I toasted my CPU or mobo, how do I figure out which?

[Kuroyama]

I fried either the mobo or CPU in my computer, how can I figure out which is the problem? Here's how I fried it, perhaps this'll suggest a problem.

I've got a Shuttle AK31A mobo and XP 1700+. Been overclocking at 1.85V for a few weeks (closed L1 and L11 locks), and yesterday I did a mod to raise the voltage. I ran it for about 1 hour at 2.0V with complete stability, except the +5V rail was around 4.9V, the CPU temp never went above 48C. It then did an instantaneous reboot so I lowered to 1.95V. This held for about 10 minutes and then rebooted. I played around with the CPU voltage but each time it rebooted in a shorter amount of time.

The final time the computer refused to restart. When I press the power button the fans all start running, the power LED on the mobo lights up, the LED on the CD player also lights up, and the LEDs on the keyboard start blinking. I guess the CPU or mobo got fried, perhaps because I got a drop of solder on some pins of the voltage controller and spent a lot of time with the soldering iron on the pins and perhaps mobo.

Anyways, any help would be appreciated.

 

[minendo]

From what I read in your post, I would say it is the processor. Do you have an old Duron/TBird you could pop in there and test it. It sounds like your mobo is still working since everything powers on, so I would say find a way to test the CPU first.

 

[Kuroyama]

The only other computer I have is a laptop, so no chips lying around to test with.

I should note that when I turn on the computer the CD player's LED stays permanently on, and the keyboard LEDS (numlock, etc) flash continuously. So it's almost like the power went on but the mobo isn't doing anything. Also, the reset button will not work and nothing at all is displayed on the screen.

If the mobo was OK then wouldn't I at least get the BIOS opening screen, followed perhaps by an error because it can't find the CPU?

 

[minendo]

<< If the mobo was OK then wouldn't I at least get the BIOS opening screen, followed perhaps by an error because it can't find the CPU? >>


I now am starting to think that it might be the mobo. You know anyone that has a mobo that you could test your chip in. Testing the chip elsewhere is probably your best bet. I do believe that you should get at least a BIOS screen when you power on.

 

[r0tt3n1]

When the system first boots, a RESET call is made to the cpu, which if not answered, the POST cannot continue. Soooo, that would indicate a faulty cpu. It sounds as tho your mobo is probably OK, powers up, LED's work etc...... most likley the cpu is fried. Were you going for the uber overclock with the voltage mod or what?!?!?

 

[Kuroyama]

I don't think I was doing much of an uber-overclocking. The 1700+ defaults at 1.75V (1.47Ghz). At 1.85V I could run it at 1.58Ghz (10x158). This didn't seem like much of an overclocking, and since I got a good HSF I wanted to push it more. Many people talk about running XPs at 2.1V or so, so I didn't think 2.0V would be a problem especially since the CPU temp never went over 48C. While adjusting the variable resistor for the mod, the CPU voltage did go as high as 2.2V for a few seconds or so, but I don't imagine that should be a major problem.

So, if I pop out the CPU I still shouldn't expect the BIOS to show anything on the screen? I was hoping there would be some way to get the mobo to identify itself as working, beyond its current status where it just seems to show that it can turn on and off.

I wish I knew someone with an AMD computer so I could try swapping mobo or CPU, but everyone I know has laptops or Intels.

This sucks if the CPU is fried, the mobo would have been cheaper to replace.