LCD - Bright colour lines alternating with normal colour lines

[Pedrovsk]

Hey everybody,

My monitor is an LG L1732S 17'' 8ms LCD TFT. I've noticed that on all refresh rates (60,70,72,75) there are bright and thin horizontal lines alternating with normal colour ones on about 80% of the monitor (excluding top and right extremities). It reminds me of the old 50hz CRT TVs scanline (difference being it's not black horizontal lines but bright colour lines). Their colour depends on the colours of the normal lines before and after them.

These seem to be more noticeable as I increase the refresh rate from 60 to 75. I've managed to set it to 50Hz with advanced temporization options in my Nvidia drivers "Resolutions and screen refresh rates" and there are absolutely none of these lines with this refresh rate.

The problem though is that obviously there is heavy horizontal tearing with 50Hz and vertical sync caps fps at 50 as well. :(

For you to get a better idea of what I'm talking about here's an example I did on paint (note that it's a very rough example, the lines are a bit more thin):
http://img512.imageshack.us/img512/4219/scanline1rt.jpg

Also I happened to find this still-image from the movie "V for Vendetta" that somehow shows exactly the effect I have on my monitor.:
http://www.metacritic.com/media/film/titles/vforvendetta/picture.jpg



So what do you think the reason is?
Thanks!

[mjc]

What kind of connector are you using?

The standard analog/vga or a digital one?

[Pedrovsk]

This monitor doesn't support digital connector I think. I'm not 100% sure of the VGA/DVI things but I can tell you my monitor has the normal blue conector with pins like this:
http://www.mycableshop.com/PICTURES/vga.jpg

and my graphics card has 2 of these:
http://img60.imageshack.us/img60/541/dvi8sa.jpg
and none of these:
http://img60.imageshack.us/img60/315/analog5fj.jpg

Because of that I need to use an adapter like this one here:
http://images.ldlc.com/photosldlc/00/00/40/24/LD0000402429_2.jpg

Thanks!

[mjc]

Well, since you are going through an adapter already, it is likely to be contributing, if not the cause...

If possible try another cable and/or adapter.

[Pedrovsk]

Thanks. I've just tried 2 different adapters (well, not really different, like the 1st one they both came with the card and are from Club3D) and I have the same problem. I wonder if it's the monitor itself or the use of an adapter.

For this I'll try tomorrow using a different LCD monitor I have upstairs on the older PC (a Samsung Syncmaster 172x) and report back what happens.

By the way this is the area affected on the monitor when on 75Hz (dark red-very noticeable; red - visible; pink - barely visible; white - not affected)
http://img294.imageshack.us/img294/702/monitor5mc.jpg

Thanks again!

[azzey]

I have an LG model similar to that -- the L1730S.

I'm going to make an educated guess and say it's either the video card or monitor (probably the video card... what are you using? That monitor isn't that old to be going already). Let us know if it works fine on another monitor.

[Pedrovsk]

Still haven't got a chance to test the other monitor.

However I've tried connecting this monitor onto my old rig, which was right here since I've upgraded very recently. Its graphics card is an ATI9800XT (not a 7800GT like the recent one) and has both analog and digital entrances so there was no need for adapter.

Nevertheless the "scanline-kinda" effect persists. I think it should be safe to guess that the monitor is partly defective? Or are they supposed to be like this because they're 8ms? (the 12ms Samsung 172x that is on the other PC doesn't show any oddities).

[azzey]

Well... my bet is on the monitor being defective. No monitor should have stupid lines like that. They would never sell it if they all did that.

How old is the monitor? I'd RMA it asap.

[mjc]

I second that motion...

[Pedrovsk]

It's supposed to be brand new (about 3 weeks old). I think I'll return it and buy a different monitor.

Speaking of which, which 8ms LCD monitor would you recommend? Has DVI clear advantages over VGA? Should I go Samsung or keep LG?

Thanks

[azzey]

Personally, I see little or no difference between DVI and VGA inputs. If you buy a DVI monitor, make sure that you have an adaptor for VGA, or that the monitor has to inputs so that you can use it on other computers.

LG vs. Samsung... I guess Samsung is a bigger company (fairly well known). It's mostly up to you. You could also consider ViewSonic (very well known with computer displays) as they tend to be high quality.

When you get the new monitor, let us know which one you chose and what you think of it.