Diagnosing pc fault

I have a problem with my pc not starting up. Here is my specs

Intel core2 quad q6600
Asrock 4Core1600Twins-P35
4gb DDR2
Nvidia gtx 260
OCZ 700w

Problem is, pc turns on but there is no image on monitor. All pc fans will run and also there is light on my card reader and mouse BUT NOT on the keyboard. Therefore it should be safe to assume that there is current running through the motherboard and my PSU is working. However, the fan on the gtx 260 does not run. I therefore thought the graphics card to be faulty and purchase a gtx 460 and installed it. Pc turns on with the gtx 460 (fans for graphic cards does run this time) but with no image.

So the question now would be: Is the motherboard faulty or is the processor faulty?
16 answers Last reply
More about diagnosing fault
  1. ANS - Yes... {no way to know yet}

    Are there any beep codes?

    Hmm...one of those DDR3/DDR2 lovely MOBOs. Q - Did you also connect the 4-Pin MOBO PCIe Molex? Also, with the GTX 460 did you connect the {6-pin & 6-pin}?
  2. Yes the mobo supports ddr3. The 4 pin power is connected and so is the double 6 pins to graphics card. Computer was working yesterday with the gtx 260. It just suddenly self restart and there was no longer any image on monitor ( hence the initial diagnose of faulty 260)
  3. So the 'screen' is black with both the GTX 260 and GTX 460?

    Typically, a PC running then failing back and forth {run/fail} is indicative of a faulty PSU. Is this what's happening?

    Edit: If the PSU is found to be okay, and there are no 'beeps' + the GPU is ruled-out then 8/10 it's a bad MOBO.
  4. Make sure that BOTH six pin connecters are being supplied with power. GTX460 has two 6 Pin sockets, you need to use both of them.
  5. Stewie, appreciate the initiative but please...i'm not stupid. Furthermore, the gtx requires two 6 pins too! So yes, both 6 pins from psu are connected to either 260 and 460 whilst testing.

    i will try testing the psu with another pc. The motherboard/case does not come with a speaker so there is no beeping to listen for.
  6. Sorry, didn't mean it that way :P Apologies

    go ahead and test the PSU in another PC. If it isn't the problem then yeah, faulty Motherboard.
  7. You really need to hear the BIOS Beeps, otherwise it's rolling the dice. $4 -> http://www.newegg.com/Product/Product.aspx?Item=N82E16812201032 also pretty much any Radio Shack 'should' have one; call before driving around.
  8. I've removed the power supply and placed it in another working pc. Everything powers up except the cmos lcd display (asrock 890gx extreme 3) and also no display on monitor.

    Psu faulty or just psu cables powering the mobo?
  9. If the PSU has multiple rails then my assumption is the PSU is bad on one or more rails; replace PSU. So if I understood correctly the problem replicated itself: OLD PSU + Different MOBO.

    I prefer Corsair PSUs: Single Rail, Japanese capacitors, under/over/fault protection. A bad PSU can very easily damage ANYTHING it's connected to in it's faulty state. Therefore, the best method,I should have stated, is to try a known 'good' PSU and not visa-versa.

    For your rig and a single GPU GTX 460 + OC -> $80 TX650W http://www.newegg.com/Product/Product.aspx?Item=N82E16817139005 for SLI GTX 460 ; $120 TX850W http://www.newegg.com/Product/Product.aspx?Item=N82E16817139009
  10. Well i've tried my own antec signature 850w on the system and everything powers up and there is also no signal on monitor

    Safe to say both mobo and ocz is faulty?
  11. Maybe the MOBO too, but clearly the PSU is bad; both might have a warranty. Example http://www.ocztechnology.com/ocz-z-series-850w-power-supply.html {OCZ 5 Year Warranty}. Oddly, per your post the 24-pin/4/8-pin seemed to work. ASRock's warranty is typically 1 year, but often they can repair/replace cheaper then a new MOBO.

    Have you tried on the [1] 'Q6600' rig: 'working' PSU & 'working' GPU? ; [2] GTX 460/GTX 260 on the 'other' rig to rule-out GPUs? Sorry, on [2] I'm a little fuzzy there?!

    The MOBO 8/10 is bad if the GPUs and PSU are known to be 'good.' :(

    In my personal experienced I had (2) bad Antec PSUs take out (2) GPUs {popped transistors} on two identical MOBO within a month or two -- THEN I wised up about PSUs. $600 went bye-bye! As I mentioned a bad PSU can destroy pretty much anything once it goes bad. After that everything went on UPS & Corsair; not a problem, knock on wood, since.
  12. I no longer have warranty on this components =(. Got this components 2nd hand

    I have tried the q6600 rig with working psu( antec sg850) with gtx 460 & gtx 260 (both cards confirm working as tested on my own personal rig) and there is only fans spinning( case fan and gpu fan) but no signal on monitor.

    Guess i'll start looking for a new psu and lga775 mobo.

    Sad to see you have bad experience with Antec psu but it is no surprise if you bought all the Antec psu made by Channel Well, FSP and Enhance as they had high rma.
    Antec signature and all latest psus are made by Enhance now. Top notch with low ripples
  13. I realize the changes with Antec, it's hard to put your hand back-in the hornets nest ;)

    Let me know how it turns-out, remember there's a 20% chance your CPU is toast. The only 100% way is to test the CPU. I've seen BOTH a 'toasted' MOBO and 'toasted' CPU more less do the same ---- hence the Beeps!!!
  14. Solved. New mobo arrived and turns out both mobo and ocz is faulty...
  15. Peace at last!!! :sol:

    Damn PSUs!!! :fou:
  16. Just bought a corsair ax750. =)
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