In August of 2011 a Video Karma member posted that he found, what appeared to be, a CTC4 at a thrift shop in Minneapolis; all of the electronics had been gutted so the thrift store people could sell it as a liquor cabinet or a fish tank. The Videokarma member sent me some photos. As it turned out, the cabinet was a full door Cheltenham CTC4 in natural Birch finish; a very rare cabinet. I told him I would like to save the cabinet and he went to the thrift store and purchased it for me for a cost of $40. Shortly thereafter, I drove to Minneapolis and picked up the cabinet.
The cabinet was in surprisingly good condition. This is how it looked when I picked it up. If you look closely you can see water stains in the finish of the top of the set which is caused by iron in the water.
The first order of business was to remove the water stains. I used a slurry of “Bartender’s Friend” cleanser and water and applied a number of applications to the stained areas which slowly removed the gray water stains from the wood.
Next I removed the top of the set and proceeded to refinishing it. I sanded the old lacquer finish until most of the scuff marks were almost gone. Then I applied about 5 coats of Sherwin Williams pre-catalyzed satin finish lacquer, sanding between each coat to level out the areas where the scratches were. Eventually enough lacquer was built up in the scratches to level out the entire surface of the top.
The body of the cabinet was in fairly nice shape. There were a few minor scuff marks that weren’t too deep, so I decided that a recoat of the outside of the cabinet would be sufficient to hide the scuff marks. I masked the set and sprayed the left and right sides. The inside and outside surfaces of the doors were in very nice shape as was the interior of the cabinet around the screen so these areas were left original. Even the original decals for the controls were in perfect condition as this photo shows.
As I stated earlier, this set had been gutted. I received it with only the speakers mounted to the speaker board, and the blonde pencil box . The chassis, picture tube and all associated picture tube mounting components were gutted. This meant that I was going to need a donor chassis, picture tube, and all of the associated picture tube electronics and hardware mounting components. I had two low end CTC4 model 21CT660U Haviland sets. Both of my Haviland sets were about equal in quality But one of them had been re-finished with a fake painted wood grain finish. So because of that, I decided to cannibalize that one as a donor set for the Cheltenham. The Haviland was a perfect set to use as a doner, because it uses the late introduction chassis with all the engineering change orders (ECO’s). Haviland model came to the market at the same time as the Cheltenham and Gainsborough models. All three of these models had the same chassis, so the Haviland chassis was the correct one to use in a Cheltenham model, with the exception of one capacitor value that I had to change in the audio section in order to accommodate the multiple speakers in the Cheltenham.
Now that the cabinet re-finishing was complete, it was time to move on to the re-cap of the chassis. Chassis restoration on this set was very straight forward. As usual I start with the electrolytic cans. This chassis has 5 can capacitors. I have a web page on this web site that shows how I re-stuff electrolytic can capacitors. You can find that page under the “My Methods” section of this web site. The rest of the chassis re-cap was very straight forward. A total of 46 wax paper, 8 tubular electrolytics, 1 mica, and 13 out of tolerance resistors were replaced.
In the past, I have replaced the selenium rectifier stacks with silicon diodes for reliability. The problem with using silicon diodes is that the improved efficiency of the silicon diodes raises the B+ voltages in the set. That in turn requires the installation of high wattage wire wound dropping resistors to bring the B+ voltages back down to the proper level. I have come to the conclusion that the selenium rectifier stacks are fairly reliable, and so on this restoration (and probably all future restorations) I will not be replacing the selenium rectifiers with silicon diodes.
Now it was time for the initial power up. Prior to power up, I tested all the tubes and only found a couple that were weak, so I replaced them with new old stock tubes from my tube inventory. I connected the chassis to my bench test crt unit and then I brought the chassis up to 115 volts using a variac over a period of 30 minutes, slowly increasing the voltage about every 5 minutes.
At around 90 volts things started operating, the high voltage came up and a raster appeared on my test jig. I spent about 2 more hours making adjustments until I had what I considered to be a picture that was good enough to move onto the next phase; final assembly.
Prior to final assembly, I needed to do some work on the polyethylene shroud that fits over the picture tube. The shroud has an external coating of metallic silver on the outside which serves as a conductive surface. The purpose of the conductive surface is to act as a smoothing capacitor for the high voltage. The silver coating is grounded to the chassis and the polyethylene funnel acts as the insulting dielectric between the silver coating and the metal funnel of the crt which is at 25,000 volts. Thus the silver coating is an important part of the electronic functioning of the set. It is rather common for the silver coating on the funnel to be flaking off. So I devised a method of rehabilitating this conductive surface.
The first step is to remove the black silver oxide tarnish that has developed on the silver coating over the past 60 plus years. This is a very stinky procedure so I do it outside on the driveway. To remove the silver oxide, I use Tarnex that I buy at the hardware store. Tarnex is applied to the silver coating using a very soft 2” wide paint brush. I gently paint the Tarnex onto the silver coating. It can take several applications of Tarnex depending on how severe the silver oxidation has become. Between each application I rinse gently with the garden hose. Eventually the silver oxide is removed and you end up with a nice silver gray finish.
The next step is to apply a conductive coating over the old silver surface. I use Aquadag coating that I buy in a spray can. Aquadag is a conductive carbon coating. I mask off the areas that need to be protected, including 1” of the silver coating at the front of the funnel where the purity magnet ring will be located. The purity magnet ring is the source for the ground connection that grounds the metallic silver coating. Then I spray on the Aquadag and I let the coating dry overnight.
The next day I paint the areas which were coated with Aquadag, using aluminum spray paint to simulate the original look of the silver coating. In addition to making the job look more original, the aluminum paint also serves to protect the Aquadag coating which has a tendency to rub off easily.
At this point I was ready for the final assembly. First step was to install the picture tube mounting bezel, safety glass, and brass safety glass trim. I had previously refinished the brass trim. You can see the method I use for refinishing brass by going to the “My Methods” section of this web site.
Then the picture tube, polyethylene insulating shroud, purity ring magnet assembly, deflection yoke, and convergence assembly were installed. And finally the restored chsssis went in. Then final adjustments for purity, geometry, and convergence were made. 12
A word about the knobs. Being a blonde set, the correct knobs are a beige/gray color. The knobs from the Haviland donor set were brown, so I needed to find the correct color knobs. The most difficult to obtain was the UHF channel number indicator. Just by luck I happened to get one of the correct color in a lot of NOS RCA knobs which I had purchased many years ago.
The channel tuning knob was a different story. Fortunately another collector had one of the correct color, however it was in somewhat damaged condition. The throat where the tuner shaft fits into, had been repaired at some time in the past and the repair was poorly done. So I used the outer color part of the knob that he sent to me, and a good inner section from a brown knob and mated the two knob sections together into a single, good, channel selector knob of the correct color. The process involved putting the damaged gray channel selector knob on my lathe and machining out the inside so that all I had left was the gray outer ring. I removed the brown outer color ring from a good knob by sectioning it and removing the brown color ring in pieces. Then I put the 
inner part on the lathe and machined it to the correct size so that the gray color ring would fit correctly. I bonded the inner and outer pieces together with epoxy glue. Even under close examination it's almost impossible to detect that this knob was assembled from two separated donor knobs.
I had a gray brightness knob in my spares. The on/off/volume knob has a solid brass cover that was badly tarnished, so I refinished it. I also had a set of beige/gray knobs in my knob inventory for the controls inside of the pencil box.
And this is what the finished Cheltenham looks like.
The set has good color and an excellent 21AXP22 picture tube. Convergence leaves a lot to be desired which is causing the picture to be less sharp than it should be, but that will have to wait until I have more time to work on it. So here are some screen shots of the completed set. I have to say, from a standpoint of it’s beautiful cabinet, I admire this Cheltenham more than any other set in my collection.
