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Odd system failures, unable to pinpoint the problem

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Hello all,

I have a strange problem with my current system, I'll try to describe it as clearly as possible.

Current system specs:
Core2Quad Q9400 2.66GHz
1x 2Gb Kingmax DDR2-800
1x 1Gb Transcend DDR2-800
Asus P5KPL-AM
Palit GeForce GTS250 512Mb
Thermaltake TR2-500 500W
1x Seagate Barracuda 250Gb SATA (OS)
1x Seagate Barracuda 1Tb SATA
Running Windows 7 Ultimate x64

Turning the machine on, the CPU and graphics card fans turn correctly, but it does not POST. I have unplugged all of my hard drives, graphics card, and DVD drive, but still nothing.

I tried unplugging both DIMMs and got repeated beeps after starting up - does this mean the motherboard is working fine?

The interesting thing is, if I only plug the Kingmax DIMM into slot A, the system beeps and POSTs correctly, but I can never get past the windows splash screen, it either restarts/freezes there, or it never shows the splash screen after POSTing and the screen stays blank. Plugging the same DIMM into slot B also causes the screen to stay blank.

Inserting the transcend DIMM into either slot causes the startup beeps to disappear and the screen simply stays blank.

I tried testing the voltage levels on my PSU and the 3V, 12V and 5V standby are all correct, although the PSU fan is not spinning. Which is confusing, since the system can POST fine with 2 hdds, plus a fairly power hungry graphics card, leading me to believe that the PSU is fine, plus it's not even a year old. I have not tested it with another PSU though, don't have access to one at the moment.

Could it mean that one of my DIMM slots somehow got damaged? Perhaps from incorrect voltage from the PSU - how likely is that? Or is the PSU the only problem? Can it be related to software? Seeing that I have tried running startup repair but it freezes after a couple of minutes.

Thanks for your time
Jaco

More about : odd system failures unable pinpoint problem

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Does sound like maybe a RAM issue, I would download memtestX86, burn it to a cd and boot from it (if you can) and run a few passes with it. That should indicate if a stick is bad.

I remember having a similar issue with an old GFX card (X1950XT) in that I'd have to reset the machine repeatedly until it POSTed. It could have something to do with your problem. If you have one spare, try an alternative GFX card. You can pick up a crappy low end one for peanuts online.

Best solution

Power supply Master
Graphics card Expert

Quote:
The interesting thing is, if I only plug the Kingmax DIMM into slot A, the system beeps and POSTs correctly, but I can never get past the windows splash screen, it either restarts/freezes there, or it never shows the splash screen after POSTing and the screen stays blank. Plugging the same DIMM into slot B also causes the screen to stay blank.

Potential memory error on the Transcend DIMM. You should run Memtest on both DIMMs to check for errors. In your current situation you'll need to create a USB boot disk, boot to the USB and run Memtest from it. Instructions: Go here and follow the directions:
http://www.bay-wolf.com/usbmemstick.htm

Then when you have the bootable USB stick go here:
http://www.memtest.org/#downiso
and get the "Download - Pre-Compiled EXE file for USB Key (Pure DOS)"

You should also check for bad caps on your mobo: http://www.badcaps.net/pages.php?vid=5
images: https://www.google.com/search?q=bad+caps&hl=en&biw=1513...

Quote:
I tried unplugging both DIMMs and got repeated beeps after starting up - does this mean the motherboard is working fine?

It likely means that your BIOS has properly identifed a memory error. You would have to check that against the beep codes for your particular mobo/BIOS. It doesn't mean that your mobo is 'good' just properly IDd an error.

Alright, so I managed to get the MemTest running on the Kingmax DIMM and it reported no errors.

At first I thought that the system would again refuse to boot with the transcend DIMM inserted, but I was wrong, it did boot but the memory test froze after about 5 minutes. I tried it a second time, and the test froze almost immediately. The third time I tried starting up, the system did not go into POST and I was stuck with a blank screen and no beeps.

Another odd thing is, with only the Kingmax DIMM inserted at the time, I had the original no-POST problem, until I removed my one SATA connector , this has occurred once before but I have been unable to figure out what is causing it because it seems to happen at random.

Looking at the caps on the board, it seems that there are a few (3 or 4) that are slightly swollen at the top, I had to look closely but they clearly stand out between the others. There is also one, between the north bridge and PCI-e slot that is slightly tilted and also a bit swollen at the top.

Also, from that website you've linked, the randomness of these failures seem to point to faulty caps, although I'm not sure if the swelling is enough to actually indicate a possible failure.
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Power supply Master
Graphics card Expert

Caps don't have to leak to be faulty...bulging is definitely a sign of bad caps. The bad caps would intefere with Memtest results. Looks like you need to replace the mobo.

Oh dear.

But alright, thanks for the help, really appreciate it.

I was looking at the Gigabyte B75M-D3H board, it's fairly cheap (seeing that I have to buy a new processor and RAM), supports Ivy Bridge CPUs, plus I don't need the overclocking capabilities and multi-gpu support of the H77/Z77 boards.

Nope, no overclocking whatsoever.

And I'm buying in South Africa, the board I linked is ZAR 837 (@ R8.36 per USD, that's $100) it's also the cheapest board I could find (between B75/H77/Z77 chipsets), with the cheapest Z77 board around ZAR 1200 (around $140), the ASRock Z77 Pro3.

That and an i5-3570k (around $280, i5-2500k is about $270 here) and 1x 4Gb Corsair Vengeance 1600MHz DIMM (around $40).

This probably seems very expensive, but with the import costs and the weak exchange rate at the moment, these are the cheapest available.
Power supply Master
Graphics card Expert

Don't get the K series CPUs unless you plan on overclocking; you're paying extra for the unlocked multipliers that you won't use unless you OC. I'd consider getting an i3 2120; it's more than sufficient for the GPU you're using. In other words, your system bottleneck will be your GPU until you upgrade it. That will remain tru unless you get a GPU mor epowerfull than around an HD6950.
Power supply Master
Graphics card Expert

If you think you want more power than the i3 2120, then look at something like the i5 2400 to save some money over the 2500k/3570k.

Makes sense, I've looked at the i5-2400, and I can get it for a tad more expensive than the i5-3450. Seeing that I'm buying 1600MHz RAM, I might as well get the Ivy bridge CPU, or would it be more sensible to get the i5-2400?
Power supply Authority
Graphics card Expert

If you are not overclocking and can get a 3450 for practically the same cost as a 2400, I would pick the 3450.

On NewEgg, the 3450 is only $5 more. Since IB uses 10-15 fewer watts than the 2400, maybe 20W after the VRM and PSU losses while providing 100MHz higher stock speed and slightly better IPC, you are going to earn that $5 back as power savings over the first year.
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