Zenith 25DC56 CC- no color sync

[DavGoodlin]

This chassis uses two color dura-modules, as Zenith dubbed the 9-37 and 9-27. The 9-37 has bandpass amp IC, and a demodulator IC. I swapped this with a PTS rebuilt with no effect on the sync issue.

Looking at the 9-27, a crystal and 221-42 IC were swapped out along with a spare module and sometimes you could lock in but the tint control did not work though flesh tones were close, a tad pink.

If the burst from the 9-37 module (bandpass-chroma amps) is missing, would this also present like a missing flyback pulse, which is not the case here?

Most all voltages are close to schematic values.
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