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Custom built computer not running

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June 30, 2011 11:22:01 PM

Custom built computer not running, PSU failing?
im sure i connected everything in the computer correctly. but the thing is...when i turn on my power supply, none of the fans are running, not even the power supply fan. the only thing i see on is the green led light on the motherboard. is there a way i can test whether my power supply is at fault for my computer not running?


i have a
Antec EarthWatts EA-500D Green 500W PSU
AMD Phenom II X4 955 Black Edition
G.SKILL Ripjaws Series 4GB (2 x 2GB)
GeForce GTX 550 Ti
ASUS M5A87 motherboard
SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
Rosewill CHALLENGER Black Gaming ATX Mid Tower Computer Case
SAMSUNG CD/DVD Burner


i have plugged my power supply in both places on the mobo
June 30, 2011 11:35:09 PM

Give this walk-through a shot.

Also make sure the motherboards bios reset jumper is not in the reset position.
July 1, 2011 5:12:00 AM

i went through the walk-through and my computer is in the same state as it was before.
i want to know where my problem is though. if the led standby light on my mother board is on does that mean my PSU isnt the problem? also how do i know if its my processor? i was pretty rough on my processor and bent one of the pins and i bent it back in place though.

i found the CMOS battery on my motherboard but i dont see any jumpers

i turned on the powersupply, and then pressed the button on the computer case. nothing happened after i pressed the button
Related resources
a c 122 B Homebuilt system
a c 144 ) Power supply
July 1, 2011 11:28:39 AM

If you have been through the checklist, try breadboarding the system and build and test it in stages.

The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread.

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.
a b B Homebuilt system
July 1, 2011 12:07:32 PM

Just throwing it out there: you did plug in the power button to the motherboard, and checked that the polarity is right (sometimes that's an issue)?
I'm assuming you did, but don't want something like that to cause you to buy something unecessarily.

Did you try jumping the PSU if you think it's bad? That would be the first thing I'd do if I thought the PSU was the problem.
July 1, 2011 3:48:15 PM

thehappypen said:


i found the CMOS battery on my motherboard but i dont see any jumpers



You need to use your motherboard manual, there is a short section on how to locate the jumper on the MOBO and the procedure to reset CMOS.
!