Troubelshooting Homebuild

Hi All,

Back in December of 2007 this forum helped me piece together a great machine that I built for my kids for x-mas. It was my first solo build ever and although it wasn't completely without issue it went easier than I anticipated (maybe too easy!). The kids loved it and we had no issues until a few months ago. The kids said the PC wouldn't start...took a look at it and the thing would just go to a black screen upon power POST, no splash, no DOS cursor, nothing! There were no system beeps either. All the fans were running though and mobo had power.

When I finally got around to opening the case up I noticed the stock HSF was loose...I assumed the cpu fried...I took off the HSF and removed the CPU and looked it over. I did NOT notice ANY burnt discoloration...nothing at all. I thought that was a good sign and I applied some AS5 and reseated the HSF. That did nothing. As a matter of fact, not only was the screen still black when powering up but now, after letting it run for a couple of minutes the PC just shut itself off. Now, evertime I start it...I get the same black screen and the PC shuts down itself after about two minutes...every time.

Is this basically a guaranteed sign that the CPU is toast and I should just by a new one? Or could it still be something else? Video Card? HDD? Any thoughts? Oh, and to round out the picture, I made sure it wasn't the monitor as I hooked it up to MY monitor which I know works...I also reset the CMOS battery.

Here are the specs of the machine:


CPU: INTEL Core 2 Duo E6750 2.66Ghz Retal Box

GPU: nVIDIA 512MB 8800GT (EVGA Version that comes w/Crysis)

MEMORY: CORSAIR 6400C4 2X1GB (TWIN2X2048-6400C4 Kit)


HDD: SEAGATE 320GB Barracuda 7200.10 w/Perpendicular Recording Tech

ODD: SONY Optiarc DVD/CD ROM 16X/48X Combo

OS: MICROSOFT Windows XP Pro w/SP2

Thanks in advance for any help/guidance you can offer!!
13 answers Last reply Best Answer
More about troubelshooting homebuild
  1. Best answer
    Follow the sticky that reads something like "READ THIS BEFORE POSTING NO BOOT/VIDEO PROBLEMS"
  2. Here's a link to the sticky mentioned. It was created to troubleshoot this exact type of problem. Let us know how it goes after you've performed every step in the checklist.
  3. Hi cmcghee & shortstuff,

    Thanks for the link to the sticky. Yes, that checklist is complete.

    1. Yes
    2. Yes
    3. Yes
    4. Yes and reseated it twice.
    5. Yes
    6. Yes (and please note this build ran fine with no stability issues for over 2 years.
    7. Yes and repeatedly as I swapped modules and tested with only 1 for step 6.
    8. Yes
    9. Yes (and again...PC has been running with no issues for over 2 years)
    10. Yes (and reinstalled correctly as well after I took it out to check for burn damage or discoloration)
    11. I was using stock HSF (although...since posting I have upgraded to a Xigmatek HDT-S1283 which has stopped the auto shut-offs).
    12. Yes and since I installed a new HSF that was done again.
    13. Yes and has also since been replaced with a new cooler
    14. No and no.
    15. I always wear a ASD strap when working with the PC so I sure hope so.
    16. Yes and was verified with beeps after forgetting to plug in the power cable after reseating the GPU card the 1st time (and during boot-up with no mem dimms)
    17. Yes
    18. Yes and there this is not plugged into a GFI.
    19. I have not upgraded the bios version since original installation and again PC has been running for over 2 years)
    20. Yes. I removed the battery, changed the jumper, waited 60 seconds, changed back the jumper and re-inserted the cmos battery.
    21. Do not have integrated video that I know of. Also, I didn't pull the mobo out but I did remove all components and add them back one by one. Never got a post.

    I am thinking, in this order:

    1) CPU got fried (maybe I didn't seat the stock HSF good the first time and with my 3 kids jumping around for two years the weak link finally popped (leading to the loose HSF I mentioned in my first post). Additionally, my kids told me that before it went to nothing but black on boot-up that it would run for five minuted and then turn off...which to me is a sign that the CPU was overheating and protecting itself...and then it finally fried?

    2) GPU Card went bad

    3) MOBO damaged (but I doubt this)

    Do you agree or are there still some other checks I could do? Again, thanks in advance for your help!!
  4. I dont know the steps by heart, but have you breadboarded it yet?
  5. I would put the GPU as a less likely cause for the problem. When my GPUs went bad in the past it resulted in getting to windows and having lines all down the screen. I would not have thought it would cause the computer to keep turning itself off so early in th start up process.

    You have your own monitor, does that mean you have a computer and graphic card? If so you can definately remove the GPU from the equation by using your one in their computer or their one in yours
  6. I'd be willing to bet it's in order of Motherboard 1st, CPU 2nd in likelihood. The fact that you said it won't give you an error code or beep leads me to believe that the motherboard isn't doing it's job IE: it can't because it's dead.
  7. Well, I believe you may be right about the motherboard. I was convinced it was the CPU so I bought a brand new Q9550 and replaced the e6750. Not only did it not boot up but it went into a repeating on off cycle. It powered on for 2 or 3 seconds, fans spinning, lights humming, and then shut down for 2 or 3 seconds, then back on wouldn't stop unless I forced a shut down or pulled the power plug.
    I thought maybe the CPU I bought was not a fit for my mobo but I checked on the Asus site and it listed as OK. Well, I still went ahead and put back the old CPU to see if this new symptom didn't. The same thing happened.
    So I breadboarded the mobo on the anti-static bag it came in placed on top of some cardboard (I hope that was OK). I put back the Q9550, plugged the fan in and the power supply and nothing else. I used a screwdriver to make the connection between pins to power the thing on and it turned beeps...but shut off in 2 or 3 seconds again. Although this time it down not power back up. Is that significant? I could keep powering it on but after 2 or 3 seconds it would shut down...but no power on again without me making a renewed connection.
    Based on what I read I guess this leaves the PS and the mobo. Unfortunately I do not own another PS to test this. So, any ideas? I am really leaning towards the mobo as the culprit and am wondering if I should just bite the bullet and get another mobo. I doubt it is the brand new CPU (although I guess there is a slim chance of that).
    Please let me know your thoughts...thanks!
  8. Based on the behavior, I'd go with the motherboard. I suppose I may sometimes leap before I look, as theres no way to tell 100% without the proper tools (since neither of us have them), but if you were to offer me a bet, I'd put everything I had on the motherboard and hope I'm right (then again if your mobo is bad it could have fried both CPUs which would make it look like I was wrong). I'd say swap the board or get a test kit to be sure. I'd swap the board or do both, since getting a test kit first would just be a waste of time.
  9. Take the whole thing apart and rebuild it... helped me fix my first pc.
  10. Or if you have the money just trash the system and build another if all else fails.
  11. Hey All,

    I am posting again as this has been resolved and so I thought the results might help someone else that comes across the same issue. It turns out it was at least the motherboard AND one dimm of memory.

    I breadboarded the thing again and heard no beeps whatsoever. I ended up buying a new mobo (Asus P5Q Pro Turbo) for about $100 and breadboarded that as well. Installed everything again piece by piece and it worked fine up until the memory. I was not receiving the beep code for no video support. It turned out one of the DIMM's was bad as well and I didn't get the no video beep because it didn't past the mem testing part of the post. If I just used the one good DIMM everything worked great. I have the thing up and running (with only 1gig of ram) and it is running awesome. CPU temp, according to Asus PC Probe II, is hovering between 36 and 39 at idle with stock HSF that came with Q9550.

    It turns out my p5k-e wifi/ap is still under warranty (of course my retarded self didn't figure that out until after I bought the new one) so I RMA'd it the other day. When (assuming) I get a replacement, I will try the original e6750 and see if the CPU is damaged at all.

    But as of right now, it is definitely confirmed the mobo and one DIMM was bad.

    BIGGEST LESSON LEARNED TO TAKE AWAY FROM THIS: They (the forum gurus) aren't kidding about the helps to answer a lot...and don't skimp. I breadboarded to begin with but in hindsight I realize I didn't do a true step-by-step rebuild when breadboarding due to my bias that memory (and at first mobo) weren't the real culprits. For anyone else out there that is, unfortunately for you, not so bright like I am: do it right the first time!

    As always, you guys were all awesome...your advice helped so much...thank you, thank you, thank you!
  12. 13bravo said:

    Based on what I read I guess this leaves the PS and the mobo. Unfortunately I do not own another PS to test this. So, any ideas? I am really leaning towards the mobo as the culprit and am wondering if I should just bite the bullet and get another mobo. I doubt it is the brand new CPU (although I guess there is a slim chance of that).
    Please let me know your thoughts...thanks!

    You are right, with the new CPU, that pretty much leaves PSU or motherboard.

    The best way to check the PSU is to swap it with a known good PSU of similar capacity. Brand new, out of the box, untested does not count as a known good PSU. PSU's, like all components, can be DOA.

    Next best thing is to get (or borrow) a digital multimeter and check the PSU.

    Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

    The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

    You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.

    This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU. You can carefully probe the pins from the back of the main power connector.
  13. Best answer selected by 13bravo.
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