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PSU or MOBO problem! pls help

Last response: in Components
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August 19, 2010 12:39:48 AM

IM NEW at custom build. Everything was completed this morning(custom build). I plugged the comp and it turned on but there's nothing on the screen. I took the battery out for 10 mins and tried it again and nope still nothing. So i waited an hour. Now my comp won't boot! I tried the psu on a diff comp and it didn't work so i assume thats the problem. I tried an old psu(200-250 watts) and i put it on my new custom build pc and it didnt boot and i dont see any green light on the back. So i took back that new psu and tried it again and the comp boot up for 1 sec then turn off.

Here are my thoughts

A: Psu problem ?(Powork 600watts yeah i bought it for 20$ and it sucks!! now im gonna buy a psu that has 80+ certified)

B: Not getting enough Power? COMP SPECS:
MOBO: MSI P7N SLI NVIDIA nForce 750i SLI Socket 775
CPU: Intel pentium e2220 2.4ghz(temporary)
graphics: 9400gt/5450 doesn't matter which 1(temporary) Have 4850
Ram: 2gb on 1 stick LOL
1hdd
and a cd drive

C: MOBO was shorted?(that sucks and it was NEW!)

More about : psu mobo problem pls

a b ) Power supply
August 19, 2010 2:51:56 AM

sounds like your PSU has died taking out something else (probably motherboard) with it.
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a b ) Power supply
August 19, 2010 3:39:43 AM

Don't buy Chinaware next time.
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a c 144 ) Power supply
August 19, 2010 5:41:07 AM

Work 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.

Breadboard - that will eliminate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboardi...

The breadboarding thread has a paragraph about how to build and test a PC in stages.

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU. You do have a case speaker installed, right? If not, you really, really need one. If your case or motherboard didn't come with a system speaker, you can buy one here:
http://www.cwc-group.com/casp.html

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.

If no beeps:
At this point, you can sort of check the PSU. Try to borrow a known good PSU. 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...

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 or long single beeps indicate a problem with the memory.

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.

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.
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