No video on 2 year old system

Hi All,

2 nights ago my computer was on and I assumed asleep. It wouldn't wake up so I ended up turning it off and turning it back on, only to have no video. The Video card (9600 gt) was making noises like the fan was going out so I assumed it was the video card. I checked the connections, reseated the card, still nothing. So I went out and bought a new video card (5750 HD 1 gig). Plugged it in, fired up the computer and still no video. I checked the monitor and cable on another computer, they are not the problem. All the fans are spinning and the HDD is making HDD noises. I did notice one odd thing. When I power the computer on, it starts up, sounds like it shuts off for about 2 seconds (fans power off) and then starts up again.

Here is what I have done so far based on troubleshooting I have found on the site. My case doesn't have a speaker (or I can't find it) so I couldn't check for beeps:

Checked connections on the new card
Pulled out the ram, new video card, HDD and DVD and added them back in, no changes

Based on what I have read and the little (very little) knowledge I have in these matters I think it may be the power supply. My questions are:

1. am I missing something and it's not the power supply?
2. If it is the power supply, should I just replace it or upgrade to a better one, assuming they even make my current one (Antec Neo Power 500)

Here is my current system:

Antec Three Hundred Black Steel ATX Mid Tower Computer Case
Antec Neo Power 500 500W ATX12V SLI Certified CrossFire Ready Modular Active PFC Power Supply
EVGA 512-P3-N860-TR GeForce 9600 GT 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card (old card, not currently in machine)
radeon 5750 HD 1 gig (new card, in machine)
ASUS P5Q SE PLUS LGA 775 Intel P45 ATX Intel Motherboard
Intel Core 2 Duo E7300 Wolfdale 2.66GHz LGA 775 Dual-Core Processor BX80571E7300
CORSAIR XMS2 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop
Western Digital Caviar Blue WD6400AAKS 640GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive
DVD drive (don't rember the model but it's nothing fancy)
If it were running it wold be running windows 7 ultimate

Any thoughts, help, suggestions, etc would be appreciated.
5 answers Last reply
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  1. isn't the 5750 ati? I could be way off here, but I thought your mobo either supported nVidia or ati. If so, then I'd say that's the issue. But there are a lot more knowledgeable people on here than me.
  2. It's definitely not the video card since neither the old nor new one work in your system. I highly suspect a faulty PSU in this instance, especially since the computer starts up and then shuts of when plugged in. I have one that does the exact same thing and runs fine however. It's like the PSU gets a surge and has enough power to quickly turn on but then runs out of power and works fine when you press the On button. I suggest getting a new PSU.
  3. Well, it's not the power supply. Bought a new antec 500 and plugged everything in, still no video, any other thoughts? It also did the same thing where it started, turned off, and started again.
  4. mainboard might have popped a cap....assuming GPU has supplemental power input(s) connected, etc....
  5. Work systematically through our standard checklist and troubleshooting thread:
    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.

    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. You need a system (case) speaker.

    Breadboard - that will help isolate any kind of case problem you might have.

    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.

    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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