monitor only works on 486
G.B.
2meg video card at 800x600.
On several newer PC's (Pentium 1/II), with various video cards, horizontal
stability is very bad. The image tears and jitters badly when turned on,
getting better when warmed up for 10mins or so, but still has some jitter.
The monitor has no horizontal phase adjustment. It is stable at 640x480 but
who wants to use that low res nowadays.
Anyone have thoughts about this problem, and why it is ok with old 486 PC?
Greg
Valentin Guillen
First thing you might want to do is a bit of web research, either on the
Micron web site or other location. You'd want to find the particular
monitor's Horizontal scanning frequency/frequencies, and the monitor's
vertical refresh rate/s
My thought here is that the 486 is probably using a windoZ version,
because your post headers indicate to me that you're using some nasty
windoz software. More than likely, your ATI Mach32 vlb care is using a
default windoZ video driver, instead of the dedicated ATI video driver
available from the ATI website. This default windoz driver doesn't give
you the opportunity to dictate the use of non-default horizontal scan
rates or non-default vertical refresh rates. Therefore, when using that
video card, your monitor is probably being fed a standard VGA or maybe
even a standart VESA horizontal/vertical rate which is very
non-vergonomical on your eyes, but which is quite stable and doesn't
exhibit any visible flaws.
When using newer video cards with more advanced capabilities, they are
probably feeding your monitor signals of much more advanced
capabilities, (much higher horizontal scan frequencies, along with much
higher vertical refresh rates, which are much more ergonomical and less
harsh on your eyes because they don't produce visible screen flicker)
but your monitor is not capable of correctly accepting and processing
those signals.
Now, don't make the common mistake of equating the screen resolution, to
any particular horizontal/vertical frequency rates. They are entirely
different phenomena. Newer video cards commonly default to more
ergonomical frequency rates with their standard drivers, because it is
commonly assumed at manufacturers that you'll be using the video card
with much newer monitors with much more advanced capabilities.
Be aware that by sending the incorrect frequencies from a video card
into a monitor which is not designed to accept them, that you can
permanently damage your monitor.
Find out what are the correct frequencies for your monitor. Some
monitors can only accept one preset combination. Others can accept two
or three discreet combinations of frequecies, and others can accept
variable ranges of horizontal/vertical frequencies. Be sure you know
what yours accepts. Then, open the display properties dialog box in
control panel and look in advanced settings to see if you're given the
option to select the "refresh rates", ensuring that you don't exceed the
capabilites which you've ascertained for your monitor.....
I suspect that the monitor is quite old, and it is either a straight VGA
monitor or it is a VESA compliant monitor of slightly better
capability. If/when you want to use the monitor with newer computers,
BEFORE using the monitor, be sure to enter the display properties dialog
and lower the refresh rates to some known value which the monitor will
accept. Alternately, forcce the newer computers into "safe mode" to
make the changes to the display settings, and THEN reboot with the newer
settings, and the monitor will work fine with the newer computer/video
card combination.
Good Luck,
Valentin
Valentin Guillen
http://support.micronpc.com/apps/specs.asp?PartNo=MNN001045-00&PartDesc=15+in%2E+Panasonic+500FGX+Monitor+w%2F+Micron+Logo
MNN001045-00
Picture Tube: 15 in. Invar shadow mask, 13.8 in. diagonal viewable
Dot Pitch: 0.28 mm DOT Pitch
Maximum Resolution: 1280 x 1024
Number of Display Colors: Unlimited
Normal Operation: 72.5W
Suspend Mode: 12.2W
Off/Sleep Mode: 3.9W
Horizontal Scanning Frequency: 30-64Khz
Vertical Scanning Frequency: 50-120 Hz
Overall Dimensions (WxHxD): 372 x 381 x412mm
Weight: 13.5kg
Signal Connector Cable: D-Sub type connector
Power Cord: Detachable power cord
Safety: UL, CSA, TUV/GS, DHHS
EMI: FCC Class B, TCO ’92
Emissions: MPR II, CE
Energy Saving: EPA Energy Star, VESA DPMS
Windows 95: VESA DDC 1/2B
FCC ID Number: ACJ92512121
Files and Documentation
Drivers
http://support.micronpc.com/apps/filelist.asp?PartNo=MNN001045-00&PartDesc=15+in%2E+Panasonic+500FGX+Monitor+w%2F+Micron+Logo
Windows 95
Monitor MCRNMON.EXE
http://support.micronpc.com/apps/disclaimer.asp?FilePath=/Support/Desktop/Monitors/Micron/mcrnmon.exe
28KB
8/21/1997
Micron (15 in.)500FGx and (17 in.)700FGx Windows 95 monitor drivers
William R. Walsh
You're probably asking the monitor to do more than it can, but not so much
that the image becomes totally distorted.
Many early "SVGA" displays were able to run 800x600 at a 56Hz vertical scan
rate. Of course, early adapters (like your Mach32) were able to provide this
rate happily.
Most newer video adapters can still provide a 56Hz vertical scan rate in the
hardware, but the drivers frequently don't have this support in them...going
only as far back as 60Hz. However, most early SVGA monitors I've seen could
at least display the 60Hz scan at 800x600 with only a darker picture--not
tearing and disortion of the image. I have a few monitors like this.
If you want to try and get this to work, look at the scan rate selections
available to you from your video card's drivers. Under Windows 98, you can
usually get the display hardware to give you the 56Hz scan rate by selecting
a generic 800x600 monitor (no 75Hz variations) and then choosing the
"default" scan rate from the drop down box in display properties. This
is--of course--a back door solution and it doesn't always work.
Some video cards might also let you program scan rates for various
resolutions, but as I mentioned earlier, only a few cards and drivers allow
56Hz. The better the video card, the better your chances.
William
Franc Zabkar
finger to keyboard and composed:
I have seen and corrected a similar (?) problem on an old AOC monitor.
The problem was that the graphics card did not have enough current
sinking capability on its H & V sync outputs. IIRC, this monitor used
a 74LS86 gate for sync polarity conversion, with an RC combo on each
sync input, as follows:
||\
|----------|| \ XOR
+/- | || \_______ + sync
H or V sync 0--|- R ---|--|| /
| || /
C ||/
|
_|_
=
In those cases where sync is negative, capacitor C is charged to +5V.
When the sync pulse goes low, the graphics card needs to be able to
sink the current demanded by R. IIRC, in my case R was 100 ohms which
means that the current would have been 50mA. This turned out to be too
much for an S3 card, but was OK for a Trident. The "fix" was to
increase the value of R.
-- Franc Zabkar
Please remove one 's' from my address when replying by email.