As far as repairs go you need a block diagram & schematic at the least.
The block will show you the paths for all the different inputs. The OSD
looks good & thats a helpful start. We sold Sony & never had problems like this
until flat screens & HDTV. I would bet there is a SMD cap bad but they are
full of them & if one is bad usually others are near that. Its like a
high end car. Get rid of it near the end of a warranty or it will cost
you kilobucks every year.
73 Zeno
LFOD !