NEC FS-6391- Small pic. when warm.

NEC FS-6391.
Greetings group.
When first turned on the picture fills the screen, but as the set warms
up,
the picture can shrink to a couple of cm in the middle of the screen if
it gets warm enough.

The nearest schematic I have is for a 6390 but I should the a 6391
schematic soon.

Supply voltages seem o.k. and appear to stay the same as the set warms.
Capacitors should improve when they warm up, but I replaced a few
anyway.

Using a hairdrier, the most sensitive area seems to be near IC201
(M52778SP A).

I have tried freeze spray, but nothing I freeze seems to change the
size of the pic.
If the set cools on its own, the picture returns to normal.


Russell Griffiths.