Not sure what the root issue(s) were with the problems I had. As noted above first there was an issue with the color amp signal which occurred as I adjusted the Heathkit IG-5240 pocket signal generator, I fiddled with the controls which maybe was my problems.
From there after pulling and putting the chassis back in the issues changed to diagonal lines of signal against a white screen and then later a bright but faint image. The IF and color amp signals now looked correct so I poked around in the AGC and video circuit, all parts in these circuits measured ok. The Zenith Color TV Service Manual by R.L. Goodman has a section on actual issues and resolutions. One issue noted:
Washed-out picture, no sync. AGC, sync trouble. Set may have to warm up before picture fades out. The cause was a leaky or shorted .01uf capacitor at grid, pin 5 of the sync - AGC tube. The capacitor tested ok but regardless I replaced it, was this the issue, I don't know but the set is back working.
Back to the alignment:
Quote:
Originally Posted by old_tv_nut
Question: when you changed output to IF, did you need to adjust sweep width/centering to get the chroma bandpass curve centered on the scope?
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I did not need to change the sweep width/centering. The only change needed is with the signal output and scope vertical settings to get the response curve to show well on the scope screen. The Zenith Service manual does not show what the curve response should look like when feeding the sweep generator through the tuner and IF sections but I assume it looks good. I still get a lower response for the 3.08mc marker when connecting at C1, maybe this is an artifact of the test equipment? Note when connected at the tuner adjusting L17 does a nice job of balancing the 3.08mc and 4.08mc markers, I assume they should have an even response.
