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Computer boots fine - but nothing on monitor

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Soo I bought for $50 the other day a 4U rackmount PC, with a 1GHz P3 and 256MB RAM. Not bad, but I had parts laying around - the mobo/cpu of my "old" (2GHz) computer.

I put the newer mobo/cpu in. The problem is now that when I boot up the PC, I see nothing on the monitor. But I know its booting up fine - I hear the POST beeps, I can hear the beep beeps when I blindly access the BIOS, etc. The monitor though just goes into sleep mode. I dont have an onboard video card... It could be the video card, but Im not too sure. Its def. not the monitor.

Any ideas?

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Is it an ;CD monitor? Try hooking it up to a CRT.

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Boot some CD-based Linux distribution that starts a network service, then try to ping (then ssh into) the unit.

If you can't ping or ssh into it, it's a problem with the BIOS. Otherwise, it's the video card.

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Tis an LCD monitor, but it was designed for VGA (no DVI->VGA.) The lack of output is from the get-go - before the OS boots up. So yeah, I hope to god that it's just the video card and nothing more.

Thanks guys.

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Start simple and small. Is this a dual head or dual DVI card? Are you plugged into the correct port? Is it plugged in firmly? Do you know that the video cable is good?

Are you sure the BIOS is posting? One beep and one beep only is good. If there's more than one beep or the beep is long, that's bad. Check your motherboard manual for a beepcode table or google for it.

I've had a lot of fickle machines (cheap hardware, cheap hardware found in the trash, etc) that need some playing with. Some won't boot if a PCI card is in the wrong place, or a certain IDE drive is plugged in. Another won't boot unless you cycle it a few times, then it'll work great.

Take everything out. I mean everything, you should be left with motherboard, RAM, CPU and video. No PCI, no IDE, no floppy, no nothing. This means taking power from all your hard drives, optical drives and floppy drives as well. At this point, you should be getting video. If you're not, the problem is RAM, video card or power. Probably not CPU or motherboard problems.

If the problem is RAM, try single modules only in different slots. Find a module that works. Some RAM just doesn't want to work in some motherboards and some RAM modules just don't want to work with other modules. It's guess and check to find that out.

If the problem is video, replacing the video card is really the only way to check for that. Booting with no video card should at least produce some interesting beep codes. If you're using PCI video (maybe the same goes for PCIe if this is an SLI board), it often matters which PCI slot the video card goes.

If the problem is power, often taking everything out will fix it. As you add more things back in, it will start to fail, sometimes seemingly at random. If a lot of "random" things are happening, thing you aren't able to reproduce, power is a likely culprit. It can be a difficult problem to diagnose, so if you suspect power try replacing the power supply.

If you exhaust possibilities, the motherboard might be at fault. This is probably the hardest problem to diagnose. Sometimes it's one cold solder joint on one of the DIMM slots. Impossible to diagnose, impossible to see, the only way you know it's there is process of elimination. Some problems are easier to spot. Look for physical damage or bulging caps. I've seen a few boards gouged by screwdrivers, damaging an impossibly thin lead. Burn marks are very bad to say the least.

You have to approach a problem like this experimentally. Sitting down and trying to think it out won't help, you're just going to have to try things until the situation changes.

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Ohm, you're frickin' awesome. :D

The video card was to blame. That means that the other two video cards I got were dead, not a fact that I was particularly looking forward to know (one PCI, one AGP card.) I finally just took the vid card out of my main PC (in the abyss of wires) and it worked just fine. I was able to install Xubuntu just fine.

What you presented though was a great rundown, and I printed it off for future reference. This is a problem, which for various reasons, I've encountered in the past. It's good to have a checklist like that. Thanks!

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I've seen weird video problems. Like a video card that seemed to not work when using DVI but when using a DVI-to-VGA adapter it would work. Sometimes it wasn't the video card but the cables.

My Sun Ultra 1 has a different issue where the default refresh rate of the graphics card is more than my monitors (CRT and LCD) could handle.

Also, the old card might not be bad. Try taking the working card out, clearing the CMOS, then putting the old video card back in. Sometimes, for whatever reason, a system might not realize that the video cards have been switched. ON my home system I have to put in a new video card and let the system sit for 5 minutes unplugged before it "sees" the card. Don't ask em why this happens. I'm guessing that it's a bug in the BIOS but I'm not too sure.

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