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HELP! computer wont turn on

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  • Prebuilt
  • Computer
  • Power
  • Systems
Last response: in Systems
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September 13, 2010 3:21:50 PM

hello everyone, I was watching a movie yesterday when my computer suddenly died! It was a regular day and Im sure I had no viruses or anything but My computer suddenly turned off and wouldnt turn on after. When I press the power button I get no response what so ever, no beeps, no lights, no fans. Its as if I didnt push the button at all

this is the computer Im working on

http://h10010.www1.hp.com/wwpc/ca/en/ho/WF06b/12132708-...

What Ive tried so far-

Ive tried moving the computer to a different room and using a different power cable- Nothing happened

I tried leaving it for a day unplugged- Nothing happened

I tried a Bare boot with hard drive, mobo, cpu/fan, 1 stick of ram- nothing

I tried reseating everything- nothing again

Removing cmos battery for 15 minutes- nothing

What I noticed though is that on the back of my computer there is a solid green light on the back of the power supply, So I know at least some power is getting to the computer right?

this leads me to believe that maybe the mobo is fried but im not sure(noob) So im asking here to see if anyone has any advice or could tell me if I missed anything?

Thanks

More about : computer wont turn

September 13, 2010 7:24:23 PM

Most likely the PSU is dead.

Only way to be sure is breadboard and use a different PSU you know works.
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September 14, 2010 7:30:47 PM

Okay so I just swapped the psu with my cousins tower and his turned on but mine stayed off. So Its probably the the Mobo, or the chip right? Although I have no way of testing the chip because I dont know anyone with a similiar socket board.
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September 14, 2010 8:10:49 PM

I agree with problem being the power supply..make sure that on the psu you have the yellow and black 4-pin connector plugged in. if it's not it wont start or you might get power without any video. also make sure on the psu if there is a switch by where the plug goes that it didnt get bumped..the "--" should be pushed down.
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September 15, 2010 12:59:54 AM

scione said:
Okay so I just swapped the psu with my cousins tower and his turned on but mine stayed off. So Its probably the the Mobo, or the chip right? Although I have no way of testing the chip because I dont know anyone with a similiar socket board.

Probably. Use a bright, small flashlight and inspect all the capacitors and voltage regulators on the motherboard for damage. If you see anything that looks like a little rust on them, its probably blown. The CPU being damaged is fairly unlikely, unless when you pull it out you see tarnish/damage to the pins.

http://www.techhandbook.com/files/imagehosting/10379245...
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September 15, 2010 7:20:32 PM

dndhatcher said:
Probably. Use a bright, small flashlight and inspect all the capacitors and voltage regulators on the motherboard for damage. If you see anything that looks like a little rust on them, its probably blown. The CPU being damaged is fairly unlikely, unless when you pull it out you see tarnish/damage to the pins.

http://www.techhandbook.com/files/imagehosting/10379245...


After closer inspection I didnt find any rust or areas where it looked blown, I didnt see anything unusual with the cpu either, Is it possible that the mobo just died?
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September 15, 2010 7:49:52 PM

Its possible something died with no visible evidence.
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September 16, 2010 5:10:36 PM

Work through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If not, continue.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different.

Breadboard - that will help isolate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboardi...

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.

Make sure you plug the CPU power cable in. The system will not boot without it.

I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case.

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps:
Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.

Silence or long single beeps indicate a problem with the memory.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.

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September 17, 2010 12:39:30 AM

Thanks guys for the help, I bought a new board off newegg and now im up and running again :) 
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