Could be a failing capacitor high in ESR, start by checking electrolytics
with your ESR meter in critical circuit areas like the power supply, scan
derived voltages, etc. Also look for failing connections.

David

John wrote in message
...
Hi, I have a 4 year-old Hitachi C28W511TN widescreen TV. Recently, and
only
75% of the time, when I switch it on, it turns itself off about a minute
later.

Strangely it doesn't make the familiar click and fizz inside the box that
I
hear when I turn it off with the remote, it almost switches the tube off
'silently' (like a PC monitor going into blank screensaver mode) and there
appears to be a brief moment just before it does this when it 'thinks
about
it' as the picture rapidly disappears once, then reappears, then switches
off (I think! - it's all very fast).

When I press ON on the remote, it doesn't 'click' on, the picture just
comes
back silently without a standard 'I'm turning on' click.

It then turns off again 30 seconds later!

I repeat this 2-7 times, then it stays on for the rest of the night until
I
choose to turn it off. It's like it gives up fighting with me and just
stays on, displaying a perfect picture.

It's not an IR issue as when I turn off with IR, I hear a click and fizz
in
the box.

Any ideas? Help much appreciated. I'm tech-savvy and would like to
attempt
a home repair if you can advise a simple part I need to replace.

John