DIYbanter - HELP! My EX took everything but my TV and now it's screwing me too!!!

Okay,

I have a Sony KV36XBR200 WEGA (1999 model) that's been a great TV
until a few weeks ago when the picture began flashing on and off every
few seconds. There is no identifiable "blink code." When I turn on the
TV, I've seen the LED flash anywhere from 11 to 18 times before the
picture comes on. Until the set warms up, the picture blinks on and
off continuously. But it gets better as it stays on longer...

I called a repair shop and they came out to look at it. I spent $135
for nothing. The dweeb was mucking around in service mode with the
GCUT setting (turned it to 0) and the picture stopped flashing. So he
concluded that must be the problem and "that'll be $135 please." Well,
he also said that it must be a weak CRT and it would need to be
replaced (estimate was $1400!). Anyway, I called them back when I
discovered that it had nothing to do with GCUT at all. It was just
that the TV warmed up to where it wanted to be and happened to stop
flashing while he was looking at GCUT. So they're going to come back
out to reset GCUT and give me some green back at least. But that's not
going to solve the flashing problem!

Could it really be a weak tube? If so, is there anything I can do to
extend its life a little while (I'm still recovering from the expenses
of the marriage going south). I read somewhere that turning the screen
voltage up might solve the problem temporarily. If the tube is shot,
then that may at least buy me some time. But, I am wondering if
something else may be causing this that could save me a lot of money
on a new TV.

Any advice or helpful tips anyone can give would be appreciated. I
have the back cover off of it, but have no idea how to adjust screen
voltage if that is recommended (and I'm not about to pay the same guy
to do it. I figure he should have done it when he was here last time-
or at least known more than he apparantly does).

Thanks!