Troubleshooting - DOA

I was asked by a friend to diagnose a problem with her PC, and I'm stuck at the moment.

Here's the backstory:

The PC was working fine for about 6 months, absolutely no issues. One day she came home and it simply did not start. No lights, no fans, nothing, almost as if it was not plugged in. I tested the PSU, jumped it and everything tested fine, 12v, 3.3, etc. I tried to jump the mobo with a screwdriver thinking that it could have been the power button, nothing. Uninstalled everything and put it back in, nothing (even took out the CPU and re-pasted it). Since I am not even getting fans I figured the mobo could have been fried. It is hooked up to a surge protector, but there was a nasty lightning storm the week this happened. We RMA'd the mobo and when I installed the new one, it was still dead. No fans, no lights, nothing at all. My only other thought is that the CPU fan is dead and it will not start without a working fan. Is that even true for some boards?

I am either missing something obvious which is possible, or I have a DOA motherboard from the RMA. TIA for any ideas.
6 answers Last reply
More about troubleshooting
  1. How exactly did you test the PSU? The fact that it doesn't start up at all would indicate a PSU problem. Is this a pre-built OEM system or a homebuilt system? Do you know anything about the hardware? It's a little easier to troubleshoot if you know what you're working with.

    Have you tried each stick of RAM by itself?

    Here's a checklist to give you a methodical method of troubleshooting:
  2. I read through the checklist and I feel like I did all of it just out of habit. I will however go through it step by step again. I did check each stick of RAM on its own and had no luck. I even tried without any RAM to see what I got.

    I plugged the PSU into the wall, jumped it with a paper clip, and got a voltmeter on it. Everything checked out as far as I could tell. The system is a homebuilt and off the top of my head has the following:

    Intel based system, 8400 C2D, 2x1GB G.Skill, 250GB WD drive, Gigabyte mobo (I'll double check the model), GeForce card (double check the model as well), stock CPU fan, all in an Antec 300 case.

    If it sounds like I missed something with the PSU please let me know. It was the first thing I thought of and even when it tested out, it was nagging at the back of my brain.
  3. What PSU is it? Jumping it and testing it with a voltmeter is a good start, but it still sounds like a PSU issue to me. You don't happen to have an extra PSU you could try in the system do you? If it's a cheap PSU it should be replaced anyway.
  4. It is a Corsair 520w or 620w I believe. It is definitely a good PSU. I thought about just swapping my own out to check it for the hell of it. Truth be told I think I will see if I can do this tonight.

    I definitely agree with you that all reasoning leads to the PSU. My question is, why would it check out voltage-wise and still be bad? I don't have an in-depth knowledge of electrical systems and circuits so my information base is admittedly limited.

    Thanks for the advice btw.
  5. Do you have a system speaker installed so you can hear the BIOS error beep codes? The motherboard should have been beeping like crazy when you tried to boot with no RAM installed. Do you happen to have any known working RAM you could try in the system? It's possible the lightning storm could have taken out both sticks of RAM.

    Yes, Corsair PSU's are excellent. Of course any component from even the highest quality manufacturer can fail. Jumping the PSU and testing the voltages is a good way to tell if it's completely dead, but it isn't testing it under any sort of load.
  6. The mobo never got a chance to go crazy because it never started up. No joke, this thing acts like it isn't even plugged into the wall. I set it up so that I can get a look at it after work. What I'll do is try my own PSU in it to start with and go from there.
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