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I have problems displaying resolutions above 640x480. Until recently the very same computer, graphics card and monitor used to operate just fine. On another computer the monitor still works as expected.

I recently got a new PC, and up until now there has been no problem switching between my old PC and new one with my Dell monitor (and keyboard/mouse/speakers). All the parenthetical items work fine, but my monitor now refuses to display on the old PC unless I boot in VGA mode. Both are running through video cards, but the older PC refuses to display any resolution above 640x480. I can't imagine what could cause this issue - I haven't changed or installed anything since the last time I used this monitor with the older PC. I have been able to switch between the two computers with no problem previously.

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As for my monitor now refuses to display on the old PC -- does it show anything or is it completely blank? Dell has some nice interactive troubleshooting guides for computers; maybe they have the same for monitors. (You're saying that the monitor refuses to do it, but it might also be the computer that refuses it?) – Arjan Nov 15 '09 at 9:12
It works (if you could call it that) at 640x480 resolution when I boot in VGA mode. Any other resolution will not display. When I change resolution to anything higher the monitor craps out. I have no problem displaying very high resolutions with same monitor on the other PC. It could very well be a problem with the PC, but I have never had a problem switching monitors around on different PCs before. Same goes with the monitor. I have changed absolutely nothing about the old PC (a crap dell I picked up for a few $) since the last time I had this monitor connected in the exact same way. – jlingerfelt83 Nov 15 '09 at 9:36
keep the language clean, please! – Molly7244 Nov 15 '09 at 12:16
Reading your "switching between my old PC and new one with my Dell monitor (and keyboard/mouse/speakers). All the parenthetical items work fine" again: you are not using some KVM switch, right? So, you are really unplugging from one computer and then plugging into the other? And what does "the monitor craps out" mean? Blank screen or not? – Arjan Nov 15 '09 at 13:45
I am physically unplugging the monitor and restarting the computer. Yes I mean a blank screen, as if it cannot display the resolution. Sorry about the language, I thought I was keeping it clean by using the C word there, didn't realize things were that strict here. – jlingerfelt83 Nov 16 '09 at 6:36

It sounds like there has been a hardware failure in the video card of the old pc (not the monitor).

Not a catastrophic failure, but some component necessary for generating higher resolution video signals.

Higher resolution implies higher frequencies. It's quite plausible that the failure only affects higher frequencies.

EDIT: I'm thinking of a failure in one of the chips used on the video card. I'm not sure you'd call it 'infant mortality', but I work in the chip-making business and I've seen partial failures like this before.

EDIT2: Chips may have incipient faults which show up at times of stress, such as turning the power on. It seems like a coincidence because, well, coincidences sometimes happen.

When we test devices, we have to check all functions because defects can make some functions fail while others keep working.

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This is possible. There was no excess strain on the card, and it is fairly new - less than a year old in fact. I have had experience with overheating in the past and the old machine showed no signs of it. The card is an 8400 GS Nvidia Geforce if that helps. – jlingerfelt83 Nov 15 '09 at 9:39
I hate to double comment like this, but I should mention that the video card and ram upgrades were installed after the Dell PC was bought - it was used in a bank setting before I acquired it. – jlingerfelt83 Nov 15 '09 at 9:51
A new video card can still fail. – harrymc Nov 15 '09 at 9:58
Good point. It may have. I have only had one video card fail on me so far, and that was due to overheating. If this one failed on me then it had to happen at some point during my last (low quality) gaming session, exiting the game, shutting down the system, then starting it up today. – jlingerfelt83 Nov 15 '09 at 10:01
Response to edits - Good explanation, and probably right. I am in the process of switching everything over to my new PC, hoping to cannibalize the parts of the old for my girlfriend's PC - not like she needs a video card anyway. Meanwhile does anyone else have a possible explanation? – jlingerfelt83 Nov 15 '09 at 10:15

Maybe the higher resolution video modes are set to too high a frequency?

A relatively new video card like the 8400 could easily send 1280x768 at over 100hz for example, and old crt's may not be able to handle that. VGA mode is 640x480 60hz, try keeping the refresh rate at 60hz as you increase the resolution.

Edit: Obviously you should only keep the refresh rate at 60 hz as a troubleshooting measure, if you discover that it works, then you should increase the refresh rate to a more comfortable level.

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As far as I understand it's the same graphics card with the same monitor that used to operate just fine, until some day the monitor was connected to some other system. – Arjan Nov 15 '09 at 13:24
Yes, Arjan is correct. There was no change in frequency or resolution between it working to blank screen. – jlingerfelt83 Nov 16 '09 at 6:38

I truly doubt this is the case (and most often, this requires some human intervention), but: any chance your new computer somehow (and erroneously) updated the EDID in the monitor? Or: any chance the Display Data Channel (required for EDID) is broken in the cable or connector? (You're not using a KVM switch, right?)

Some monitors come with wrong factory EDID information, which then basically prevents one from selecting some resolutions or frequencies in the OS's display settings. For most systems these are just annoyances, and fixing the EDID then merely makes workarounds like "show incompatible video modes" no longer necessary.

In your case, you can in fact still select the very same resolutions that used to work just fine. But maybe the OS now thinks that this resolution allows for a higher frequency, or for non-interlaced operation while the monitor in fact does not support that?

Maybe software like Monitor Asset Manager 2.3 can provide some information? That will show you both the information provided by EDID, and the information that Windows has stored in its registry. If those are different, then maybe you can do a "detect monitor" or "detect screen" on your old computer? (For the sake of troubleshooting, I would first copy the information from that software before running any monitor detection again.)

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Thank you for the answer. My gut reaction had been that the new PC had changed something about the monitor, but I had no idea about EDID information and rejected that idea. I'll run the utility and see what I can find out. – jlingerfelt83 Nov 16 '09 at 6:40

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