On 4/23/2015 1:29 PM, Randy Day wrote:
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.

Assuming that your buyer viewed the device on a computer before
purchasing it,
and it was OK,
Something happened in shipping.
A broken backlight is more likely than a bad cap in that scenario.
If one of the backlights is damaged, you'll see the other one light
until the protection circuit shuts off the inverter.


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.

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.

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.

Depending on exactly what you mean by "inverter"...
I've seen more than one where the cap in the supply
to the inverter was the cause. High ESR...overvoltage peaks...
took out one of the fets in the high voltage inverter.

Good Luck.