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Keimah Keimah is offline
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Default Help with LCD monitor problem


"Randy Day" wrote in message
...
In article ,
says...

[snip]

It powers up and detects input signals - and goes into standby
when it doesn't receive one - but the screen stays lit up for
only about 2 seconds after power-on. It displays whatever
image
is present when powered on - whether it's the manufacturer's
logo
or a desktop image - and then abruptly goes dark. Even while
it's
lit, the display is rather dim. Not quite hard-to-see dim but
considerably dimmer than normal viewing brightness level. It
seems to be uniform over the whole screen.


You are correct, that is the symptom of a
backlight problem. Whether it's the CCFL
or a cap in the inverter is the question.
If the monitor has dual lamps, they
wouldn't both go bad, so I'd say inverter.


I haven't stripped it down to where I can see the CCFLs
themselves but since there are four 2-pin connectors coming from
the lamps to two inverters, I assume that it has dual lamps. Id
that a reasonable deduction?

The inverter circuits I've seen don't
have too many caps, so, as a first attempt,
I'd suggest replacing them even if they
look ok.


OK. I'll also check the high-voltage coupling ceramic caps for
leakage and nominal values.

You probably don't need to replace every
cap in the power section; the inverter
is usually on its own, away from the other
supplies, since it provides high voltage.

There are what appear to be two independent inverters on the main
power supply board.

Good Luck.


Thanks.