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No display due to motherboard?
July 28, 2011 6:16 AM   Subscribe

Do I really have to replace the motherboard? My computer is showing no display and I think I've ruled out everything except the motherboard. Changing that is obviously expensive and time-consuming, so please tell me if I'm missing anything!

My PC has no display at all, even when booting. There is also a slightly odd POST beep on startup of one long beep and two short beeps.

However, the hard disk lights suggest a normal boot sequence and if I type my password blind, it appears to log in normally, again judging by HDD activity. It seems only the display is not working.

Here's what I've done to narrow down the problem:
  1. I have plugged another computer into the monitor, which displayed fine.
  2. I have connected the computer to the monitor using the VGA socket instead of the usual DVI. It didn't change anything.
  3. I borrowed a graphics card from a friend and tried to use it. No change.
  4. I took the graphics card out and pressed it back in as firmly as I could. No change.
  5. I tried booting with each one of my two memory sticks. No change.
The only other thing I have left to try is to disconnect all USB/SATA devices and try to boot without them. Let's assume that doesn't help.

Is there anything left to do but replace the motherboard? Obviously I don't want to do that unless I'm 100% sure that it is the problem. The idea of buying a new board, dismantling the PC, moving the CPU from the old to the new board and then discovering the problem lies elsewhere causes me anguish.

My PC is home-built and has run without problems for more than two years. The motherboard is a Gigabyte GA-P35-DS3L and the graphics card is a GeForce 7300GT.


Background: Recently I had an hour of PC display problems. My display would freeze for a few seconds, then blank, then return to normal for a while. If I was scrolling when it froze, there would be some distortion on the screen. I reduced Windows hardware acceleration to the minimum, which helped. I installed the latest video drivers, but still was unable to use hardware acceleration. The next day, the problems above started.
posted by Busy Old Fool to Computers & Internet (12 answers total)
 
Sure sounds like the motherboard. But if you've got a spare power supply to test with I'd do that before replacing the motherboard.
posted by 6550 at 6:41 AM on July 28, 2011


Is there any reason to believe you may have CPU damage (OC'd?) It's a long shot but its a variable you haven't tested.
posted by blargerz at 6:44 AM on July 28, 2011


Check your motherboard manual. POST beeps are actually indicative of hardware problems, and the type of signal can tell you what it is. In your case, this means "monitor or graphics card error." Which, given the other things you've tried, means that your graphics card slot is probably hosed.

The last thing I'd check is taking your card and using it in another motherboard. It's possible that both the card and the board are fried.
posted by valkyryn at 6:45 AM on July 28, 2011 [1 favorite]


Could be a leg of the power supply and a little easier to check. I've also had bad fans presumably trigger safeguards to the power supply which may be disabling part of your board. Another quick and cheap check is replacing the CMOS battery on the motherboard, although that doesn't sound like your problem here, a bad battery sometimes causes strange things to happen.

You could also try unplugging every component you can (hard drives, DVD, network cards, fans) to see if that helps. If you have more than one memory module take all but one out and rotate them.
posted by Yorrick at 6:47 AM on July 28, 2011


Thanks for the answers so far.

Sure sounds like the motherboard. But if you've got a spare power supply to test with I'd do that before replacing the motherboard.

I don't, but I could probably borrow one. The spare graphics card I tested with was low-power which makes it more doubtful, but there's always a chance.

Is there any reason to believe you may have CPU damage (OC'd?) It's a long shot but its a variable you haven't tested.

Not overclocked and I can't see how I can try a different CPU without major hassle. It could be that, but given all the other symptoms (appearing to boot fine apart from lack of display), I tend to doubt it. CPU failures are, I believe, generally catastrophic rather than device-specific.

Check your motherboard manual. POST beeps are actually indicative of hardware problems, and the type of signal can tell you what it is. In your case, this means "monitor or graphics card error." Which, given the other things you've tried, means that your graphics card slot is probably hosed.

Where did you find this info for the GA-P35-DS3L? I looked, but couldn't find a POST beep list for it. There isn't one in the manual.

The last thing I'd check is taking your card and using it in another motherboard. It's possible that both the card and the board are fried.

True - good point.

Could be a leg of the power supply and a little easier to check.

Again, good point. I can try switching to a different leg.

I've also had bad fans presumably trigger safeguards to the power supply which may be disabling part of your board.

I'm trying to remember if the fans I have are smart enough to do that. Will check later.

Another quick and cheap check is replacing the CMOS battery on the motherboard, although that doesn't sound like your problem here, a bad battery sometimes causes strange things to happen.

I thought about that, but couldn't see how it could lead to the symptoms above. I can give it a try, though - not a hard thing to rule out.

You could also try unplugging every component you can (hard drives, DVD, network cards, fans) to see if that helps.

As above, I'm planning to do that this evening. However, since the PC appears to boot fine apart from the lack of display, I'm not hopeful that it will help.

If you have more than one memory module take all but one out and rotate them.

Done that. See step 5.
posted by Busy Old Fool at 7:32 AM on July 28, 2011


It's on page 77 in the link I provided, under Section 5-2-1, Troubleshooting, FAQ.
posted by valkyryn at 7:37 AM on July 28, 2011


Sorry, somehow didn't see the link in your answer. I was looking at the paper manual that came with the motherboard - I didn't realise there was a more complete one available online. Thanks!
posted by Busy Old Fool at 7:44 AM on July 28, 2011


If you don't need high quality video you could try a PCI based video card and see if that works. They are super cheap or maybe one of you friends has one laying around. This would be a good test to see if it is your PCI express slot that is causing the issue.
posted by white_devil at 8:29 AM on July 28, 2011


You could try to cardboard test* with the least amount of components needed to connect to it as possible. It is very useful in ruling out pretty much everything.

*Running everything outside of the case preferably on a non-static surface such as cardboard etc.
posted by lizarrd at 9:50 AM on July 28, 2011


Your PCI Exress slot is probably shot. If you really want to retest, I agree on the PCI video card. If you have a used computer store nearby, you can probably get one for a couple dollars if they happen to have any. I'm sure you could find one on eBay for less than $10.

One the upside, those boards are going for about $50 on eBay.
posted by cnc at 1:07 PM on July 28, 2011


This is likely the PCI-e slot....most common cause would be a bad capacitor supplying power to that slot. (You can check your motherboard for signs of bulging capacitors to verify.) Capacitors are cheap and easy to replace with a steady hand...but motherboards are also not too expensive as others have noted...just make sure you get one that has a matching socket type for your CPU. If no bad capacitors are visible, it could be a smaller less common component that has failed.

The fact that it has booted up in the background however with different cards makes me doubt the power supply....but I've seen stranger things so that's definitely worth checking out as well.
posted by samsara at 2:09 PM on July 28, 2011


A very late follow-up, but since sales of benzodiazepines have risen to combat the sleeplessness caused by not knowing what happened to my PC...

Taking white_devil's advice, I wandered into a tiny local shop and picked up an old PCI card - it worked fine! At that point I assumed it was probably the PCI Express slot. Following valkyryn's suggestion that the original card might be hosed as well as the motherboard and remembering Samsara's mention of capacitors, I checked and indeed they were bulging, bringing back memories of doing IT support for an office full of Optiplex GX270s a few years ago.

At this point I luckily had access to a friend's brand new gaming card and, since the machine was open anyway, I stuck it in - and had a lovely display again. This was strange, because almost the first test I did (number 2 in my question) was to swap my card with another PCIe one borrowed from a technician friend - so why hadn't that swapped card worked? When I visited them, they picked it out of a pile of spare parts, stuck it in an open case and it worked fine. Either there was some incompatibility (I thought all PCIe cards worked with all motherboards, but there's lots I don't know about hardware) or it somehow died on the way to my house.

Anyway, I bought a nice new low-power card and all is well again. Thanks everyone for the suggestions - they helped me get there in the end!
posted by Busy Old Fool at 11:48 AM on May 6, 2012


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