Postwar American Television
RCA CTC-5 Restoration
By Dave May
May 12, 2012
I set the chassis up on my Telematic test rig. I did need to make a yoke adapter. This was not a problem. I began the soft start at 50% power and very slowly raised the voltage. My volt meter was tied to the top cap of the horizontal output tube (removed from the tube). At about 60%, I started receiving sound. This confirms the tuner, IF section and audio were working. After I reached full power, I removed the voltmeter and reattached the cap to the hor out. Upon powerup, the high voltage attempted to come up. I then shut things down.
This set wil need a full recap. All paper caps and electrolytics will be replaced. I will restuff the cans if the replacements will fit. Otherwise, I'll gut the cans and hide the replacements underneath. Once I recieve the parts, I can proceed.
May 25, 2012
I completed the recap. There were some issues. The vertical was flatlined. One of the caps I replaced was connected incorrectly. The vertical oscillator tube socket had a broken pin connector. I replaced the socket. That initially did nothing but get that tube to conduct (it wasn't before). After retracing my steps, I discovered the miswired cap. Once I reconnected it, the vertical returned to somewhat normal. The 6BQ5 (vertical output) was very weak. Replacing it got me a nearly full screen. I thought I had a linearity problem. I still don't get full screen. Then, I looked at the print. The yoke's resistance reading on the vertical coils was 60 ohms. The resistance on the rig's is 20. I think this difference is the reason the rig doesn't show full screen.
May 19, 2013
I returned the chassis to the museum and reassembled the set. Upon powerup, I can confirm that there is no issue with the vertical filling the screen (it was from my rig). I began setup with greyscale, convergence and purity.