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+1 Horiz osc is way off frequency. This is almost entirely contained on 9-57 Horiz Board, with the exception of the horiz osc coil/hold control and the attached capacitor that forms the circuit that determines the osc frequency.
+1 on the Q803 121-755 Horiz Driver transistor not being the cause. ECG 190 is a closer substitute.
The question is, can the osc run on frequency or is the AFC driving it off frequency.
Do you have a spare 9-57 Board?
Is the plastic stop still in place on the horiz hold control? Has it already been forced past the stop?
Have you replaced any other components on the 9-57 Board?
Re-examine and tighten pins and connectors A11, U4, T13, that connect to the coil.
Common problems:
R808 330ohm 1/2w replace and upgrade to 1w
R821 2.2k 1w replace and upgrade to 2w
Lead sockets for the transistors are always problematic, most people will either remove the pins and solder the xsistor directly to the board, or solder the leads in the pins. Every rebuilt board I've ever seen, Zenith or PTS, soldered the leads into the sockets.
From there you need to troubleshoot the board. At least its not intermittant anymore?
On the Video Proc IC, I've had luck gently scraping with an Exacto knife, also taking a small piece of green scotchbright soaked in DeoxIT or CRC Cleaner, held with a needlenose and gently scrubing. Be care not to over manipulate the pins.
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Beam_T
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