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Troubleshooting Dead Hombuilt

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January 14, 2011 5:34:31 AM

So I built a nice rig this last summer. Turned it off at night and one morning I went to turn it on and it just wouldn't start. Specs then a bit about what ive done so far

Intel i7 930
Asus P6X58D-E
Asus ATI Radeon 5850
DDR3 RAM (6 GB)
Corsair SSD F60
Bunch a other HDDs (reg)
Thermallake 750 Watt power supply

So when I played with it a bit I couldnt get anything to budge- the red light was on at the motherboard's onboard power switch, so it had current, but the fans wouldnt spin on when I pressed it. Nothing worked.

I first bought a new power supply and that did nothing. The old one seems fine. I returned the new one. I RMA'ed the motherboard. Asus swapped it out for a new one (new SN). Now it will turn on- fans start up, but I get nothing. Just a black screen, no BIOS chip screens, no SATA load screens, no beeps. I bought a super cheap PCI-E video card, pulled the 5850, and no difference. Same result.

So what is left? Fried CPU? Fried RAM? How can I tell if its either of those and what do I do if it is? They should all be under warranty.
Wouldnt the BIOS load screens still come up even if the CPU + RAM were dead?!?

thanks- I am about a month into this and going insane without a real computer!
a c 122 B Homebuilt system
January 14, 2011 7:00:57 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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January 14, 2011 4:59:04 PM

Is your monitor working?
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January 14, 2011 6:08:30 PM

Thanks, looks like i have work to do.

Yes the monitors work
And I am confident the motherboard works- will have to try it sans cpu and RAM and step up from there.
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January 15, 2011 2:24:02 AM

So after I stripped it all the way down and back up I figured it out: I put the ram in the black rather than blue slots, causing the black screens.

The motherboard had been the source of the real failure, replacing it had worked.
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January 15, 2011 3:20:02 AM

Congrats on figuring it out! Hope you can RMA the motherboard.
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!