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Possible mobo issue, help?

Last response: in Motherboards
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March 16, 2010 6:48:19 PM

Built my first new PC not too long ago for a friend, did everything correctly the first time around, everything went off without a hitch. So I got the idea to build my own. Same deal so I think--everything's wired correctly, but when I hit the power button, the PSU fan spins one notch and stops, nothing turns on. The LED on the mobo is on for power, I just can't get my PC to do anything.

I went through two power supplies, they both did the exact same thing. Any ideas? Is the mobo fried?

Sorry if this is in the wrong area, new to the forums, but REALLY need some help. :cry: 

More about : mobo issue

March 16, 2010 7:03:16 PM

It does sound like an issue with power getting to the main board. Could it be a jumper? The power supply needs to stay on. maybe "playing around" with a tweaker, try shorting some things together, see if power comes on. good luck.
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a c 108 V Motherboard
March 16, 2010 10:40:24 PM

Hunter,

You may have a short somewhere. Try breadboarding your system. To accomplish this:

1. Remove all connections to the motherboard, but leave the CPU, heatsink, and heatsink fan.
2. Remove the motherboard from the case and then place it on a non-conductive surface (such as cardboard or wood).
3. Connect the PSU (don't forget about the 4/8 pin connector near the CPU)
4. Using a flathead screwdriver, jump the + and - power switch pins on the motherboard to turn it on.

Do the fans spin properly? Did you hear a series of beeps? If not, you may have a dead motherboard. If the two above conditions did happen, proceed.

5. Place ONE RAM module into the motherboard, and turn on motherboard using the screwdriver again.

Did you hear the same series of beeps again? if you did, try a different module and repeat step 5 until you don't hear those beeps or until you've tried all of your RAM.

6. Install the GPU or connect the monitor cable to the motherboard chipset. Turn on the motherboard using the screwdriver again. Do you have a display? If so, continue.

7. Now connect the case power button to the motherboard. Use the power button to turn on the motherboard. Do you still have a display? If not, your front panel board may be shorted. If you do still have a display, continue.

8. Now install your hard drive, and continue to test for display. If after connecting the hard drive you still have a display, continue by adding the rest of your hardware, one piece at a time, until you've either got everything connected and your system is working properly, or until you've found the piece that causes the display to fail.

keep us posted...
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a c 156 V Motherboard
March 17, 2010 4:09:15 AM

Dave-PL said:
... try shorting some things together, see if power comes on. good luck.

:pfff:  That is one of the worst ideas ever. If you don't know what you're doing, if you don't know why you're doing it; then don't do it. :non: 

HunterMag said:
The LED on the mobo is on for power, I just can't get my PC to do anything.

I went through two power supplies, they both did the exact same thing. Any ideas? Is the mobo fried?

That LED being on does not mean much besides the PSU being plugged in to the wall and the PSU switch on the back turned on. It has nothing else to do with the main circuits that power the PC.

System specs, including both power supplies?

Do you have a case (system) speaker so you can hear the beep codes? If not:
http://www.cwc-group.com/casp.html

Our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...

Don't just read over the list. Work through it.

There's a link to my breadboarding thread where I have a paragraph about building and test a PC in stages.
http://www.tomshardware.com/forum/262730-31-breadboardi...

The usual problem with a computer that will not boot is the PSU. Try to borrow a known good PSU. Or better yet, see if you can test your PSU in another working system. If you cannot do that, try to borrow a DMM to measure the voltages. 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. 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.

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.
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March 17, 2010 5:15:57 PM

The motherboard seems to be dead. Three PSUs, one which I RMA'd because I thought it was bad, it's replacement, and a known good power supply. Same result each time. Went through the checklist as well. Sadly, my case did not come with a case speaker. I borrowed one from an old PC, and didn't even get some beeps out of it. I tried the replacement PSU in my other PC, and it booted up just fine.

Everything was wired correctly. I think I'll try putting the motherboard in a new case, just to see. I'd rather not RMA it if it's avoidable, so maybe I'll check to see if the case is maybe damaged in some way.
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