm gonna love this radio when it's finished. The audio sounds great even with the speaker just sitting there on my bench. It's sure a PITA to work on, though. All the caps are in one big can, and that can is attached to the chassis with some heavy tabs that I can't seem to bend away from the chassis. I've replaced the filters by cutting the wires coming out of that box for now.

The cabinet work may be a bit much for me.. it needs pretty much all the veneer replaced, especially on the front, where someone has just painted it all flat black and there's a lot missing. The bell has holes drilled in it on both sides, but that will be fairly simple in comparison, as I can just take a single piece of new veneer and apply it to the whole thing.

[Phlogiston]

This R-78 BI-Acoustic also uses the 82. It is capable of producing incredible levels of audio. I can't imagine anyone ever running it that loud. It is a 12 tube unit.

Be careful. Many of the GEs and RCAs of the time started to use photofinish. It looks good, way better than what Philco used, but it is all still fake.

   

[BrendaAnnD]

Photofinish or not is nonsequitor in this case, as I said, it's all been painted flat black on the front, and large pieces of veneer are missing.

               

[Phlogiston]

You need another cabinet.

[codefox1]

I'd be tempted to use Bondo, and then an outrageous Red or Orange Engine Enamel experiment or blend (until of course I found a better cabinet.) The insides will not care.

[BrendaAnnD]

Don't know where I would find another cabinet. I've never seen another of these radios. They're rare enough that service literature for the exact model is not available, only schematics for the RCA version. I figure even at my skill level (2 of 10) I can do right by this cabinet. Since the side moldings are missing completely, it will give me a chance to use my router table for something besides more shelf space.

[jerryhawthorne]

Brenda, go for it. The top/sides are easy, just wrap some new veneer over the existing after filling the holes. The front, a real challenge. I'm not that good on cabinet stuff (well any of that stuff) but the front scares me. Please post your progress. Remember, the journey is the real adventure. The longer it takes to the destination, well, the less radio projects you need to buy.
Looking forward to your journey.
Jerry

[Arran]

The good news is that I don't think it had much, if any, faux finish to begin with, I think that there may have been some in the form of a birdseye maple on the front. If you want to have a go at replicating moldings take your time, they probably used poplar or maple to make them out of, if a piece looks wrong, chuck it and make another. I would say that when it comes to cabinetry about 10-20% is measurement and planning, the rest is from experience gained through lots of practice. It would be helpful if you could find someone who has a good cabinet to copy from.
One thing that you may have to do is custom grind a router bit or two to get the right profile, or do a lot of hunting, the typical router bits they sell at a hardware store seldom match.
That set is the big brother to my K-83, except it is not as common, but at least the hard to find bits like the escutcheon and the knobs are there. There is also no shame in farming out some if not all of the work to someone like Steve Davis, unless there is a Korean version of Steve in your area.
Regards
Arran

[codefox1]

Agree with all except myself. Dunno if you speak the local language, but maybe you could hire a cab driver to find some little old craftsperson who still putters with wood and veneers and get the cabinet restored very nicely for not all that much money. The experience would be worth ten times the price. Never wandered around Korea, but China and Taiwan, Viet Nam, etcetera ad nauseum did. So don't paint it up with heart attack colors and put it in your rest room, I withdraw my recommendation. Yup, Navy.