On May 2, 12:32*pm, Sjouke Burry
wrote:
saber850 wrote:
On May 2, 3:21 am, "N_Cook" wrote:
saber850 wrote in message

....

Hi,
My LCD desktop monitor has been exhibiting a problem for over 1 year.
It is out of warranty and I would like to fix it.
The problem is that the monitor displays the picture, and then
gradually fades to white, and then gradually fades to black.
The monitor does not exhibit the problem all the time. It comes and
goes. I do not have a procedure which triggers the problem; it seems
to be random. Sometimes it will behave this way for only a few
minutes, while other times it will behave like this for weeks.
I do not do anything to trigger the problem, other than have the
monitor powered on.
I have two of these monitors. I bought both monitors at the same time..
Both monitors are connected to the same video card (nVidia) via a DVI
connection. *Only one of the monitors exhibits the problem--the other
continues to function properly. *When the monitor exhibits the
problem, I can swap the DVI cables and the other monitor continues to
function properly. So I do not believe the problem is my video card or
computer.
I do not know of a method to get the monitor out of this problem
state. I've tried cycling the power to the monitor, and I've tried
rebooting the computer. Neither method fixes the problem. The only
thing I can do is wait for it to fix itself. But eventually, it
malfunctions again.
A video of the problem occurring is available he
http://www.youtube.com/watch?v=W7YpFZVRjcE
Best regards,
Nick
Can you observe discrete jumps in the fade, ie stepped.
Is it a backlight problem? if so perhaps find the brightness control line to
the inverter and break there and add your own subcircuit perhaps. First
monitor that line as maybe a fault inside the inverter chip

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://diverse.4mg.com/index.htm

Thanks for the quick response. *I do not observe discrete jumps in the
fading--it seems very smooth to me.

I do not know if it is a backlight problem; how can I tell?

If it is the backlight, you can still see a picture in strong
ambient light, try different viewing angles and light angles.
If you can still sortof see a picture, it is the backlight.
The slow fade suggests the invertor,or its powersupply circuit.

If it is the invertor or the power supply circuit, would either be
worth repairing/replacing instead of replacing the entire monitor? Is
there any part of an LCD monitor whose expense would not justify its
replacement, and to simply replace the monitor as a whole?