CTC-4 Director 21

[Electronic M]

Have you checked the tubes recently for Heater-Cathode/Heater-anything shorts...That could be introducing your hum bar.

On my set I had to adjust one of the transformers in the color demodulator....The one that controls the phase angles that the 2 demods operate on....It has an above chassis and a below chassis adjustment on it's can...You have to adjust both at once with color bars on screen, and you have to use 2 plastic flat edge alignment tools (metal screw drivers will make your adjustments shift as soon as you remove the drivers from the can)....I had to make my 'alignment tools' out of ruined mechanical pencils. I wish I could tell you which can it is, but it has been ~4 years since I did that work.
http://videokarma.org/showthread.php...Seville&page=4