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Need help troubleshooting a possible serious problem

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  • Homebuilt
  • Systems
Last response: in Systems
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January 10, 2012 1:40:53 AM

Let's start of with these symptoms

Currently:

The cpu fan is not on although it does work because i switched the connection to the case fan and it did come on, the cpu is not on I know this because it does not get hot at all. The hard drive is on and does spin when the computer boots, the video card fan spins and the card warms up, the motherboard feels as if it is getting warmer as well, particularly on the nb connection and the psu fan does not spin.

Right before it happened:

All this occurred this morning when I went to turn the computer on it sounded like it was working but i could smell a faint burning smell. I instantly turned everything off and opened up the case. I couldnt see smoke anywhere and the smell was virtually gone. I tried to boot it again and the fans came on, the mb standby light came on and the hdd spun but there was nothing on the monitor just a blank screen.

The night before I had been playing skyrim on ultra settings with the cpu oc'd at 4.3 ghz. I was monitoring the system and the max temp the cpu reach was 50 C and the max temp the gpu reached was 61 C. I powered it off like normal and went to bed.

Past problems:

The only other problem I had with this computer was a few days ago during the build. After everything was in I went to hit the power button, with the case cover off I hit the power button and then I heard a pop and I saw it come from the psu. This was the first time it had been turned on. I tried breadboarding it and the system did cut on. So I figured it was a small short or something and put everything in the case. Up until this morning everything else was fine.


What I have done so far:

I bought a corsair ax750 psu and tried that, no luck. I took the hard drive out and connected it to my laptop and it booted up like normal. I have reseated the ram stick in every slot multiple times. I have hit the memok button but it just keeps blinking forever. I have reset the cmos and reset the bios by taking the mb battery out.

question... would resetting the mb and the cmos cause it to lose any updates to the bios, if so then the mb I am using requires an update to run am3+ sockets. Without it, it can't run my fx-4100.

There are no beeps and the system has never posted since this morning.

My specs:

M4a89gtd 890gx motherboard

fx-4100 cpu

560gtx sc gpu

corsair 4x1 vengeance

(new) corsair ax750 psu

More about : troubleshooting problem

a c 122 B Homebuilt system
January 10, 2012 2:15:11 AM

No beeps? Do you have a case speaker installed?

Back to the breadboard ...

The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread.
http://www.tomshardware.com/forum/261145-31-read-postin...

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-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 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. The green wire should also have 5 volts on it. It should go to 0 volts when you press the case power button (this is also a good way to test the power switch and the associated wiring), then back to 5 volts when you release the case power switch. 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...

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.

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January 10, 2012 2:53:21 AM

Useful info but not what Im looking for. The psu is brand new so i know its good. I will true the paperclip trick and are if the fan comes on. I don't know why it wouldn't be coming on. if the power supply turn on with the paperclip but not when connected to the motherboard then I'm guessing the motherboard is the problem. could someone please answer the question about clearing the cmos I need to know if clearing it wold erase updates on the bios
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