(Click on the images for a larger size picture.)

RCA R-70
This is an RCA model R-70 from 1933.  It is a seven tube superhet with three 58's, two 56's, a 47 and an 80.  It is BC only with RF amplifier. 

I picked this up at a swap meet in Henderson, Kentucky in 1994.

The cabinet was in pretty good shape.  I only needed to remove the top coats of lacquer, touch up the accents and reapply about four coats of new clear gloss lacquer, sanding after each coat.  The brass escutcheon had turned black, so I removed it, cleaned it with Ajax, polished it with Brasso then put it in a pie pan with some vinegar and heated it in the oven at 250 degrees for about 30 minutes.   After removing from the oven, I buffed it to bring out the highlights then coated it with two thin coats of clear mat lacquer before reinstalling.  This technique usually works on most old brass parts to give it a nice aged patina.  The dial scale was another story though.  Made of paper, it had been exposed to water at some time and had several stains on it.  It was also warped and had a piece missing.  I was able to drill out the tiny rivets that held it to the backplate and make a copy of it onto white paper with a copy machine.  I then removed the staining and other defects with Whiteout then made a copy of this onto tan colored stiff card stock.  After carefully cutting it out, I soaked it in some strong tea to give it an almost original color.  I then dried it thoroughly, punched out the mounting holes and apply two thin coats of clear mat lacquer.  I remounted it with 4-40 hardware.  The whole dial now looks like new.  I was able to save the original grill cloth by removing it, washing then stretching it onto a new cardboard frame I had made.  I then reinstalled it behind the grill.  You should always try to save the original grill cloth.  Yes, I have replaced them with reproductions, but only as a last resort.  I can always tell a repro. when I see one.

The chassis had those metal cans on the underside that contained multiple capacitors, which of course, had to be replaced.  I removed each one and rebuilt it with new caps before reinstalling it.  I had a bad volume control which I had to replace.  Luckily, I had a salvaged one that was close in resistance and taper.  The 47 was the only tube I had to replace.  After realigning the IF, it seemed to work very well except for the AGC.  It has none!  I have several sets with no AGC, but I don't listen to them, I just display them.  But, with this set, I wanted to make it an often used one.  The lack of AGC is very annoying, so I played around with adding my own.  I know, never do this, but I was able to come up with a circuit that used only one resistor, one diode and one capacitor.  I will show you how to do this someday.  The circuit worked so well, I left it in the set, at least for now.  Shame on me...

This radio sets in the foyer and is the first thing you see when you enter our house.  It is my favorite radio.



Grunow Model 750
This is a Grunow model 750 also known as the "World Cruiser" from 1937.  The tube compliment consists of 6D6, 6A7, 6F7, 75, 42, 76 and an 80.  It has four bands covering 550 kcs. to 21 mcs. with no gaps.  This is a real performer with the tuned RF amp.

I purchased this one at an old radio swap meet in northern Indiana the spring of 1999.

When I first brought this one home, the cabinet looked pretty bad.  There was veneer missing from the top and grill area.  There was a one-inch chunk of wood gouged out of the top corner.  I am not sure, but the band switch knob might be a replacement.  I stripped the finish completely, replaced the missing veneer and repaired the other damaged wood areas.  My wife repainted the black accents.  Finally, I applied some toner and six coats of clear gloss lacquer.  I was able to save the original grill cloth.

As for the chassis,  I replaced the 6A7 that was very weak, then replaced all of the suspect capacitors and checked resistors for out of tolerance.  After bringing it up on a variac, it was dead.  After a lengthly bout of troubleshooting, I had found an open IF transformer and two open RF coils in the band switch section.  I was able to repair the broken winding on the IF rather easily, however, the band switch coils were another story.  There was what appeared to be corrosion on the coils, possibly from moisture, which had turned patches of the windings into a green mass.  Removing the coils from the band switch was not a job for the faint-hearted.  It was as though the set was built on an assembly line and the band switch was the first part installed with everything else added on around it!  After a lot of work removing the coils, I was able to count the number of turns and rewind them with the same size wire.  After this, it came to life.  All the work on this one had payed off.  The dial tracked very well on all bands and the IF just needed a touch up.  Not only is this a sensitive set but it really has a great sound.  As you can see from the picture, it is a big table set but it fits nicely on my night stand.



AK 55C
Everyone's collection would not be complete without an Atwater Kent.  The is the AK model 55C in a lowboy cabinet.  It is a TRF set from 1929 and has two 24's, two 27's, two 45's and an 80.  Atwater Kent had their consoles built by fine furniture makers such as Red Lion, Kiel and Pooley.  I haven't been able to identify the cabinet maker, so far.  If someone does, please let me know.

I bought this in 1992 from a local antique dealer.  Usually, I don't buy from antique stores, but I couldn't pass this one up.  I just liked the look of it.  It reminded me of a similar set I had dragged home when I was a kid.

This turned out to be one of the most difficult restorations I have been involved in.

The cabinet had water damage from the floor up to the top of the spindle legs.  Part of the wood trim pieces were missing.  The grill cloth was missing and the wood grill was broken with half of it gone as well.  The top looked like it was used to crack walnuts on and one side was faded from, what looked like, sun exposure.


The hardest part was making a new grill.  All I had was half of the original.  I began by tracing an outline of what I had, then flipping it to get a mirror image for the missing half.  With this as a pattern, I cut out a new one from one quarter inch plywood.  I painted the inside edges black and stained the front to match the rest of the cabinet.  Fortunately, there was a scrap of the original grill cloth left on the inside of the cabinet.  I used it to find a reproduction from Antique Radio Grille Cloth Headquarters that matched pretty well.  I made new trim pieces from cross sections of dowel rods and glued them in place.  I was able to restore the legs and sun-faded side by removing all of the old finish then adding a combination of stain and toner to get the original look.  As it turned out, the top was solid wood with no veneer so sanding down the scratches and gouges was no problem.  Again, several coats of lacquer provided the final finish.

The chassis was rather clean on this one with practically no rust.  I have seen other 55C's and they all looked good too.  Atwater Kent was known for their quality of parts.   They could make bakelite parts with such detail that they were amazing for their time.

Upon first checking, I found both 45's to be rather weak and needed to be replaced.  As you know, these are not cheap!  A matched pair of 45's sell for more than what I paid for the whole radio!  I happen to have two NOS GE 45's that I reluctantly installed in it.  After replacing the usual caps and one resistor, I powered it up on my variac just to learn that I needed to do more troubleshooting.  I found one of the RF coils open which was an easy fix but further investigation found a problem which, as it turns out, is common with AK 55's.  The interstage audio coupling transformer was open.  This is a real bear to repair because the transformer is encapsulated in a black tar-like substance within a metal can.  The only thing you can do is carefully remove the unit and heat it in an oven, about 300 degrees for 10 to 15 minutes or until the tar softens enough to pull the mess out of the can.  Once out, I used a heat gun to remove enough tar to find that the transformer was unrepairable.  I should have just discarded it when I got it out.  I found an almost exact replacement for it at Play Things Of Past.  I installed it in the can and packed it with styrofoam peanuts.  At least it won't be a problem to get it open again if it ever fails.  You can remelt the tar and put it back in if you want the ultimate in authenticity but I have heard the potted transformers like these fail because of the sulfur in the tar that corrodes the copper windings.  See links for other sources for a replacement transformer.  If you still can't find one, you might check out what Norman Chamberlain has as a solution by clicking here

This was the last problem other than tightening the metal drive belt on the tuning mechanism.


AK 55C

For a TRF, this set works very well.  Almost as good as a superhet without all the squeals.  The only thing I don't like is the lack of AGC.  As a collector, you must have at least one console in your living room so I chose this one.  Here, you can see it fits in very well with our "old maid" decor (notice the doily on the table.)





RCA B-411
This is a RCA B-411 tube portable radio from 1951.  It has four tubes, 1R5, 1T4, 1S5 and a 3S4.  It operates form one "D" cell and a 67.5 volt "B" battery.  The case is made of a plastic called "Santay" which has a beautiful swirly look.

I have three of these, but this is the only one I have restored.  This was an eBay purchase about seven years ago for $17.  The case was in pretty good shape with no cracks and the dial knob still had the chrome trim intact.  This is a common problem with these.  The metallic backing comes off easily and you will see black splotches in it's place.  The RCA Victor raised logo on the front was originally chromed but is usually worn off on every B-411 you see.  I believe this is caused by rubbing on the leather case.  I have two of the carrying cases with some cracking of the leather on both.

The chassis only needed a cleaning plus I had to replace a 100 mfd. capacitor.  I rebuilt the 67.5 volt battery with seven carbon-zinc nine volt batteries I purchased at Walgreens for 39 cents each.  This, along with a new alkaline "D" cell, brought it to life.

Since these have quick heating filaments, they turn on almost immediately just like a transistor set.  Everyone that first sees this radio thinks it is transistor, especially when they pick it up and turn it on.  They are amazed when I show them the insides!




This is a Raytheon-Belmont Model 7DX21 television from 1948.  It has 18 tubes plus a 7 inch picture tube.  This set was also sold as a kit by Heathkit for a short period.

A good friend gave this set to me.  The cabinet looked pretty good with the usual scratches on top as you would expect on a set this age. 

The chassis was in good shape too, but it needed a lot of work electrically.  First of all, this set doesn't have a power transformer so the tube filaments are wired in series-parallel with a ballast tube dropping part of the voltage.  On most sets like this, the ballast is usually bad.  This one had several sections open.  I was able to dissemble it and replace the "toaster wire" like resistors with conventional power units.  It was tight, but I got them to fit.  I replaced the selenium rectifiers with 1N4007's along with the filter capacitors.  The set was full of old paper and wax capacitors, all of which I decided to replace.  Two of them were 5,000 volt rating which I finally found replacements for on eBay.  I cleaned all of the controls.  Upon checking, about 12 out of the 18 tubes were either weak or not usable.  Since these were inexpensive, I replaced all of the suspect ones.  I had no way to properly check the CRT, so I just hoped it was OK.  When I first powered it up with a variac, I could get a raster and some snow but no picture even when connected to our local cable.  It turns out the turret tuner needed further work.  I had to get inside it and clean the contacts and try to realign the channels.  Slowly, I begin to get a picture.  With further realignment of the IF, I had a decent picture with good sound.  The old CRT was in surprisingly good shape.

On the cabinet, I had to dissemble the front bezel around the CRT and clean under it.  I was able to remove part of the original finish and sand out all of the scratches on the top and sides.  Amazingly, the original decals by the knobs, were still intact.  After the final sanding and going over the cabinet with 0000 steel wool, I applied 4 coats of clear gloss lacquer while using the steel wool between each coat.  I used bee's wax to get the final polished look.

I really like this set, not only for it's looks, but because it's fairly small and lightweight because of the lack of power transformer.


Still under construction, lots more coming soon!



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