Motherboard Failure

thomas_22

Distinguished
May 1, 2011
3
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18,510
Ok, so I accidently hit the 'sleep' button on my computer while trying to restart due to keyboard problems, then my computer completely shuts off to everything. Pressing buttons on the keyboard will not start it back up as it normally should when it is in sleep mode.

When I hit the power button the computer will turn on, all fans will turn on, a few lights do what they normally do, and the red light on the front flashes once. After that nothing happens, my keyboard does not light up, my moniters do not show anything, and I can get no response from anything apart from the cd drive, which still opens and closes normally.

I have tried:
-Swapping out the graphics card to an older one, (still compatible), and there is no change.
-Removing one, then both sticks of RAM, and replacing them in different orders, there is no beeping when they have been removed, and nothing changes throughout.
-Pluging the power supply into a different wall socket.
-Restarting the computer.
-Turning the power supply off then on then turning it on.
-Unplugging and replugging the cables for the harddrive
I am pretty sure this is a motherboard problem, but I have no idea how it could have been caused, as it was not overheating or anything like that.

Does anyone have any helpful information on problems like this to confirm it is a motherboard fault?

System specs:
Windows 7 64 bit
Intel 3.0 GHz core 2 duo
Asus P5Q Pro motherboard
Asus GTX 570 GFX
Silverstone 650 W psu
2x Gskil DDR2 2Gb RAM
500Gb Harddrive
 
Solution
So it doesn't even display the BIOS screen or anything, pressing delete at startup doesn't show anything?

Try removing the mobo battery if you haven't already, that'll reset the CMOS to it's original state, and if lucky get your system running again.

remove-bios-battery.jpg



You have to pull the latch outwards first, then you can finish taking it out with a flathead screwdriver, and wait for about 30 minutes before putting it back in, then turn on the PC.

wiinippongamer

Distinguished
So it doesn't even display the BIOS screen or anything, pressing delete at startup doesn't show anything?

Try removing the mobo battery if you haven't already, that'll reset the CMOS to it's original state, and if lucky get your system running again.

remove-bios-battery.jpg



You have to pull the latch outwards first, then you can finish taking it out with a flathead screwdriver, and wait for about 30 minutes before putting it back in, then turn on the PC.
 
Solution
Work systematically through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-posting-boot-problems
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.
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.
http://www.tomshardware.com/forum/262730-31-breadboarding

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: 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=youtube_gdata

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.