Any idea about this strange monitor problem?

useradded · 2011-02-01 16:01:25

I don't really know how best to describe this, so bear with me.

Since I bought a new monitor, I have found that after a cold boot (e.g. first thing in the morning) I often have not-quite-flashing jaggedy lines of pixels randomly distributed across the screen, they are usually blue (but sometimes yellow). At first I was rebooting to get the screen back to normal, but more recently I've found that simply switching the monitor off and on again makes them go away.

Some additional information:

# This has occurred with multiple distros.

# The monitor is an NEC Multisync 24WMGX3.

# I have onboard Intel graphics, GMA 4500.

# In preparation for this post I attempted to take a screenshot, but the strange lines did not show up on the picture.

# One of my first thoughts was that there might be a poor connection somewhere between the graphics card and the monitor, but I tried two different DVI cables and the problem didn't go away.

Anybody have any idea what might be causing this?

lagagnon · 2011-02-01 17:36:08

If you have swapped out a different monitor and it did not occur with the other monitor in any situation then it must be a hardware fault in the new monitor.

pataphysician · 2011-02-01 20:48:08

It sounds like a TMDS noise problem, It could be a problem on either the graphics cards TMDS transmitter or the monitors TMDS reciever. Since you've tried two cables, it's probably not due to faulty cable, which can also cause this problem.

If the video card worked fine with other monitors, I would say its likely the monitors TMDS reciever.

Try connecting via VGA D-sub connectors on video card and monitor, this won't use TMDS, see if you still have the problem. If you do then it's probably not TMDS related.

useradded · 2011-02-02 10:23:27

Thanks for the replies, from what I can find googling TMDS noise seems a very likely explanation

Two further questions:

1. Is TMDS noise anything to worry about? That is, is it a sign of deteriorating hardware, or does the noise itself damage the hardware. or is it just an annoyance?

2. Both of the cables I tried were old and of the shitty manufacturer-supplied type, do you think it would make any difference if I tried using the "high-quality, gold plated" kind?

thanks

Last edited by useradded (2011-02-02 10:24:07)

Inxsible · 2011-02-02 15:28:29

Using better quality cable always helps, but I think your monitor is too far down the road to improve upon it. If the cables were manufacturer supplied, then they themselves shouldn't have been the reason to fry your monitor.

Maybe power spikes were to blame. I usually keep my computer/monitor and external hard drive at least behind a good quality surge protector if not a UPS

Inxsible · 2011-02-02 15:47:09

This is what ewaller wanted to write to this thread, but instead reported your post

ewaller wrote:

With high bandwidth systems. cable quality does matter -- but retail cost != Quality. For $DEITY sake, don't buy overpriced designer cables from well known companies with questionable ethics.
Is the noise sensitive to how the cables are routed? Are there any tight bends? Do they pass over something that could be spraying EMI (a power supply, florescent desk lamp) ?
How long is your cable? Are you using an extender cable?
Is it sensitive to ambient temperature? Are you trying to drive the monitor at something besides its native resolution? Are you trying to drive the monitor at something other than its native scan rate? (Most LCDs are 60Hz)

"Report" is NOT the same as "Reply", people !!

ewaller · 2011-02-02 15:57:06

Inxsible wrote:

This is what ewaller wanted to write to this thread, but instead reported your post
...
"Report" is NOT the same as "Reply", people !!

Thank you. I was trying to figure out what happened.
Never done that before.

Inxsible · 2011-02-02 16:37:54

you wouldn't believe how many people use Report and think they have replied to the thread. So no, you are not the only one

pataphysician · 2011-02-02 17:47:28

Your monitor is 1920x1200, so I guess it's possible that if you had a particularly poorly made single-link DVI-D cable, it might be a problem as that is the max resolution it supports. I have used a single-link DVI-D cables for that resolution without problem, so I think it would have to be a very poorly made cable to not work. You could try a dual-link DVI-D cable, if your video card and monitor support it, this has increased bandwidth and better TMDS signal. No need for gold plating, but ferrite beads are good.

IF your certain the problem is not the video cards TMDS transmitter, then I would replace the monitor if it's under warranty, it's a faulty TMDS reciever and it's likely to get worse, and then turning off and on, might no longer fix the problem, and also there could be other problems.

If it's not under warranty, it's probably not going to cause damage to the physical LCD panel, you can always use the analog D-sub with no problems. Also you could try using an HDMI cable, if your video card supports it, depending on how the monitor was manufactored, this might have a seperate TMDS reciever that's not faulty.

Last edited by pataphysician (2011-02-02 18:34:26)

Arch Linux

#1 2011-02-01 16:01:25

Any idea about this strange monitor problem?

#2 2011-02-01 17:36:08

Re: Any idea about this strange monitor problem?

#3 2011-02-01 20:48:08

Re: Any idea about this strange monitor problem?

#4 2011-02-02 10:23:27

Re: Any idea about this strange monitor problem?

#5 2011-02-02 15:28:29

Re: Any idea about this strange monitor problem?

#6 2011-02-02 15:47:09

Re: Any idea about this strange monitor problem?

#7 2011-02-02 15:57:06

Re: Any idea about this strange monitor problem?

#8 2011-02-02 16:37:54

Re: Any idea about this strange monitor problem?

#9 2011-02-02 17:47:28

Re: Any idea about this strange monitor problem?

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