A few things you may look at....
Go into service menu & write down all the numbers.
Compare to the manual, some are set to feature level per
model. Others are true adjustments.
Had several Sonys that the tuner/IF assy shorted at the data line.
Gave all sorts of strange symptoms. None of the IC's were getting
data to load up. So check the DATA, CLOCK & ENABLE lines
for clean wave forms. Activity usually in bursts but sometimes
only on key press.
Its not rare for Eproms to go corrupt.
Zeno
