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Video Signal Lost, or Computer Locks Up

Tags:
  • Computers
  • Overheat
  • RAM
  • Video
  • Motherboards
  • Graphics
  • Graphics Cards
Last response: in Graphics & Displays
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August 3, 2014 7:55:56 AM

I had a somewhat dated HP computer that had stopped displaying any video signal whatsoever.
No BIOS on motherboard and no beeps when I removed all RAM, so I assumed the motherboard was the problem and decided to start a budget build after salvaging what was left of the old computer
My new computer build has the following:
PSU: 430w Corsair CX (new)
MoBo: ASRock A785GM-LE (new/refurbished)
RAM: 2 GB generic
CPU: AMD Athlon II X2 4800+ 2.8 Ghz
GPU: EVGA GTX 650 (not ti) 2GB overclocked (new/refurbished from newegg)
HDD: 1TB Western Digital

Case is from an old dell optiplex because my last computer was mini-ITX
Im using an external DVD drive for installation

My problem now is when using the integrated graphics the system boots fine and acts normal, but after a few minutes of activity, the video signal will cut out completely, and my screen will search for a signal. Nothing ever happens, and I have to shut down the computer from the power switch on the PSU.
I thought the problem had gone away, so I tried installing the graphics card. Everything seemed normal, and It runs for about five or ten minutes, but always locks up and freezes. The display still keeps an image but the computer is completely unresponsive and I cannot move the mouse cursor or use the keyboard.
I assumed this was due to overheating, so I cleaned the heatsink/cpu and applied arctic silver 5 per instructions. I went into the BIOS to watch the temperatures, and as soon as the CPU would reach 35c/ 96f is when the computer would lock up. This happened twice. The Computer becomes unresponsive while in the BIOS menu and I have to hard reboot like always. I couldn't check the GPU temperature at the time, because the computer locked up during a clean install of windows, so I have no OS to test now and must install windows onto my hard drive from another system or use a liveCD to check the GPU temperature, which I haven't done yet. the fan does spin on the graphics card, but I already had to replace the fan because I broke a few blades off of the first one. Also, I tried booting with the graphics card and without the hard drive, but it still locked up as soon as it hit 35c.
Since the computer was locking up at the same time every time I booted it, I figured it HAD to be a heat issue and removed the graphics card. I'm assuming the replacement fan isn't strong enough and am setting the graphics card aside until I get the system functioning fully. After removing the graphics card there was no lockup at 35c in the bios, but when I exited and went to install Windows I get back to the black screen/loss of signal after 3 minutes or so.

The only think I haven't replaced or swapped out is the RAM. I've been using one of my two sticks through this entire process in order to narrow down the possibilities. I will try the other stick of ram with just the CPU and HDD and see what happens

Is this black screen a motherboard short? because the risers all fit and the motherboard doesn't seem to be touching the case anywhere.
Why doesn't the black screen happen if I use my graphics card? Could the freezing AND video loss have been the RAM instead of the graphics card this whole time? I also have my old GTS 250 that I'm assuming still works if anyone thinks it would be a good idea to try. I ordered the GTX 650 because I assumed my last computer just needed a new graphics card, but it ended up being the motherboard.


Update: I removed some extra pci brackets from the case that were touching the motherboard slightly and I switched out the panel power button with the one from my old AMD HP system to reduce the possibility of shorting because the one in this case was with an intel based system, I also disabled the floppy drive in the BIOS.after booting for the same purpose. I have a PSU tester and the PSU shows it's fine and the voltages look good in the BIOS

Results: With A different RAM module and the HDD disconnected (only CPU, 1x 1gb RAM, onboard video) the BIOS didn't seem to give any problems after I tested it for a few minutes. I will see what happens when I try to install windows on the hard drive, and maybe give the GTS 250 a try if everything goes good.




More about : video signal lost computer locks

a b V Motherboard
a c 118 U Graphics card
August 4, 2014 4:12:10 AM

I see there are only 2 ram slots in your motherboard. I suggest you try the ram stick that is working in both the slots and see which slot gives you the error. Post back here. Another thing try your hard disk on each and every sata port and see if any port gives the error. Try these test separately and post back here.
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August 17, 2014 10:40:00 PM

Okay, I figured it out. The black screen stopped happening after I made sure that none of the cases unused pci brackets were touching the motherboard, and I pushed the PSU connector all the way in to where it latches completely even though it felt like I was going to break the motherboard.
The graphics card was freezing even after I replaced the old fan with a fully identical one, but it was lasting longer than before without freezing and only froze when I tried to play a game. I soon realized this was because the fan speed was stuck at 21% and it wouldn't raise even when the temperatures did (it never got above 60c though). I downloaded EVGA precisionX and set a new power curve for the fan, and everything seems to be running fine now.
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August 17, 2014 11:17:58 PM

I guess I posted too soon. It worked longer and better than it has so far, I was about ten minutes into a game of DOTA 2 when it froze again, and the GPU temp was only 35C.
I'm guessing this is memory related now, and I don't think it's the hard drive. I'm leaning toward the RAM but all I have is two mismatched modules from several years ago that were in my old PC that stopped working. I will try running on a different hard drive and will eventually buy more RAM if that doesn't work.

side note: I just played another 15 minutes or so and finished the game that had frozen. I did this right after rebooting from the freeze. They really seem to happen at random times now, instead of just being related to overheating. My GPU temp never went over 40C, so now I'm really confused. At least it doesn't seem to happen as often as before.
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a b V Motherboard
a c 118 U Graphics card
August 18, 2014 7:58:59 AM

To me it is relating to either the processor or the motherboard. Try couple of things first, remove the heat sink and see if the processor is correctly seated in it's place and see that no pins are bend. Then try removing the ram's and only try one ram if it is mismatched ram's then it shouldn't lock up, also make sure the bus speed of the Ram's match or they will cause lock up. Also remove the graphic card and run on integrated and if you got some kind of game that doesn't require graphic card run it and see if it gives you the lock up.
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August 18, 2014 10:25:30 PM

Thanks! I thought about what you were suggesting and it really made sense. I thought it was strange that I could leave the computer on for hours with absolutely no symptoms and do things like download steam games and even play minecraft in the meantime but it would only freeze under "heavy" load. I reapplied thermal paste once and I thought it was stranger that none of the temperatures were reaching high levels anymore (nothing above 40c). Turns out I was just expecting a little too much out of this little old processor. I'm not sure if it's just gotten old, or I haven't used it in a while, but when I put DOTA 2 windowed in 800x600 with settings all the way down, both cores were reaching 75-85% and sometimes causing brief moments of freezing throughout the game when spiking to 99%. I guess the problem now is simply a slow processor. I mis-posted and it's only 2.4 ghz dual core, and I got it used about 4 years ago, so it seems like a reasonable cause. I'm glad it's not my VGA. I love all the information here by the way.
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a b V Motherboard
a c 118 U Graphics card
August 19, 2014 2:53:17 AM

Glad you got it resolved and to be honest it was a mistake from my side too, the first step would have been to check the usage of the processor but by your details i also got fixed on hardware error totally ignoring the real thing.
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August 19, 2014 11:17:18 AM

I'm not positive but I think the card was overheating at first, because I couldn't even install windows without it freezing until I put the right fan on again. When I finally got it running it just looked like it was the same problem but the cpu was causing the freezing. When I tried the GTS 250 it froze under load too, but I'm hoping it's definitely the CPU. Sorry for the extra details, it was all bothering me and I didn't know where to start.
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a b V Motherboard
a c 118 U Graphics card
August 19, 2014 11:58:05 AM

No problem, it was just that after all you did processor and the motherboard were the only things that remain and to me new motherboard was not that much of a great problem but sometimes new motherboards are bad but that is sometime. I tend to check old things first and then blame new things.
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