Only "red" color partially broken on LCD Monitor?

[Al Fei]

I searched around and didn't see a problem like this one described.

The colors on my Norwood 17" LCD monitor started looking strange and
when I ran the "Color Gradients" test of the CHECKMON program (which I
got at http://www.benchmarkhq.ru/english.html?/be_monitor.html) it was
obvious that there was a problem with just the color RED (and colors
made up of combinations with RED). The BLUE and GREEN colors were
perfect! It's as if the monitor was having trouble showing more than 8
shades of red correctly when it should handle 256. After the top 3
rows, instead of a smooth, increasingly fine gradient from dark to
light, there are just 3 main bands/shades of red color and the
boundaries between the bands are "jittery". I tested the monitor on a
completely different PC - same result so it's definitely the monitor.


When displaying the desktop or most anything but pictures, the problem
is hardly noticeable but most pictures show annoying and strange color
splotches. They say the most expensive part of lcd monitors is the
glass and the glass seems fine so I'm up for trying a repair, but is
it a bad cap? A bad circuit board or IC? Any ideas?

 

[Sam Goldwasser]

I searched around and didn't see a problem like this one described.

The colors on my Norwood 17" LCD monitor started looking strange and
when I ran the "Color Gradients" test of the CHECKMON program (which I
got at http://www.benchmarkhq.ru/english.html?/be_monitor.html) it was
obvious that there was a problem with just the color RED (and colors
made up of combinations with RED). The BLUE and GREEN colors were
perfect! It's as if the monitor was having trouble showing more than 8
shades of red correctly when it should handle 256. After the top 3
rows, instead of a smooth, increasingly fine gradient from dark to
light, there are just 3 main bands/shades of red color and the
boundaries between the bands are "jittery". I tested the monitor on a
completely different PC - same result so it's definitely the monitor.

When displaying the desktop or most anything but pictures, the problem
is hardly noticeable but most pictures show annoying and strange color
splotches. They say the most expensive part of lcd monitors is the
glass and the glass seems fine so I'm up for trying a repair, but is
it a bad cap? A bad circuit board or IC? Any ideas?

Try the LCD monitor on another PC and/or try another monitor on this PC.

The problem could be in your video card or how its color pallette/lookup
tables are set up.

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[Al Fei]

Try the LCD monitor on another PC and/or try another monitor on this PC.

The problem could be in your video card or how its color pallette/lookup
tables are set up.

I've tried both and it's definitely a problem in the monitor.

 

[JW]

I searched around and didn't see a problem like this one described.

The colors on my Norwood 17" LCD monitor started looking strange and
when I ran the "Color Gradients" test of the CHECKMON program (which I
got at http://www.benchmarkhq.ru/english.html?/be_monitor.html) it was
obvious that there was a problem with just the color RED (and colors
made up of combinations with RED). The BLUE and GREEN colors were
perfect! It's as if the monitor was having trouble showing more than 8
shades of red correctly when it should handle 256. After the top 3
rows, instead of a smooth, increasingly fine gradient from dark to
light, there are just 3 main bands/shades of red color and the
boundaries between the bands are "jittery". I tested the monitor on a
completely different PC - same result so it's definitely the monitor.

Are you sure what you are seeing as red is actually red?
On a totally red display, is there any red at all, or is it black?

When displaying the desktop or most anything but pictures, the problem
is hardly noticeable but most pictures show annoying and strange color
splotches. They say the most expensive part of lcd monitors is the
glass and the glass seems fine so I'm up for trying a repair, but is
it a bad cap? A bad circuit board or IC? Any ideas?

With a DVM, verify continuity of pin 1 on the VGA cable, making sure it
gets all the way to the LCD controller board.

 

[Al Fei]

Are you sure what you are seeing as red is actually red?
On a totally red display, is there any red at all, or is it black?

CHECKMON also has a "Solid Colors" test - red is red and
black is black. No problems apparent with this test at all.

With a DVM, verify continuity of pin 1 on the VGA cable, making sure it
gets all the way to the LCD controller board.

I used different cables on different PCs with the same result.
I suppose there could still be a pin 1 break between the jack on the
monitor and the electronics inside the monitor but I think that would
show more obvious symptoms, not the ones I've described.

 

[Al Fei]

It looked pretty grim for a while. The "green" color started
to go just like the red, and then pure black screens started
having a greenish tinge. I opened up the monitor (it was
tricky figuring out how to do that without damaging the
case too much) and nothing looked burnt / broken so I
ended up buying a new one and using this one with a
"spare" pc. Today, it wouldn't even hold the sync for a
viewable picture! So what did I have to lose? I opened
it up again to do a more complete disassembly and found
the wire bundle from the logic board to the glass was
connected through a special plug/jack that was held
together with 2 dabs of glue. Masking tape was also
used to hold/stableize the cable to the back of the glass
near the connector. The plug had started to unseat a bit
on one side so I re-seated it. That was just part of a more
thorough inspection of the cards, caps, etc. so I didn't
think much of it. I still couldn't find anything that looked
really wrong. But lo, on the first retest EVERTHING
WORKED PERFECTLY!

The way the mounting was, the plug/cable plugged UP
into the jack and despite the glue and tape, the plug
had apparently worked it's way loose over time due to
gravity and movement.