What blew?

[Knoxximus]

A buddy of mine decided to fool around with his cab when his air conditioner was out in his house here in LAS VEGAS (on a 112 degree day, no less).  I guess boredom has no boundaries.....anyhoo, it's ok for a little bit, then something "popped" and the system shut down.  He since cannot get the computer to power up and removed his hard drive in a panic.

What do you guys think blew out?  Processor?  Power supply?  This sound familliar to anyone?

[pointdablame]

well in general... "pops" in electronics can mean a blown capacitor.  You might want to look over the motherboard and make sure everything looks ok.  Look for dark burned spots, something not sitting right, or a completely blown apart piece heh.

Was there smoke when it popped?  It could be a number of things, and I'd say the best way to test it is to put one part at a time into another system, assuming your friend has that ability.  In my personal experiences, this stuff usually stems from a bad/faulty power supply.  If it IS the PSU however, there is always the chance that when it shorted/dropped/spiked/whatever, it took along some other pieces of the computer.  I've seen mobos and CPUs get damaged by a bad PSU.

I would swap in a new PSU first.  See if the system will boot.  If it does, run tests to make sure everything else is running ok.  Look for hangs, run burn in tests, stress the CPU/video card/etc to see if they will break.  After that, you'd want to start swapping parts if the PSU didn't fix it.

[Tahnok]

Have you tried cooling down the entire computer and starting it up again? I have heard of some computers that will shut down when they get too hot. Also, can you smell anything? If a component did burn then it will have a very distinct odor. I'm trying to think, is there anywhere that a fuse could have blown?

[RayB]

Well, follow the chain of power. That usually tells you what's wrong...

What do I mean?

Step 1.
Turn on the power. What happens? Nothing? Is there a Light on ANYWHERE? Do the Drives spin up? Is there a light on on the motherboard? Does the CPU fan spin?

If no to all the above: Power Supply is dead. No need for next steps.
If yes to any of the above: Then it's something beyond the power supply. Go to Step 2...

Step 2.
What is showing signs of power and what isn't?

etc...

Basically, when nothing is happening, it's the power supply, or maybe even your power strip. Check the power strip "trip" and reset it.

[Trimoor]

If no to all the above: Power Supply is dead. No need for next steps.

Not true, I have a motherboard with blown caps that would show no signs of life with a good PSU.

[Generic Eric]

Not that this applies to your current situation, but someone I know said he actually had a bad power cable.

I thought that was strange myself...anywho.

[RayB]

If no to all the above: Power Supply is dead. No need for next steps.

Not true, I have a motherboard with blown caps that would show no signs of life with a good PSU.

Hard drives, CD-ROMs and pretty much anything else not directly attached to a motherboard draw current directly from the power supply. So, if your motherboard is dead, you should still see "life" in those other devices.

[mattv]

You're both right

If your mobo is shot and you are using a reasonably modern PSU (ATX) then it is possible that the mobo header where your power switch it attached may not be passing the "power me on" signal to the PSU.

You can power on a PSU manualy by unpluging the ATX connector from the motherboard and shorting one of the ground lines (black) with pin 14 (the green wire).

A bent paperclip is the best way to do this, but you might want to do a bit more research first, sticking paper clips into electrical devices is generally accepted as a bad idea.

As for what went wrong with your mates computer? no clue.