CTC-4 Director 21

[Phil Nelson]

Originally Posted by SwizzyMan

If push comes to shove with the IF, I can always inject a composite signal into the grid of the video amp tube.

That's what I had hoped, too, but video injection is not as simple on the CTC-4 as in typical BW sets. The last two sections in the article at https://antiqueradio.org/RCACTC-4ColorTelevision.htm discuss this issue.

Executive summary: video injection requires adding a video preamp as described in the 1956 RCA Broadcast News article. I did breadboard such a preamp, but version 1.0 was disappointing and I set the project aside to work on other stuff for a while.

On the positive side, those are pretty true-looking color bars. You are not far from having a very watchable CTC-4. The edge convergence might never be as good as the center convergence, but that's common in early color roundies. Whichever manual you follow, take Bill's advice -- go step by step in the order shown and do not skip steps.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html