Does it vary with different resolutions/refresh rates?

It seems to be a little more pronounced at lower resolutions (640x480 & 800x600) and not very noticeable at all at 1600x1200 (although I don't really use that resolution outside of games because the text is too small). I imagine that the lower resolutions have higher refresh rates.

Impedance mismatch would be my first guess. Try a different VGA cable and graphics card. See if termination is set to 75 ohm (if there's a switch for it).

boxpressed wrote:

I imagine that the lower resolutions have higher refresh rates.

Usually not, unless you explicitly set it to a higher rate. Windows likes to default to 60 and EDID is almost always sub-optimal.

The VGA cable is attached to the monitor, unfortunately. Unless I'm doing something wrong, 98SE allows me only to select "Optimal" and "Adapter Default" for refresh rates. Both look the same.

You can usually find the current scan rates in the monitor's OSD menu.

Also try re-inserting the VGA cable a few times, and wiggle it around a bit, just to rule out dirty/oxidized contacts. Always rule out simple things first 😀

I see what you mean. Yes, the problem occurs at different refresh rates, as reported by the monitor's OSD. I sprayed some contact cleaner on the the connector after the problem first developed but no change. May try Deoxit.

http://www.repairfaq.org/sam/monfaq.htm#mongslrbda
This suggests dark horizontal streaks could be caused by dried capacitors, either in the video amp circuit or the power supply.

I had a Macintosh SE whose monitor suffered from this same problem. I do believe that bad capacitors were the problem in that case, and they might very well be the problem here.

As many have said, capacitors...

Or your cable is not getting on with it for some reason as that is exactly the same thing that happens when I use my 3 meter cable... An unfortunate limitation of the universe's laws of physics as I cannot place every machine within reach of the workstation, meaning I need the long cabnle. I hate that cable. So, yeah, if you have another cable try it out before you go nuts with the soldering iron.

You could always try to hide the back and tell everyone it is a passive matrix LCD. 😜

I was afraid the problem might be something like bad caps. I'm not handy with a soldering iron, so I'll probably just recycle it if it gets to be too much of a problem. Because I mainly use Windows just to launch games, and because DOS-level graphics/text look normal, I can probably live with it until it worsens dramatically.

It does indeed remind me of a passive-matrix LCD (although nowhere near as bad). I used to have a Toshiba laptop with one of those terrible screens.

whenever i had this issue it was related to too high resolution for the used vga cable (bad shielding, cable too long, ...).
but as your issue persists even at low resolutions, i don't think that it would work better with another cable.

Got ghosting similar to this when I used a very cheap extension cable. Replaced it by one that was bigger and shielded, and problem mostly vanished.

If the cable is attached with the monitor, maybe the monitor can be opened and the cable replaced.