Zenith SC2569 Height Adjust

[Tomcomm]

My Zenith SC2569 has a great picture when running of NTSC dvd inputs but produces a greatly excessive height off my ATSC to NTSC converter box. I've search for the height adjust but there seems to be none! Since I have no schematic I have no way to get into the vertical circuitry and make some haywire modifications. Has any member run into this problem or even have a schematic? Thanks for any help..........Tom