Motherboard Autopsy

ardichokeardichoke Icrontian
edited July 2009 in Hardware
So... I've got a bit of a puzzle I'm trying to work out. Yesterday night I decided that the rats nest behind my desk had gotten as bad as I could stand and it was time to change. I shut down my computer, unplugged everything, set the tower aside and proceeded to organize and neatly bundle all the cables. I then hooked everything back up, booted into Windows XP and... poof... my NIC wouldn't connect to my network. No DHCP, set everything manually but still wouldn't talk to the network. That's odd I thought.... maybe it's XP? Reboot into an Ubuntu live session... same thing... no DHCP and won't talk to the network with manual settings either. At this point I decided to go to bed.

Got up this morning, tried things again, still the same thing. Oh well I thought, I'll just put my PCI wireless card back in and order a PCI NIC to replace the now non-functional onboard. So I shutdown, tear apart, install the WiFi card and hook everything back up. Hit the power button... all the fans turn on, power LED comes on, HDD LED comes on solid but I get no POST and no video. Oh that's effing awesome I say to myself. I proceed to swap out my video card, change my video card from PCI-E1 to PCI-E2, change RAM from slot 1&2 to 3&4, swap the RAM out with some spares I have lying around, tried with only one RAM module, unplugged all my HDDs and my DVD burner and CD burner. The only difference it made was when the HDDs were unplugged the HDD LED wouldn't come on. Still no POST or video. Everything seems to point to motherboard badness (or, slight possibility, power supply). I have ordered a replacement motherboard and power supply already (good deal on a bundle from NewEgg) and got 2 day shipping so I should have it by Friday at the latest and should be back up and running after swapping it out.

Now then... getting to the point of my post... during this whole process I noticed that on my motherboard there was a PCI-E 12V plug that was a standard molex connector. I didn't have this plugged in for some reason and have been running like that without issue for months at the very least. My question I'd like peoples input on is.... do you think that not having this plugged in could have caused my board to fry somehow? I would think that not having this plug attached would, if anything, just cause the board to be underpowered and not function til I plugged it in not fry it... but I'm wondering if maybe I'm wrong on that and that lacking the PCI-E 12v connection somehow caused my board to diaf. What do you all think? :confused2

Comments

  • SnarkasmSnarkasm Madison, WI Icrontian
    edited July 2009
    I've seen standard molex plugs on mobos that were there to provide extra juice if you were running two graphics cards. It wouldn't be there if it was going to kill your computer.
  • lordbeanlordbean Ontario, Canada
    edited July 2009
    Sounds like a dead north bridge to me. On my old Asus P35-based board, the northbridge died right in the middle of memtest86+ stability testing, even though the ram was reporting no errors after 24 hours continuous run. I pressed CTRL-ALT-DEL to reboot it, and that was it - no post.

    I'm pretty sure it died of massive overclocking. I'd had the FSB @ 450MHz for several months and that board was rated to run 333MHz maximum.
  • ardichokeardichoke Icrontian
    edited July 2009
    Good to know Snark. I was wondering what exactly that was for and why my system seemed to be running fine without it connected. It's so frustrating to have something die for no apparent reason like that. I tend to have problems with hardware randomly flaking out on me too. I tend to not overclock my systems due to that fact.
  • lordbeanlordbean Ontario, Canada
    edited July 2009
    I have only once before seen a motherboard with a 4-pin molex connector on it, and it was an optional replacement for the 4-pin CPU power plug (you didn't have to have both connected). Since yours was near the PCI-E slots, I've no idea what it would be for.
  • ardichokeardichoke Icrontian
    edited July 2009
    Right, not only was it near the PCI-E slots but it was labeled PCI-E 12V on the board. I'm thinking Snark is probably right that it was to provide more power to the board if I was running dual PCI-E video cards.
  • lordbeanlordbean Ontario, Canada
    edited July 2009
    Could well be. As a theoretical guesswork, if the board has a 20-pin primary power connector and yet supports dual video cards, it might well need extra power to run them. Maybe that's what the extra 4 pins on the new 24-pin standard are for? I don't really know.

    Is there an expert on motherboard power connectors in the building?
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