george stringe:
YES, you are probably correct with your diagnosis.
First, check and repair the PS.... could be dry or high esr electrolytics or
defective diode, bridge, regulator semiconductors?
Once you get the PS repaired if you are still having vertical deflection
problems, then check and/or replace the half a dozen or so electrolytics
near and around the vertical output circuitry.
Be certain to check the solder connections near and around the high heat
producing parts.
You might want to go to the website for this newsgroup at
http://www.repairfaq.org/
there, with some search time, you will find a wealth of repair and safety
information.
Good luck with the repair....