Faint vertical streaks on new monitor
Wizard of Ozz
old computer, with a very old video card, a SiS 6326 (Silicon
Integrated Systems) from 1997. I'm using Windows 98.
I installed the appropriate driver that came with the monitor CD.
I have read the entire FAQ at www.repairfaq.org and my problem didn't
come up.
When I had the display at 800*600 with 75 Hz refresh rate, there was a
linearity problem. The 2 inches closest to the right and left of the
screen were slightly compressed. Barely noticeable by the naked eye.
By measuring the distances using a gif image with evenly spaced lines,
I calculated the difference (from the center screen) to be between
5-10 %. In the FAQ it says that cheap monitors can be expected to have
up to a 2 % difference in linearity (I take this monitor to be on the
cheapo side). But I solved this problem by changing the Hz rate. And
that's where my real problem comes in.
After reading the monitor CD manual to make sure I wasn't doint
something I would regret, I manually changed the refresh rate to 85 Hz
(always at 800*600). Perfect! Beautiful image. Except...
There are these evenly spaced vertical lines, just noticeable, across
the screen. Others might not complain about them. I'm a perfectionist
(there's a bit about perfectionists in the FAQ). There's 7 of them.
They weren't there at 75 Hz. Very evenly spaced, about 4.2 cm apart
(1.65 inches). They are each 1 mm thick (0.04 inches). They seem to be
slightly brighter than the sorrounding picture. On a black image they
don't appear, but on a uniform image of white, red, blue, or green,
they do. When viewing text, I can't notice them, though they still
appear in the blank parts of the text screen. They stretch from top to
bottom. The 2 closest to the left and right side of the screen are
about 2 and 3 cm respectively from the edge of the screen.
If I move the screen using the controls on the side of the monitor,
the lines move with the screen.
The image, otherwise, is absolutely perfect, beautiful, perfect
linearity, colors absolutely perfect, no strange noises, no problem
anywhere whatsoever.
One possible factor I noticed in the FAQ which might apply: most video
cards and monitors use 75 ohms, but older stuff might use 50 ohms, and
this could cause an impedance mismatch. The video card is old, from
1997.
Thanks in advance for any help.
P.S.: one final off topic query while I'm at it. The specifications on
the CD manual said the monitor had presert timing modes for vertical
frequency of 75000 Hz at VESA 640*480, and 85000 Hz at VESA 800*600
and VESA 1024*768. Sorry for the stupid question, but does this mean
the monitor will blow up if I change the desktop screen resolution
from 800*600 to 640*480 without first reducing the refresh rate to 75
Hz? I read in the FAQ that modern monitors automatically block any
signal which is incompatible with their hardwired specs. As I read
this I couldn't help but wonder: what a brilliant tactical move,
allowing your clients to live so they can shop again another day :) !
Pure genius! And it only took them 20 years to think of this! [Irony
off]
Craig Hart
area.
The faults simply mainfest differently at different refresh rates.
Either junk it, or have it professionally fixed.
"Wizard of Ozz" <easytore...@email.com> wrote in message
news:fbcc7457.04102...@posting.google.com...
Jeff Rigby
mfg.) It was the video card. Replacing it fixed the problem. Lines showed
up with different symptoms at different refresh rates. I assumed it was a
cap on the video card. Bad cap in the power supply (powering the video) in
your monitor can cause the same problem. The regularity of the lines you
describe make me think it's the video card not the monitor. vert lines from
left to right should not be the same intensity or as sharp as you travel
across the screen.
"Craig Hart" <ch...@nospam.ta> wrote in message
news:417b...@usenet.per.paradox.net.au...
Sam Goldwasser
> I just bought a Samsung Syncmaster 793s 17" monitor. I'm using a very
> old computer, with a very old video card, a SiS 6326 (Silicon
> Integrated Systems) from 1997. I'm using Windows 98.
You think that's old? :)
> I installed the appropriate driver that came with the monitor CD.
>
> I have read the entire FAQ at www.repairfaq.org and my problem didn't
> come up.
Well, at least one person in the Universe has done so!
> When I had the display at 800*600 with 75 Hz refresh rate, there was a
> linearity problem. The 2 inches closest to the right and left of the
They probably didn't do much to optimze the design for a resolution
and scan rate that no one uses anymore except you. Oops, sorry. ;-)
> screen were slightly compressed. Barely noticeable by the naked eye.
> By measuring the distances using a gif image with evenly spaced lines,
> I calculated the difference (from the center screen) to be between
> 5-10 %. In the FAQ it says that cheap monitors can be expected to have
> up to a 2 % difference in linearity (I take this monitor to be on the
> cheapo side). But I solved this problem by changing the Hz rate. And
> that's where my real problem comes in.
>
> After reading the monitor CD manual to make sure I wasn't doint
> something I would regret, I manually changed the refresh rate to 85 Hz
> (always at 800*600). Perfect! Beautiful image. Except...
>
> There are these evenly spaced vertical lines, just noticeable, across
> the screen. Others might not complain about them. I'm a perfectionist
> (there's a bit about perfectionists in the FAQ). There's 7 of them.
> They weren't there at 75 Hz. Very evenly spaced, about 4.2 cm apart
> (1.65 inches). They are each 1 mm thick (0.04 inches). They seem to be
> slightly brighter than the sorrounding picture. On a black image they
> don't appear, but on a uniform image of white, red, blue, or green,
> they do. When viewing text, I can't notice them, though they still
> appear in the blank parts of the text screen. They stretch from top to
> bottom. The 2 closest to the left and right side of the screen are
> about 2 and 3 cm respectively from the edge of the screen.
>
> If I move the screen using the controls on the side of the monitor,
> the lines move with the screen.
So the lines stay with the picture? Are they aligned perfectly with
the pixels?
> The image, otherwise, is absolutely perfect, beautiful, perfect
> linearity, colors absolutely perfect, no strange noises, no problem
> anywhere whatsoever.
>
> One possible factor I noticed in the FAQ which might apply: most video
> cards and monitors use 75 ohms, but older stuff might use 50 ohms, and
> this could cause an impedance mismatch. The video card is old, from
> 1997.
Not likely. 50 ohms has never been used recent times.
You should check the monitor with another video card or PC as it may indeed
be the video card as someone else suggested. Ignore that guy who didn't
bother to pay attention to what you wrote and said to junk the monitor.
> Thanks in advance for any help.
>
> P.S.: one final off topic query while I'm at it. The specifications on
> the CD manual said the monitor had presert timing modes for vertical
> frequency of 75000 Hz at VESA 640*480, and 85000 Hz at VESA 800*600
> and VESA 1024*768. Sorry for the stupid question, but does this mean
> the monitor will blow up if I change the desktop screen resolution
> from 800*600 to 640*480 without first reducing the refresh rate to 75
> Hz? I read in the FAQ that modern monitors automatically block any
> signal which is incompatible with their hardwired specs. As I read
> this I couldn't help but wonder: what a brilliant tactical move,
> allowing your clients to live so they can shop again another day :) !
> Pure genius! And it only took them 20 years to think of this! [Irony
> off]
Unlikely but no way to know for sure. It really shouldn't blow up.
--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html
Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.
Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the feedback form on the S.E.R FAQ Web sites.
Unlikely but no way to know for sure. It really shouldn't blow up.
Craig Hart
also.
The original poster doesn't say, but implies that he just bought the MONITOR
(not the whole computer); thus I am assuming he had a different monitor
working OK previously.
If this is so, a quick test by swaping back to the original monitor will
verify. Apologies if I've misinterpreted.
"Jeff Rigby" <jf...@comcast.net> wrote in message
news:HM6dnQVgv8K...@comcast.com...
Franc Zabkar
Ozz) put finger to keyboard and composed:
>I just bought a Samsung Syncmaster 793s 17" monitor. I'm using a very
>old computer, with a very old video card, a SiS 6326 (Silicon
>Integrated Systems) from 1997. I'm using Windows 98.
<snip>
>After reading the monitor CD manual to make sure I wasn't doint
>something I would regret, I manually changed the refresh rate to 85 Hz
>(always at 800*600). Perfect! Beautiful image. Except...
>
>There are these evenly spaced vertical lines, just noticeable, across
>the screen. Others might not complain about them. I'm a perfectionist
>(there's a bit about perfectionists in the FAQ). There's 7 of them.
>They weren't there at 75 Hz. Very evenly spaced, about 4.2 cm apart
>(1.65 inches). They are each 1 mm thick (0.04 inches). They seem to be
>slightly brighter than the sorrounding picture. On a black image they
>don't appear, but on a uniform image of white, red, blue, or green,
>they do. When viewing text, I can't notice them, though they still
>appear in the blank parts of the text screen. They stretch from top to
>bottom. The 2 closest to the left and right side of the screen are
>about 2 and 3 cm respectively from the edge of the screen.
>
>If I move the screen using the controls on the side of the monitor,
>the lines move with the screen.
Do the lines move with the raster, or do they move with the video
content? What happens if you display a black screen and max out the
brightness and contrast?
- Franc Zabkar
--
Please remove one 's' from my address when replying by email.
Wizard of Ozz
> easytore...@email.com (Wizard of Ozz) writes:
>
> > If I move the screen using the controls on the side of the monitor,
> > the lines move with the screen.
>
> So the lines stay with the picture? Are they aligned perfectly with
> the pixels?
>
I don't understand perfectly your question, but here goes: if I draw a
vertical line in the screen with photoshop, they will be perfectly
parallel to that line.
> > The image, otherwise, is absolutely perfect, beautiful, perfect
> > linearity, colors absolutely perfect, no strange noises, no problem
> > anywhere whatsoever.
> >
> > One possible factor I noticed in the FAQ which might apply: most video
> > cards and monitors use 75 ohms, but older stuff might use 50 ohms, and
> > this could cause an impedance mismatch. The video card is old, from
> > 1997.
>
> Not likely. 50 ohms has never been used recent times.
>
> You should check the monitor with another video card or PC as it may indeed
> be the video card as someone else suggested. Ignore that guy who didn't
> bother to pay attention to what you wrote and said to junk the monitor.
>
I'm going to hook up the monitor with another computer to see what
happens. Thanks for the help.
Wizard of Ozz
They move with the raster. On a black screen (a black gif image
engulfing the screen) the lines disappear completely. Changing the
brightness or contrast doesn't affect this.
Marlboro
> I just bought a Samsung Syncmaster 793s 17" monitor. I'm using a very
> old computer, with a very old video card, a SiS 6326 (Silicon
> Integrated Systems) from 1997. I'm using Windows 98.
That's 1st problem
>
> I installed the appropriate driver that came with the monitor CD.
>
> I have read the entire FAQ at www.repairfaq.org and my problem didn't
> come up.
>
> up to a 2 % difference in linearity (I take this monitor to be on the
> cheapo side). But I solved this problem by changing the Hz rate. And
That's 2nd problem
> that's where my real problem comes in.
>
> After reading the monitor CD manual to make sure I wasn't doint
> something I would regret, I manually changed the refresh rate to 85 Hz
> (always at 800*600). Perfect! Beautiful image. Except...
>
> There are these evenly spaced vertical lines, just noticeable, across
> the screen. Others might not complain about them. I'm a perfectionist
That's main problem
OH YEAH
news:e3fd5378.04102...@posting.google.com...
Ok, I'm confused....
Is this to say that THIS monitor is no good or just not for this particular
use? I have one just like it with the same problem. Mine is a secondary unit
and I have no use for it otherwise, but other than the faint vertical
streaks as mentioned by the OP in theirs, mine has an otherwise good
picture. Is it worth my while to sell it? IF this monitor is ok to use and
anyone CAN use it, let me know. I'll make you a decent deal.
TRM
Wizard of Ozz
> mfg.) It was the video card. Replacing it fixed the problem. Lines showed
> up with different symptoms at different refresh rates. I assumed it was a
> cap on the video card. Bad cap in the power supply (powering the video) in
> your monitor can cause the same problem. The regularity of the lines you
> describe make me think it's the video card not the monitor. vert lines from
> left to right should not be the same intensity or as sharp as you travel
> across the screen.
>
I connected the monitor to another computer and the lines didn't
appear (did lots of color tests to make sure). So it's the video card,
after all, apparently. Thanks for helping. [I also tested the old
computer with the bad video card by playing a Commodore 64 games
emulator on full screen. This of course changes the screen to some DOS
type view or something. While playing a game on the emulator in this
DOS type screen, the vertical lines don't appear, even on a uniform
colored background.]