CPU or Motherboard?

[medrewry]

We had some violent thunderstorms several days ago and I came home to discover that the power had gone down at some point. My computer would not boot. It was left turned on, but hibernating (Vista Ultimate 64). I have a custom rig with ASUS P5K Premium MB, 4 X 1GB Crucial Ballistix, Q6600, PC Power and Cooling 610 Watt PS. When power is applied, the fans all spin and the lights on the Ballistix Tracers indicate some changes, but it never accesses the boot drive and there is no diagnostic beep and no video.

I swapped video cards, no change. Monitor works fine with my backup rig.
I figured that it was motherboard, CPU or power supply.
I checked the +5 and +12 with a multimeter and they both look good.
Is there an easy way to tell if its the MB or the CPU? I have a second rig (that I'm using right now), but I would rather not rip it apart to swap parts.

Thanks for any help.

 

[NoStateofMind]

Remove one stick of RAM and boot. If it doesn't boot, then move that stick to another slot and boot. If that doesn't work THEN try the other stick in the same fashion.

Try this and come back to us.

 

[medrewry]

At this point, I have removed the motherboard from the chassis and have it sitting on an insulated pad and connected to the PS. I have rotated two single sticks of memory thru all 4 DIMM slots and the result is always the same - no beep and no video.

 

[medrewry]

It seems to be failing POST. I am about resigned to do an "unplanned upgrade", but I would like to know which component to replace - motherboard or CPU. I am leaning towards motherboard.

 

[NoStateofMind]

It could be either one. If you're not receiving any POST beeps then you may need to get a new mobo/CPU. Have you tried clearing the CMOS? IDK just make sure you try everything you can before resolving yourself to buying parts.

 

[robisbell]

when you are testing it, are you using the same PSU, or a new one? what were all the voltages when you tested the original psu with a multimeter?

 

[medrewry]

I cleared the CMOS twice.
I only have one power supply unless I tear down my backup rig, which I don't really want to do.
I only check the +5 and +12 and they were both about .01 volts over (very close).

 

[NoStateofMind]

Now that I think about it it sounds like its stuck in hibernate mode. Can you swap out HDD and see if that it?

 

[medrewry]

I don't see how it can be stuck in hibernate. I have the motherboard out of the chassis. Its not connected to any hard drives and it won't get to the point where it beeps or outputs video. Its only connected to the power supply and it has a video card that is connected to a monitor. One stick of memory and thats it!

 

[NoStateofMind]

Yeah bro, It's gonna have to be a motherboard or CPU failure IMO. Wish I could help you more. Maybe you could get one of THESE (cheap) just to rule out which component.

 

[medrewry]

This morning I checked ALL of the power supply voltages +5 +12 -12 +3.3 and they were all within spec. The +3.3 was a little high (+3.4), but acceptable. Thanks for taking a look and making suggestions. I just have to decide whether to gamble on a CPU or a motherboard. I guess a CPU would be easier to sell on Ebay if it turns out that I didn't need it!

 

[robisbell]

I'd like to know what the actual readings were, but I will bet it's either motherboard or psu, or both.

 

[medrewry]

robisbell - I used a good multimeter (Fluke 83) and each voltage was slightly high (.01 -.03 volts) except the +3.3 which measured +3.4 volts.
All of these are within spec. I tested it with the motherboard connected to provide a load and I tested the connections on the main motherboard power connector. I'm pretty sure its not the power supply.

 

[conorvansmack]

If you have access to another board (friend or family) you could try your processor in there. If it works, then try the processor of your friend/family in your board. That could help you narrow it down. The problem is that you would have to find someone willing to do that.

 

[krnmastersgt]

Well then, you've ruled out the cpu(that might be as well but boards beep without them) and the psu(you trust your multimeter so we'll go with that). So you already seem to know that your board has bust.

 

[Cutthroat]

The surge could have come along your network cables and bypassed your PSU, you may have just fried your MB, and possible anything plugged into it. You should replace the motherboard first.

 

[medrewry]

Thanks for the suggestions. I ordered an ASUS P5Q Deluxe from newegg. It should be here tomorrow. I will post when I know if I guessed right.

 

[KurskKnyaz]

Originally posted by: medrewry

I checked the +5 and +12 with a multimeter and they both look good.

Thats not good enough. Try a different PSU.

 

[medrewry]

The new motherboard arrived and it exhibits the same behavior. Guess its the CPU (or possibly the PSU - even though ALL of the voltages read normal). I ordered a E8400 with one day shipping. This is getting expensive!!!

 

[KurskKnyaz]

Test the PSU first. I seriously doubt it fried the motherboard and CPU. You never tested the +3.3v anyway. Modern computer hardware has a lot of protective circuitry. I heard of surges frying NICs and modems. I never heard of a surge frying the motherboard and CPU.

 

[robisbell]

told you itwas probably the PSU. old otherboard may not be bad.

 

[medrewry]

My new CPU won't be delivered until Monday. Since I had some time this weekend, I removed the PSU from my backup rig. No change, still no video.

 

[medrewry]

Well, it turned out that the problem was the memory. I was testing the memory by rotating ALL FOUR 1 GB DIMM's through all four slots. I thought that there was NO chance that all four DIMM's were bad. WRONG!! I was VERY disappointed when I installed my new CPU and MB and it did nothing! I scratched my head for a while and decided to try one DIMM from my backup rig and it booted. I then tried the good memory DIMM with the original CPU and MB and that booted.
Anybody want to buy a Q6600 and ASUS P5K Premium Black Pearl Edition?

 

[Dillybob]

Glad to hear everything works!