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HELP! my custom computer wont turn on *little flicker of power from led on the p

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March 24, 2011 10:23:49 PM

i just built this computer, It will not turn on at all...Only time it shows any life is when i turn off the power completely and try to turn it on which it will flicker just like half a second on the PSU..

I just ruled out the PSU because i just bought a new one to check if that was it and did the same thing...(i returned back)

Im still lost tho...

My computer is this
-ASUS M4A87TD EVO AM3 AMD 870 SATA 6Gb/s USB 3.0 ATX AMD Motherboard
-AMD Phenom II X6 1090T Black Edition Thuban 3.2GHz Socket AM3 125W Six-Core Desktop Processor HDT90ZFBGRBOX
-SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
-GIGABYTE GV-R465OC-1GI Radeon HD 4650 1GB 128-bit GDDR2 PCI Express 2.0 x16 HDCP Ready Video Card
-CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model CMZ8GX3M2A1600C9B
-Rosewill Stallion Series RD500-2SB 500W ATX12V v2.2 Power Supply

The front panel cords are in there right spot. I dont think its the PSU because of me checking it with a new one.

Please does anyone have any advice on where to go from here...All Parts are brand new other then my dvd-r drive.


a b B Homebuilt system
March 24, 2011 10:28:34 PM

Look at the top of this page, there's a troubleshooting sticky.
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March 25, 2011 1:04:22 AM

Yeah, pretty much take the motherboard and power supply out of the case and onto the table....

Remove RAM, GPU, and any and every cable from the motherboard....

Then connect ONLY the 24 pin power. Turn on the system and check that the GREEN LED on the motherboard remains steady ON

Then connect the CPU power cable 4 or 8 pin which every your board takes. Turn on the system and check that the GREEN LED on the motherboard remains steady ON

Now add things back ONE-By-One.... testing power each step of the way. If it won't power up, last component added is bad....

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Related resources
March 25, 2011 1:10:36 AM

First thing I would check is the power supply being connected to both the motherboard and the cpu. You should have a main power supply (bundle) that plugs into the motherboard. There is also a 4,6 or 8 pin power supply that powers the CPU. These are usually rectangular and have a black plug. You'll have to double check your motherboard manual to see which one to plug in. Other than that, I would double check the small 2 pin jumpers that come from the front of that case. Make sure those are connected properly.

One thing to note is that the fan for some CPUs takes a couple seconds to start running. But if it doesn't start after 5-10 seconds, shut the PC off and double check the fan power supply to the motherboard. That's all I can think of off the top of my head.

JKramer119 said:
i just built this computer, It will not turn on at all...Only time it shows any life is when i turn off the power completely and try to turn it on which it will flicker just like half a second on the PSU..

I just ruled out the PSU because i just bought a new one to check if that was it and did the same thing...(i returned back)

Im still lost tho...

My computer is this
-ASUS M4A87TD EVO AM3 AMD 870 SATA 6Gb/s USB 3.0 ATX AMD Motherboard
-AMD Phenom II X6 1090T Black Edition Thuban 3.2GHz Socket AM3 125W Six-Core Desktop Processor HDT90ZFBGRBOX
-SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
-GIGABYTE GV-R465OC-1GI Radeon HD 4650 1GB 128-bit GDDR2 PCI Express 2.0 x16 HDCP Ready Video Card
-CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model CMZ8GX3M2A1600C9B
-Rosewill Stallion Series RD500-2SB 500W ATX12V v2.2 Power Supply

The front panel cords are in there right spot. I dont think its the PSU because of me checking it with a new one.

Please does anyone have any advice on where to go from here...All Parts are brand new other then my dvd-r drive.

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a c 122 B Homebuilt system
March 25, 2011 11:32:28 AM

amateur81 said:
There is also a 4,6 or 8 pin power supply that powers the CPU.

4 or 8 pin connector is for CPU power. 6 pin and 6+2 pin connectors are always for PCIe power. Using the wrong one will result in shorting 12 volts to ground because they are wired differently.

jb has the right idea. He just needs to be a little more systematic.

Depending on the brand an size of the PSU's you used for testing, you still could have a power problem.

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.
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.
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