Truetone 513 - 1940

Restoration complete!

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This is an early boom box! You can plug it in an AC socket or use two 45V batteries
that are stored in the cabinet! A switch on the front selects the power source, AC-DC
or battery. This radio was made for TrueTone by the Belmont Radio Corp. Tubes used:
1A7GT converter, 1N5GT I.F. amp, 1H5GT A.V.C. and 1st audio, 1A5GT output amp,
35Z5GT rectifier and 5459 ballast.
 
Here are some pictures of the radio as I received it.

   
The case wasn't in all that bad of shape. The veneer was all intact and the stain actually
looked good close up. The main problem was the lacquer finish was flaking off. So I decided
to try something I hadnít done before but read about in the news group rec.antiques.radio+phono.
I mixed a 50/50 solution of lacquer thinner and denatured alcohol and using 00 steel wool I
rubbed the finish. It went well. It re-flowed the lacquer nicely and left the stain alone. It
dried fast and afterwards I lightly went over it with dry 00 steel wool. I then gave it a couple
of light coats of new gloss lacquer. I liked the way this technique worked and will use it again
with any radio that's in good shape except for the lacquer finish flaking.

The handle had some nicks in it and I gave it several coats of Behlen Master Toner walnut lacquer.

   
You can see this radio is a bit taller than most as the two 45 volt B+ and one 6 Volt A+ batteries are stored under the chassis.


After removing the chassis I discovered a rather large sheet of asbestos stapled to the inside top of the cabinet. Geez I hate that. Usually you can coat it with some glue to seal the fibers. However if I can I like to get rid of it. Some times it doesnít really seem necessary where they put it. This radio actually had 2 sheets. One right on the inside top and another bent to form a pocket of ait between it and the top piece. I did not take a good picture of it but you can see it hanging down in the above picture. Inside it sort of looks like this:
             top sheet -->   __________________
        bottom sheet -->  |__air pocket__|
The asbestos sheets were in not real bad shape and I thought Iíd just coat them with glue. The staples that attached them to the cabinet werenít in all the way so using a needle nose it was easy to pull them out. For some reason I changed my mind and sprayed them with water, bagged and disposed of them without giving it a second thought. Humm, this may become a problem.
 
Here is a pic of the front grill. It's made of wire with some sort of material that looks something like felt on it! It wore off on the exposed center part. I don't think there's any way to find or recreate the material. So I covered it with the generic brown pattern #49 from Antique Radio Grill Cloth.
   
Inside on the chassis is another hidden main AC-DC on/off switch.

   
Pictures of the chassis. The black cylinder with holes to the left front is a ballast tube.

   
Before and after recapping.

After recapping and replacing the AC power cord I plugged the radio into an AC outlet and gave it the dim bulb test. It passed and I removed the tester and fired it up to listen. The radio played well. I left it running for a while as I was able to pick up my favorite but low watt local station, KLBB, 1400. They play oldies. Not 60ís and 70ís like some. Real oldies, 40ís and 50ís. Sinatra, Nat King Cole, Bing Crosby and the like.

At some point I moved my arm over the chassis, and wow was it hot! The heat was coming from the ballast tube, that black cylinder on the chassis picture with the holes in it. I put a grill thermometer on top of it for 30 minutes and it registered 300 degrees! Yikes! Thatís why the two sheets of asbestos were in the radio. Shoot, I had to replace it with something, but what? I checked my favorite source rec.antiques.radio+phono and oddly came up with nothing. I found some discussions on asbestos replacement, but nothing definite. Someone mentioned ceramic cloth and Kevlar, but I couldnít find anything reasonably priced on the net.

I then searched the net for something suitable and stumbled on a product called HotSpot Potholders. They are made of silicone, flexible and are heat and flame resistant to 675 degrees! Wow. I went to a local department store and picked one up. Just $7.00 for a 7 inch square piece and they come in a multitude of colors. They had a nice brown one that matched the inside wood color to a tee, but I went with the white one to better resemble the asbestos that I had removed.

Before I installed it I did a test. I placed it about ĺ inch above the ballast tube and placed the grill thermometer on top of the potholder. I then fired up the radio and let it run for about a half hour. the thermometer registered about 100 degrees. I guess the resistant to 675 degree means it won't be distroyed under 675 degrees. However a constant 300 degrees on one side is 100 on the other. Well I went with it any ways. I didnít staple it smooth to the top of the chassis. I opted to push the sides together a bit in sort of a lazy U shape to form an air pocket some what like Belmont used, but with only one piece. After assembling the radio back in the chassis and running it for about an hour, the top of the wood case is a bit warm. I can leave my hand on the case, but it is a little hot. Although not much more than an old Philco 40-120 that I have. Guess what I should have done was used two pieces as Belmont. One across the top and then a lazy U with a second piece under it. Maybe Iíll change it someday.

From looking at the schematic there are two wire resistors in the ballast tube. One is in series with the rectifier tube filament since it is a 150ma tube. So this must drop the remainder of the line voltage. Thatís 115V-35V=80V and at 150ma that must be 12 watts. The other resistor is in series with the other tube filaments since they are all 50ma. The circuit feeds 6 volts to them, (they are 1.4V filaments, 1.4*4=5.6V), so it must drop the rectifier tube output less the 6 volts for the filanents. The rectifier output is 115V so thatís 115V-6V=109V to drop and at 50ma thatís about 5.45 watts. So over 17 watts of power is being dissipated by the ballast tube. Maybe With the heat generated by the ballast tube Iíll run this with my 90V battery eliminator I built to power my battery only Northern Electric B4100 that I have. Itís A+ voltage is preset for 1.4V, but I could run the filament string for this radio off a 6V lantern battery. At least I have options.





Well it's playing once again and with some new grill cloth, it's looking good!
It's now ready to join my other radios, playing the sweet sound of music. Just
as this radio was originally made to do.
- Mike

For anyone interested, here is the schematic
and service data for this radio.

Rider PDF File   - Thank You Nostalgia Air !

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