Video Card Problem

Video Card Problem

Is the system power coming on? Can you hear fans turning and drive motors spinning up, see little lights on the front of the CPU case, hear any beeps? We're talking about system power here, not the monitor power. If the system isn't powering up, or if you aren't sure whether or not it is, go to the Power Supply Failure chart now.

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Does anything at all show up on the screen with the monitor power on, or is it just as black as before you powered on the CPU? We aren't demanding any signs of intelligent life in this case, any sign of life will do.

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Assuming the system power comes up, does the monitor power come on? Most monitors have a status LED on the front bezel that should show green, orange, or blinking if the monitor is powered on. You can also hear most monitors power on with a gentle sound, though I can't describe it beyond saying it's the sound of a CRT tube warming up. Make sure the monitor is plugged into a good outlet by testing the outlet with a lamp or any other device that will prove beyond a doubt that the outlet is good. Make sure that the power cord is either permanently attached at the monitor end or that it is seated fully in the socket, since partial cord insertion is the most common failure for monitors with detachable cords.

LCD displays don't make any sound when you turn them on, but they don't have a simple power cord, either. LCD monitors are usually powered by an external transformer, which in turn is powered from a regular AC outlet. If the LCD display doesn't show any signs of life, make sure that the cords into and out of the transformer are fully seated. Some transformers are equipped with a status LED to show when they are operating, though you can also check for live output with a DC voltmeter. The power connection to the LCD display is often awkward to inspect, recessed into the back of the display. The important thing is to make sure it is started correctly, then seated all the way.

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Few things related to computers are more embarrassing than taking your monitor for repair and finding out that the brightness was turned all the way down. This frequently happens with exposed dials when you pick up the computer monitor and move it, though a prankster might also turn down the settings when they're concealed behind a pop-out door right under the screen. Make sure that manual brightness and contrast controls on the monitor are set somewhere in the middle of their range, since it's not always obvious which way is maximum or minimum. If the monitor is alive, turning the brightness and contrast all the way up will often result in the screen lighting up a little. The easiest way to check if the monitor is good is to simply attach it to another working PC.

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If you see nothing but a single underline character blinking on and off, usually in the top left-hand corner of the screen, there's probably a problem with initializing the video adapter. That could be caused by the adapter being improperly seated, the motherboard not initializing the adapter properly, or any other motherboard related failure. Continue with the diagnostic flowchart.

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Most new monitors will display something such as "No signal source," or "Attach video signal," as long as they are healthy, and powered on. These messages should appear even if the PC or video adapter is dead. This is actually one of the more useful innovations in monitor technology, because it offers definitive proof that the computer monitor or LCD display is alive and most likely capable of displaying an image if a video signal was present. Unfortunately, it only proves something by its presence, since older monitors and cheaper models may not display anything at all.

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Make sure the 15 pin video signal cable (3 rows of 5 pins each) is seated squarely on the video port on the back of the video card. The hold-down screws on either side of the connector should be screwed in all the way, but not made up too tight. If the video cable is connected correctly, remove it and inspect the connector for damage.

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Look carefully at the pins in the connector to make sure none of them are at an angle or flattened against the bottom. Note that missing pins in a video cable are the norm, usually the monitor ID pins. It's great if you have a spare video cable and a monitor with a detachable cable, but most monitors have an integrated cable (doesn't detach) and most people don't have a spare anyway. You'll usually have to settle for visual inspection for whether the cable may have been crushed or breached.

If you see that a pin in the connector is bent, you can try to straighten it very slowly with tweezers or fine needle nose pliers. If a pin breaks, you can buy a replacement connector and solder it on with a fine soldering iron and infinite patience. You'll also need a heatshrink gun and tubing if you want to do it right. The last time I did one it took me almost three hours, though I didn't really have the right soldering iron tip.

Video Connector Pinout

1-Red

2-Green

3-Blue

4-Monitor ID (Note: pins for ID bits often not present)

5-Ground

6-Red Return (coax shield)

7-Green Return (coax shield)

8-Blue Return (coax shield)

9 No-Connection

10-Sync Ground

11-Monitor ID

12-Monitor ID

13-Horizontal-Sync

14-Vertical-Sync

15-Monitor ID

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Do you hear a string of beeps? Healthy PCs should beep once or twice when they are turned on and pass their Power On Self Test (POST) routine. While different BIOS manufacturers use different beep codes to identify failures, a repeating string of beeps (three or nine in a row) is a common indicator of video card failure.

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To start troubleshooting the video adapter, check if it's is properly seated. This is an in-the-box check, so make sure you unplug the power cord to the system first. You can usually spot a poorly seated video adapter, especially AGP adapters, as more of the contact edge of the card is out of the socket towards the front of the case than the back. This doesn't apply to motherboards with built-in video. Whether or not the video adapter appears to be seated properly, reseat it. Remove the video adapter hold-down screw, remove the adapter, then reseat it in the slot, pushing down evenly. Be careful that putting the hold-down screw back in doesn't lever the front edge of the video adapter (the end away from the screw) up a fraction of an inch out of the slot, because that's all it takes.

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If reseating the card doesn't clear up the beeps, it's either video adapter failure or RAM on the motherboard. You can power down and try reseating the RAM at this point, without going all the way through the motherboard diagnostics. There used to be beep codes for all sorts of component failures, but most of those components have long since been integrated into the motherboard and can't be replaced if they fail.

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Does the system get as far as showing the BIOS screen and locking up? By BIOS screen, we're talking about the text information or brand-name graphics that appear on the screen in the initial boot stages. A system that freezes up at this point is rarely suffering from a video failure, though a conflict between the video card and another installed adapter is still possible.

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Did you install any new adapters immediately before the video card problem appeared? With the power disconnected, remove any other adapters, one at a time, then reconnect power and attempt to reboot after each removal. Locking up on the BIOS screen is often due to an adapter conflict, but if removing the other adapters doesn't solve the problem, proceed to Motherboard, CPU and RAM Failure.

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Do you get a live screen, or at least move past the BIOS screen, with all the other adapters removed? If so, the problem is either a bad adapter preventing proper operation of the bus or an adapter conflicting with the video card. In either case, you can reinstall the adapters one at a time, powering up after each one, troubleshooting the problem by process of elimination. Don't forget to unplug the system each time before taking any action inside the case.

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If the motherboard is a new upgrade, try the video adapter in another system before trashing it, since it could be a simple incompatibility. If installing a new video adapter doesn't solve your "dead screen" problem, it's probably a motherboard related problem, even though you got to this point without any beep codes. Proceed to Motherboard, CPU and RAM Failure. I just added an illustrated guide for how to replace an AGP video adapter to the site.

Thank you

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