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Computer Hardware Issue (Big Problem)

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January 15, 2011 4:49:07 PM

So, here's the story. I have a fairly decent computer, homebuild of course. I'm running a 1.99 GHZ Phenom processor, on an asus M3N-HT (can't remember exact model) mobo. My graphics card is a gtx 260 and I've been running everything on a 750w power supply. I have a dual monitor set-up with one 1680x1050 monitor and one 1280 x 1024 monitor. About a week ago, I got a new Asus HD monitor, so now I have a 1920 X 1080 monitor and a 1680 X 1050 monitor. When I plugged the new monitor in, I noticed a lsight drop in performance, but it was to be expected, since I was using much higher resolutions. Anyway, I normally leave my computer on at night, and its never been a problem (especially since my room is freezing anyway). However, upon waking up this morning, I found out that my computer was off. When i tried to turn it on, all the LED's on my case turn on, the HDD light flickers, but the GPU card's fan does not turn on. I figured that it was a problem with the GPU (overheat, fry, whatever) so I disconnected it (removed it ocmpletely) and just plugged in one monitor with a VGA cable into my onboard. Unfortunately, no dice. Still no display, but LED's come on, Mobo power indicator is on, etc. I'm about to go breadboard my computer to try to isolate the issue even further, but I'd appreciate some sage advice.

Its also worth noting that starting a couple days back, I noticed that my PSU fan will whir really fast then slow to a near stop, then spee dup again, then repeat. It owuld do this for 15-20 minutes and then it'd go back to normal.

tl;dr
- Computer Won't Output a Display to my monitor
-GPU fan won't turn on
-LED's, MOBO fans turn on
-Onboard Gfx don't output either
-Peripherals don't seem to be receiving power
a b B Homebuilt system
January 15, 2011 6:28:20 PM

I assume it doesn't POST? Do you have a system speaker attached?
January 15, 2011 6:30:40 PM

Yeah, no POST, just utter darkness >.< and I don't have system speakers, but i believe there are a set integrated or something, because when I initially build the machine a year back, I heard the beeps off the mobo when somethign went wrong. And yeah, there is just silence.
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a b B Homebuilt system
January 15, 2011 7:54:00 PM

Look internally for a speaker connection. If it's not beeping, it's possible the motherboard is on the fritz. It's usually near the front panel goodies, 4 pins, typically red and black wires. Most boards are set to beep one short for a successful POST, and make lots of annoying combinations if something is awry. Try unplugging the PSU, removing the CMOS battery, and hitting the power switch a few times then reassembling. If that doesn't work, your board may be on it's way out :( 
January 15, 2011 8:00:27 PM

I found the speaker connection and borrwed a speaker from my friend and...no sound whatsoever D:
Tried the reassembling and that didn't help either :\
Its sad, I got this mobo only a little over a year ago...Do you think there could be a processor problem?
a b B Homebuilt system
January 15, 2011 9:34:07 PM

Did you try clearing the CMOS? It's surprising how often that works. If your CPU was bad and the board was good, it would give a series of beeps indicating that.
a c 122 B Homebuilt system
a b C Monitor
January 16, 2011 11:10:19 AM

Work systematically 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, 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: 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...

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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