CTC-5 Service Info Sought

[bgadow]

Fixing up old tv sets is a constant learning experience and challenge for me. No professional training here, just what I have picked up from years of tinkering, and moreso, what I glean from here and the ARF.

Right now I am working on my CTC-5 (Deluxe chassis) which had a couple issues I had put off fixing. Figured it would be nice to have this one in tip-top shape for the digital switchover. An issue since I got it going: close interaction between the horiz hold/contrast/agc/brightness controls. Any of them can throw the horiz (and sometimes the hv) out of whack. I decided it was time to get serious about this. To start with, my best picture was looking pretty washed out. Tubes, including the crt, are good; I checked hv and it was hovering around 17kv, about 3kv too low by my references. By tweaking the front panel controls I can get a better pic, corresponding with a dead-on 20kv, but it is unstable, tends to jump out of sync or overload.

I have a pretty good library of TV repair books (including color TV) so I dug through them but I haven't found anything that addresses horizontal sweep alignment on these sets. Sams lists a brief set of setup instructions which says to adjust the horiz waveform so that the rounded and sharp points on the waveform are at an equal height, and it shows a picture of the proper wave. (I'm not great with a scope, but am working on it) I can get close but not exact. If I get the 2 peaks even I lose most of the valley; this is at the end of the coils travel and also makes the horiz unstable; it is prone to jumping out of frequency, so much so as to push HOT cathode current way over the line. I have expermented with various combos of waveform/horiz hold position. I would like to read more about this circuit but only the brief write-up in the Sams fits this chassis. Newer books cover the CTC-12/16 well but don't go back and hit the different circuit used here. I actually have some CT-100/21CT55 era stuff but it's no help, either.

Did the factory service manual for this set cover it very well? What might I need to do to correct that waveform? The horiz osc board has been recapped. I had replaced the coil bypass cap with a .015 when it should have been a .01, but have now corrected that. Any advice is appreciated. This set has a lot of potential and I'd really like to see it reach that higher level.