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Old 04-28-2014, 11:35 AM
DaveWM DaveWM is offline
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Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
agree with others, get the line straight 1st, AGC/filter caps etc...

shifting hues with scene changes... hmmm sounds like a defect in the burst signal to 3.58 mhz osc. the burst signal is used to lock the phase of the color osc (in some sets like GE's and other lower end sets the burst IS the signal that is used to demod the color). try tweeking the horz hold a bit when you see this happens. the burst is keyed by a horz pulse to only sample the video signal at the time the burst is transmitted. the pulse comes from the flyback.

This is not a fix just something to look for. I would recommend looking at tubes in the burst amp and any kind of phase detector in the chroma circuit. Also you should sub in a new 3.58 osc tube. You can also check the 3.58 osc is reactance coil is set, this is covered in the sams, you ground out the burst amp correcting voltage at the grid of the AFC tube and set the reactance coil so the resulting color bars do not move. this gets the 3.58 osc close to the correct setting. This is generally is done when you cant get a color lock, but it would not hurt to check it out, do not go crazy here if any adj is needed it will not be much. The fact that the color is working at all means it is at least within pull in range of the phase detector circuit.

the horz lines on the right are controlled by coils, they have peaks and operate over a fairly narrow range. IIRC they should be set 1st before the Left horz lines (done with pots). the main thing is to see if all the pots and coils do something. I had a issue with a CTC-7 that was from an open coil on the convergence board. Not saying this is your problem, but sometimes things don't work and all the tweeking in the world will not fix it.

http://www.youtube.com/watch?v=2wYn3xLrZj0

Last edited by DaveWM; 04-28-2014 at 12:01 PM.
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