5-1-2003 I picked up the CT-100 last Thursday and have been working on it every since I got back on Friday. It was with the 81-year-old original owner and had been sitting in his store window for 40 years. It was in St Joseph KS. This so far is a very good news story. I was whining about the poor condition of the finish until I started reading about the hard luck cases on the Internet. I pulled the chassis and picture tube for the trip and the tube rode on the passenger seat next to me.
The picture tube was said to be good when the set quit 40-years ago. The getters are full and shiny. The guy included some books and two were devoted to the 15GP22. The book noted the guns are identical to the 5TP4, so I used my tester with an adapter I made that brings the leads out to pin contacts. I plugged the contacts in the respective pins, and all three guns tested full-scale in the green with no leakage between elements. The chassis is complete and looks as though it was never worked on -- no rust and pretty bright all over. All tubes tested as new and are all RCA white label. I am in the process of reforming the electrolytics now. I found a blown fuse in the LV section and I'm sure that's what took it down. The transformer is good and so are the selenium rectifiers. I checked the peakers and found four duds. I ordered a full set of molded inductors from Nebraska Surplus as well as a set of axial electrolytics at very reasonable prices. The set is 100 percent complete.
Here's the bad news and its not all that bad. The cabinet was about 70 percent free of paint. Its as though someone took stripper to it on one side, the front, and the top. This was due to sun damage, which also faded the grill to near white. So, I will be refinishing the cabinet and replacing the grill. The channel sector lens is a bit yellow but is usable. I am taking lots of pictures and will send some soon. The large plastic bezel has a small defect at the bottom of the screen. It looks as though it was heated, which resulted in it sagging. Something put pressure on it, as it left a mark right on the edge. It’s not too bad, and with all the junk sets, I might be able to find a defect-free replacement. I will keep you posted as things progress.
5-22-03 After completing the chassis restoration replacing 24 out-of-tolerance resistors, three FP electrolytics, 12 axial electrolytics and 65 paper caps, the chassis powered up with no initial problems.
However, after about an hour of run-time, a leak developed between the secondary and primary of the Vertical Convergence Output Transformer (T12 Sams). This was pulling down the focus rectifier to about 1.5 kV. I have unpotted and disassembled this transformer and have detailed the construction, which I will provide after winding a replacement.
THE PRIMARY. It consists of 2355 turns of #40 ga. in eight layers. The insulator that isolated the primary from the 4.5 kV on the secondary consists of two wraps of 15 mil laminated celluloid plastic.
I found the insulator to be distorted due to shrinkage, and a few cracks had developed. Two small punctures were found where the second layer had cracked underneath it. In the photo, the punctures can be seen at the tip of the Exacto knife.
At any rate, I am collecting the materials to wind a new coil and will allot a month or so to get it done. Now that I know how this transformer is constructed, I believe others can be repaired without a complete rewind.
For example: the primary, which came out quite easily, is closest to the core. You can unwind the primary from inside out. A new primary can then be wound and inserted inside the secondary. New modern materials would make the fit possible because they are thinner and have greater dielectric strength. This method would only work if the secondary coil were not damaged or open.
THE SECONDARY. I removed 6 layers of windings on the secondary to get the construction understood. The secondary has 20,625 turns of #42 ga. with a tap at layer 22 and then 53 layers after that. Each layer in the secondary has 275 turns.