So, I just finished assembling and installing everything in my case and I went to plug it into the monitor to see if it works. When I turn on the monitor it just says VGA no signal and then goes to sleep. I think I may have not plugged in the monitor correctly because there weren't any instructions in it.
So, I just plugged in what cords I thought I should. The cords I plugged in are this white-headed cord that connected the monitor and GPU (I think it's the DVI cable), this green-headed cord that I connected to the audio, and the power cord that I connected to the wall.
One other thing that seemed odd was that when I turned the computer on, the fans and everything ran for about 5 seconds and then stopped. After about another 3 seconds, everything turned back on again and kept running. What is causing this?
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.
Alright, so I have a completely different problem now. I looked at the onboard LEDs and the DRAM LED was lit up, so I pushed on the RAM a bit and discovered it had not been completely installed. I then started it again and it booted!
Filled with happiness, I turned everything off and went to get my copy of Windows 7. When I turned it on this next time, it did not boot. A different LED light lit up. This time the CPU LED was lit.
How could it boot up one time and then 10 minutes later, after not being touched, it failed to boot?
Anyway, I unplugged everything and put the motherboard on the box. I then, reinstalled the heatsink and CPU. Unfortunately, this did not fix the CPU LED.
What should I do? Do I have a faulty motherboard or a faulty CPU? I did not see any thermal paste drip off the CPU or in the socket. I used the pea method.
I temporarily solve this problem by reseting the CMOS. Unfortunately, it will only boot once. After, I turn it off and try to boot it a second time, the CPU LED lights up and everything turns off after about 5 seconds.
I can keep reseting the CMOS, every time to get it to boot again, but I don't understand why my system is so inconsistent.
I have reinstalled everything and made sure it was properly installed.
Is something wrong with my motherboard? Is something wrong with my CPU? If not, any suggestions on how to fix this and make it stay fixed?