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Old 11-20-2011, 04:41 PM
DaveWM DaveWM is offline
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Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
CTC-15 line pairing

another roundie that I am fighting line pairing with. same deal as the others but this one I cant even find a sweet spot on the vert hold that will let me dial it out. I have several sets that use the RCA multivibrator vert (6GF7) some are fine some have the line pairing issue.

I am going to start with a few tube swaps, the sync sep and the 6GF7, but exp tells me that is not going to do it.

Next up will be to scope the plate voltage (comes from boost) and see if I can see any excessive vert noise. I know there is a big capacitor on the sweep board that should be filtering that out.

scope around the grid of the multivibrator and see if I can see any hash there.

last time I fought this I ended up replacing EVERY cap on the vert circuit. and the intergrater, Kinda fixed it on another set.

The only thing I never replaced was the VDR from the plate of the multivibrator, but I just assumed that was to regulate the feedback pulse to a consistant voltage.
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