View Full Version : CTC-4 Chroma Alignment


miniman82
02-13-2011, 09:22 PM
I'm now at the point where I need to make sure the chroma section is in order, but I can't find any service info on how to get it done. I do have CTC-9 stuff from Sams, but the circuitry in the 4 is vastly different. Can I assume that I make the same kinds of tweaks to this one, same as the later chassis? Zero beating the local oscilator is an easy one, it's all the other transformers I won't be able to get right without some pointers.

For example, on the 9 it has me tweaking the local oscilator trans for max deflection on a DMM, so I assume the same is done for the driver trans (T115) on the 4? T115 seems to have a lot to do with the phase angle seen by the demods (big change in color bars), so do I just tweak for correct bars with the color and hue controls at center?

What about the band pass and demod driver transformers?

ctc17
02-13-2011, 09:40 PM
The bandpass is the tough part, without directions on what to bias where and how its going to be tough. Leave the bandpass alone unless you have clear instructions. That includes the 4.5 trap, it seriously effects the chroma bandpass.

The rest you can pretty much setup by eye.
Ground out the color afc signal so the afc is not controlling the oscillator, adjust the osc coil for the slowest moving rainbow. (zero beat) When you do that I recommend you use your daily programming source and not some old color bar generator.
Then center the tint and adjust the phase coil for the correct color bars.

bgadow
02-13-2011, 10:20 PM
If you want a copy of the Sams, send me a PM.

miniman82
02-13-2011, 10:44 PM
PM sent!