Hi; I'd almost bet this is another dried-up electrolytic, I just can't seem to find it! The perpetrator is an HP 98751a, aka Sony GDM-1952, (aka Rasterops 19, Supermac etc), and it is a 5-BNC RGB fixed-frequency monitor that does 1024x768 INTERLACED only. Given that, it has been a great display anyway and I'd hate to throw it out.
Problem started a few weeks ago at turn-on. The screen seemed to be traced fully and normally by one field, while the other scrunched up away from the bottom-- so that I had two mouse-pointers spaced about an inch apart when at the lower half of the screen, but moving the mouse up the screen, the pointer images melded back together. As the monitor warmed, the scrunched field stretched back to normal over about 5 minutes. I operated it "as-is" a couple of weeks, just waiting for it to settle out.
Well, it is worse now-- the whole lowest quarter of the screen is affected, and no getting back to normal after even 30 minutes of on-time. I downloaded a zip of .pcx files of the GDM-1952 Service manual, which has the schemata but they neglected to scan in usual boilerplate like Theory of Operation or anything. So I'm guessing what I need to look for. But I am not seeing electrolytics in area which might affect one field but not the other!
Has anyone else battled this symptom? Am I making stupid assumptions or have I missed something? My current web method of posting does not allow me to send a file along, but for those who already have access to the schematics, I am suspicious of C1, C2, and C8 (in the SyncSep/PulseGen section). My reasons for looking at these are: 1) they are electrolytic; and 2) they are roughly around an area that looks like it might have something to say about one fields vertical as opposed to anothers. But I may be all wet.
TIA-- Glynn.