For those who asked for more information, the "service number"
is SS2712VK9, serial number 091-25500260, manufactured in December
1990, and shows a "module replacement number" 9-896. There is
no information identifiable as a "chassis number" that I can see
anywhere.

Have a Zenith SS2712VK9 with a little problem with horizontal
size stability. The sides of the picture intermittantly move
in and out a bit. Vertical is stable, tuning and sound are
okay, etc. Supplies and horizontal drive signal appear to
be solid and stable. I am suspecting something in the pin
correction circuitry. Anyone have a schematic or tips they
are willing to share? TIA.