Second machine i've built, no issues with the first one.
I put everything together as usual and had it ready to boot for the first time; the first turn-on was a partial success...the system was running, fans were working, optical drive was functional, etc... The only issue was the fact that i couldnt get a video signal.
This is where the real issue comes in; because i didnt have any video signal, i did a hard shutdown of the machine (i'm a hardware newb...held down the power button for a few seconds). Now, i cant get it to start for more than a single second before it kicks back off. Fans come on, lights up, shuts back down...did i damage something with the hard shutdown???
Obviously, i'm pulling my hair out after spending on the system, putting it together, nearly have it working, then constantly failing. I've tried the troubleshooting guide here step-by-step and still can't identify my problem...any ideas would be greatly appreciated.
Hm. Probably not a PSU issue, then. Are you plugged directly into the wall (not into a power strip)? Have you unplugged everything and put it all back? That's basically what following the troubleshooting guide entails.
Reset the CMOS by removing the motherboard's battery for a few seconds and putting it back in.
Does the other build have more-or-less compatible parts? If so, it would be fairly easy to switch them out to isolate an issue if checking the connections and resetting the CMOS don't work. I'll go into more detail, if necessary, once you've tried the above (one word: breadboard).
I've unplugged everything, completely disassembling the mobo and all cables, etc...
Per your post, i've reset the cmos
Very strange...after doing this, i had the same issue; however, i held in the power button for a few seconds as i noticed it was powering off the moment i let go. The first time, it still shut off the moment i let go; the second time, and its currently up and running...but back to square one, no video!
This is mysterious. Please try your PSU and monitor with your other build. This will take some serious disassembly, but it could eliminate those as culprits. Try breadboarding, laying your motherboard down on a couple of standoffs on a table so you don't have to mess around with your case.
I know the monitor is still good; I just tested it with one of my laptops and there are no issues there. The faulty build is up and running right now...all fans running (plugged directly into power supply, not to mobo); could it still be the psu?
also, how do i appropriately shut down the machine at this point? Thanks
Yes. I'm thinking case, mobo or PSU. Try disconnecting your power switch and shorting the power button circuit yourself to eliminate a faulty power button. Document the weird power-button behavior now and see if you can recreate it with a manual short.
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 (standby power supply): 5 volts always on. The green wire should also have 5 volts on it. It should go to 0 volts when you press the case power button (this is also a good way to test the power switch and the associated wiring), then back to 5 volts when you release the case power switch. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.
The green wire should be 5 volts whenever the PSU is plugged in and the PSU switch is on. It will drop to about 0 volts when the case switch is pressed and go back to 5 volts after it is released.This will also test the case power switch.
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 (unless you have on board graphics available). In that case, remove any card and connect the monitor cable to the motherboard connector.
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.
I think i'll have to get a system speaker...i grabbed a known working power supply (430 w) from work and hooked it up; same issue, once every ten pushes of the power button will hit enough to get fans and hard drives/disc drives working (can open/close optical drive)...but no visual on the monitor even when this happens. Am i missing something obvious here??
"Try disconnecting your power switch and shorting the power button circuit yourself to eliminate a faulty power button.": I'm not sure how to do this, any further instruction would be appreciated.
The frustration is over...i'm sure this is a huge newb mistake, but i would like confirmation that the following is safe/correct.
I had two four pins from the psu hooked into the cpu power on the mobo...i removed one of the two, pressed the power button, and a perfect start-up occurred; cpu, memory was all there, hard drives/disc drives were all read. shut it down, booted again, same thing...success. Are there any issues with using a single 4 pin connector with the 8 pin cpu power on the mobo??