PC Refusing to Boot - Possible PSU Problem?

Hello all,

My PC spec is as follows:

Mobo: Abit IP35 Pro
CPU: Q6600 @ 2.4ghz
RAM: 2x 1gb Corsair XMS2 DDR2
Gfx: GTX 260
PSU: OCZ StealthXStream 600w Silent SLI ready ATX2
Case: Antec 900

Looking for a little advice. Been using my machine for gaming quite a bit over the Christmas break. 2 days ago my PC refused to post, the error code on the mobo read "C1" which the Abit manual tells me is the Ram check. After that initial sinking feeling subsided (something only a PC enthusiast can empathise with!) I set to work identifying the problem. I removed 1 stick of Ram and to my surprise the machine booted as normal. I swapped the single sticks around and discovered both would boot fine if used individually. I further discovered that placing the sticks in non matching slots i.e. 1 in a blue slot 1 in a black slot worked fine. I suspected at the time that there was a fault with the mobo ram controller. The PC worked fine all day yesterday (marathon sesh of the new SW MMO!). Woke up this morning and tried to switch it on and the fans would spin for 1-3 seconds and then the machine would power down. Occcassionally it managed 10-15 seconds at which point it hung on error code "90". This is something related to BIOS. At no point would the monitor come on.

My suspicion was that the mobo had finally gone completely. I thought I'd have a crack at testing the PSU (not something I've done before) as I recently picked up a multimeter (and even learnt how to use it!). The results were pretty surprising:

Pin - Reading
1 - 3.27
2 - 3.27
4 - 2.65
6 - 2.90
8 - 0.18
9 - 5.03
10 - 7.17
11 - 7.05
12 - 3.27
13 - 3.27
14 - -7.09
21 - 3.04
22 - 3.10
23 - 3.11

I had my multimeter set to DC volt with a 20v range. The results look odd to me but I'm not 100% sure what I'm expecting.

So I'm looking for advice on the following if that's cool:

1. Is the PSU dead?
2. Could it have taken my mobo / CPU with it? Is there a way to check (no access to a second PC / other parts sadly).
3. In the process of removing my gfx card (to pull out the 2 PSU plugs) I noticed that the end of one of the gold contact strips (the outside one of the 4-5 grouped together) was missing. Around 75% of the contact is still there just the tip is missing. The small mark left my the mobo where it makes contact is not affected by the missing gold strip so it may not be a problem? Any way to check the card is ok? Can the gold contact be renewed? Could there be a small piece of the contact stuck in the PCI-E slot?
4. Unfortunately as the machine won't post I am unable to run memtest. Is anyone aware of another way to check my ram short of buying a new PSU and hoping everything works?

Thanks for your time and have a happy new year and all that.

4 answers Last reply
More about refusing boot problem
  1. http://en.wikipedia.org/wiki/ATX

    shows you the voltages you should be getting, looks like psu is dead, assuming you aren't using a bad earth as reference. Use the pinout to determine a ground, and then work the voltages from there.
  2. Thanks. The voltages are way out by the looks of it. I used pin 24 as the ground with the black probe working the red probe from pin to pin starting from 1 (skipping over any grounded pins).

    Any idea if the missing tip on one of the gold contacts on my gfx card is a problem? The fans still spin up fine for the brief amount of time the PC is on and the contact between the mobo and board appears below where the missing tip starts. Just a bit worried I could fry the new PSU due to a faulty contact between the mobo and gfx card. If there is any risk then I'll upgrade mobo, gfx, ram and PSU together.

    Thanks for taking the time to reply.

  3. If your voltage reading between a black wire and a yellow wire when the PSU is running is only 7 V instead of 12 V then the PSU is dead and needs to be replaced. ATX spec puts the minimum level for the 12 V rail at 11.4 V.

    It could have taken the CPU/motherboard with it, but there is no way to know until you get a good PSU in that system.
  4. Replaced the PSU with an Antec High Current Gamer 620w and all is well again.

    Thanks for the help.

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