When i flip the power switch on the back, the green light on the motherboard lights up. As soon as I hit the power button to turn it on, it fires for like a split second and when I say split, I mean split. All that happens is the fan lights flicker, the cpu cooler fan flickers and the psu fan moves a fraction. Thats it. No boot, no beep...nothing. Now I have the 24 pin power connected as well as the 4 pin one next to the cpu. fans are connected. All the sw power, and hdd light things are correctly plugged in. I have tried moving the ram, using only 1 stick and even removed the gpu. Same thing every time. I am going out of my mind trying to figure this out. I built a computer 4 years ago and had zero issues. Any thoughts....please....
ASUS M4A79XTD EVO AM3 AMD 790X ATX AMD Motherboard
AMD Phenom II X4 965 Black Edition Deneb 3.4GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM3 125W Quad-Core Processor HDZ965FBGMBOX
CORSAIR Enthusiast Series CMPSU-650TX 650W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS Certified Active PFC Compatible with Core i7 Power Supply
A-DATA Gaming Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model AX3U1600GB2G9-2G
ASUS EAH6950/2DI2S/2GD5 Radeon HD 6950 2GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity
Now, I have made sure that all motherboard standoffs are in the correct place and screwed into their respective holes. The 4 pin cpu power is plugged in along with the larger 24 pin. If its a short, what could be the cause? I am going out of my mind trying to figure this out. I don't even know what to RMA if need be. Very frustrating.
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.
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.
Sorry it took a few days to get back on here but I HAVE BEEN ENJOYING MY NEW SETUP TOO MUCH. So I took everyone's advice and yanked out/ unplugged everything but the CPU...she fired up. Put ram back in...she still started....put video card back in...still starting. At this point I'm like wtf, thats pretty much everything. Connect front fan to motherboard....no start. Turns out I accidentally had the fan on the same rail as another device and when I plugged that into the mb it must have said wait a tic, theres more than a fan here and wouldn't allow it to boot. With the gob of wires I didn't catch my error. I couldn't believe I spent like 3 or so hours and it was that. Just goes to show how something so minor can botch everything up. Thanks to all that offered advice.