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Pc wont boot and yes i did the wholreeeee checklst everything spins black screen

Last response: in Systems
September 28, 2011 11:05:23 PM

Hello, so I've been at my wits end for the past three days trying to get my 3 year old pc to start again. When i power it up all the system fans spin. No bios beeps but it never beeped so that doesnt help.

It was working fine saturday night. Then i go to use the pc and take it out of sleep mode. I hear a strange noise come from the computer. Then it shuts down. I try to power up again and it stays on for three to five seconds. Then shuts back down. I let it sit overnight.

Next day i remove and insert all the internals. Now the pc will turn on and stay on. Only a black screen though.

Amd 64 x2 something
Asus m2n sli deluxe mobo
Wd 320 gb hdd
Gts 8600 gts video or my gtx 460
Corsair ddr 2 4x 1gb
Rosewill psu or antec earthwatts 500 w

Ive tried reaetting cmos

Each ram stick singly in each slot

Swapping psu and vid cards

Tried running with just ram cpu and vcard powered

My thoughts are the mobo is dead. What so you guys think?


September 28, 2011 11:24:17 PM

Where is the strange noise coming from exactly? Also, did you make sure the monitor is working? but if it keeps shutting down, then there must be short circuit somewhere.
September 28, 2011 11:28:55 PM

Sounds like the MB, but did you remove it yet to make sure nothing underneath was shorting it out?
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September 28, 2011 11:36:06 PM

Chances are you blew a capacitor on your motherboard this is what a bad one looks like:

September 28, 2011 11:41:33 PM

The monitor is for sure working.

No busted capacitors from what i see. The led light on the mobo still lights up.

The noise came from the psu. Thats why i bought a new one i thought it was that for sure.

Nothing smells of burnt plastic or electronic device death either.
a c 122 B Homebuilt system
September 28, 2011 11:58:49 PM

The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different, but they all use a single short beep for a successful POST.

Breadboard - that will help isolate any kind of case problem you might have.

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 once you are finished.

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 (standby power supply): 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.

A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.

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, long single beeps, or series of short beeps indicate a problem with the memory. If you get short beeps verify that the memory is in the appropriate motherboard slots.

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.
At this point, if the system doesn't work, it's either the video card or an inadequate PSU. Or rarely - the motherboard's PCIe interface.

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.

September 29, 2011 12:07:05 AM

That would be really helpful but i dont have a system speaker. Im currently taking everything out to check for a short.
October 10, 2011 5:30:09 PM

I ended up replacing the mobo and CPU. The old rosewill 750 watt psu was not the problem. Works great now though
October 10, 2011 5:33:06 PM

There was a blown capacitor upon further inspection. Was there anyway to replace it?
a b B Homebuilt system
October 10, 2011 7:11:57 PM

You cannot replace capacitors.

you'll have to call the manufacturer and get it RMA'd if under warranty or buy a new one.

Jaytwo96 said:
There was a blown capacitor upon further inspection. Was there anyway to replace it?