LCD problem, sections of screen dim

[jbclem]

I have a 4 year old 17" Samsung 760V LCD monitor, when the screen is 100% bright it works very well and I'd like to keep it alive. This problem has been occuring for at least a year...when I first turn on the monitor usually the screen is 100% dim, or partially dim. If I keep turning it off and on, eventually the entire screen will be bright and will stay like that as long as it's on.
Occasionally, after a screen saver blankout, it will come back partially dark.

The dark/dim areas vary in position (seem to be horizontal strips), and also dimness (sometimes almost normal bright, sometimes so dim I can barely read text). The monitor is plugged in at a wall socket, not into the computer outlet.

Does this sound more like an inverter board (is this the power supply board?) problem than a backlight problem? Can someone give me some advice on how to troubleshoot this kind of problem. Also, I'd appreciate information on sources of parts for this monitor, they don't seem to be easy to find.

I see this monitor on eBay occasionally, but often is being sold as-is with a dark screen...this must be a common problem with older LCD monitors, or just this particular model?

Regards, jc

 

[Meat Plow]

Subject: LCD problem, sections of screen dim From: "jbclem"
<[email protected]> Newsgroups: sci.electronics.repair
Date: Mon, 13 Nov 2006 13:42:14 -0800

I have a 4 year old 17" Samsung 760V LCD monitor, when the screen is
100% bright it works very well and I'd like to keep it alive. This
problem has been occuring for at least a year...when I first turn on the
monitor usually the screen is 100% dim, or partially dim. If I keep
turning it off and on, eventually the entire screen will be bright and
will stay like that as long as it's on. Occasionally, after a screen
saver blankout, it will come back partially dark.

The dark/dim areas vary in position (seem to be horizontal strips), and
also dimness (sometimes almost normal bright, sometimes so dim I can
barely read text). The monitor is plugged in at a wall socket, not into
the computer outlet.

Does this sound more like an inverter board (is this the power supply
board?) problem than a backlight problem? Can someone give me some
advice on how to troubleshoot this kind of problem. Also, I'd
appreciate information on sources of parts for this monitor, they don't
seem to be easy to find.

I see this monitor on eBay occasionally, but often is being sold as-is
with a dark screen...this must be a common problem with older LCD
monitors, or just this particular model?

Regards, jc

There maybe people will actually read your article now.

Please don't post in HTML and wrap your text at 66 lines.

 

[[email protected]]

jbclem:
I would start by checking the electrolytic capacitors in the
power supply and inverter board sections.
Look especially for capacitors with buldging or expanded tops.
It sounds like a capacitor that is partially healing itself
as it gets warmer.

Hope this helps...
John

 

[James Sweet]

I have a 4 year old 17" Samsung 760V LCD monitor, when the screen
is 100% bright it works very well and I'd like to keep it alive. This
problem has been occuring for at least a year...when I first turn on the
monitor usually the screen is 100% dim, or partially dim. If I keep
turning it off and on, eventually the entire screen will be bright and
will stay like that as long as it's on.
Occasionally, after a screen saver blankout, it will come back partially
dark.

The dark/dim areas vary in position (seem to be horizontal strips), and
also dimness (sometimes almost normal bright, sometimes so dim I can
barely read text). The monitor is plugged in at a wall socket, not into
the computer outlet.

Does this sound more like an inverter board (is this the power supply
board?) problem than a backlight problem? Can someone give me some
advice on how to troubleshoot this kind of problem. Also, I'd
appreciate information on sources of parts for this monitor, they don't
seem to be easy to find.

I see this monitor on eBay occasionally, but often is being sold as-is
with a dark screen...this must be a common problem with older LCD
monitors, or just this particular model?

Regards, jc

If it's the sort of monitor that has multiple CCFL tubes spaced down the
back of the screen then I would first check the inverters, while they're
intermittant would be a good time to attempt repair on them before they
quit completely. It's a lot easier to diagnose if you can make them work
sometimes.