I recently shipped my computer via UPS as I was moving and needed it immediately for work. I made sure to pad the inside with appropriate cushioning so components wouldn't snap in transit. Upon arrival I plugged my computer in. Strangely, after flipping the power supply switch and pressing a button on the keyboard it powered up with no video. I powered it down and checked the internal connections. I reseated everything and made sure all the power supply connections were properly inserted into the PSU. I turned it on again and booted up but still no video. I tried two different monitors (one DVI, one VGA with a DVI adapter). The more high monitor wouldn't register. The low end Dell monitor said "no video connection". All the components are powering on (CPU fan, motherboard light, case fans, x3 SATA HDD, and 1 DVD-RW).
I took the video card out and blasted it with compressed air. Reseated and powered back on. Still no video.
I don't have an extra PSU or video card and I intend on going to get one or the other tomorrow. However, I was thinking that it could be the house I'm staying in has low voltage or bad wiring preventing the 700W PSU from getting full power? Could that be an issue?
Anyhow, the video card is a 5870 which is notorious for having this issue. Although, I've had it for a year and a month and haven't experienced anything like this before. The PSU is a Seasonic X750.
It sure sounds like a video card issue. If it boots up, it probably isn't the PSU. Can you test the video card in a friend's PC? If it doesn't work, we can be pretty sure it's the GPU. What brand is it? Hopefully still under warranty.....
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.