Monday, October 20, 2014

The Power Drain Solution for PC hardware problems

Many years ago, I had the good fortune to buy a nice Dell 19" widescreen LCD monitor from Dell at a great price. I think the monitor I now use is about 8 years old, probably closer to 9, but I can't remember anymore. This monitor has served me well all that time.

It has two inputs, DVI (this cable has white connectors) and VGA (this cable has that familiar blue connector) and can easily be switched between the two. That extra input has helped me numerous times to do repair work on computers for friends, myself and to set up a nice little backup server that I now keep in my closet.

The monitor had been working fine until yesterday, when I noticed a pattern of artifacts across the entire screen. This seemed to happen shortly after I had used the monitor as a big screen for my laptop from work. When I disconnected the laptop, and went back to the DVI input, I saw the artifacts appear on the screen. To be fair, I can't remember exactly when the problem appeared, but that seemed like the most likely event.

I wanted to resolve it then and there, but we had planned to have lunch at our favorite Indian restaurant, so I waited until I got back to work on the problem. At first, I thought the problem was the graphics card, that somehow, there was a grounding problem. See, I had the computer and the monitor hooked up through a power strip that should have cleared any grounding problems. The laptop had a VGA port on the side and I hooked up the monitor to that port while the AC power supply was connected to the laptop, with the power supply connected directly to the wall. That's why I thought there might be a grounding problem.

So I tried what I've always done to reset a computer to, what I like to call, the "ground state". Computers have a number of capacitors on the motherboard. These capacitors retain their charge for some time even after the power is turned off. To discharge the capacitors, I powered off the computer, unplugged the power from the computer and held the power button for about 10 seconds, then reconnected the power to boot the computer. Normally this fixes many issues on a computer. In this case, I didn't get the solution I wanted, but did find that my computer would play Mexican radio through my speakers when the power was disconnected and I pressed the power button.

Long ago, I was working tech support for a large chain of non-profit retirement homes. Someone from San Diego called me to say that his computer would not boot. It only got so far and then presented a blinking cursor, without a DOS prompt. After listening to his description, I suggested that he press the power button and hold it until the computer shut down. Then I told him to unplug the computer and press the power button again for about 10 seconds. Then I asked him to plug the power back in and boot the computer. With relief, he reported to me that his computer was working again.

Windows is like that. Often, Windows will recover from many errors with a reboot, but in this case, a complete power drain on the computer was required to remove anything that remained in memory.

I was sort of worried that the drivers on Linux borked the graphics card, but I was still early in my investigation, so I was open to that possibility. After trying a power drain on my computer, I still had the artifacts on the screen. So I unplugged everything and took the computer to the kitchen and opened the box to reseat the graphics card.

What does it mean to reseat the graphics card? The graphics card is a very powerful processor for handling the display of graphics on your computer. For example, if you play games on your computer, the graphics card does the work of displaying the animation from the game so that the CPU can focus on running the computer. Often, the graphics card has far greater power than the CPU, but it's dedicated to the function of running the display for your monitor. My graphics card makes light work of displaying a movie on the screen, as an example.

The graphics card is connected to the motherboard by metal tabs at the bottom of the card and a slot on the motherboard. To reseat the graphics card, I simply open the computer, remove the card from the slot and put it back. My computer had been sitting below my desk for more than a year, so I did some cleaning, too. Cleaning the dust out of your computer can help to remove dust bunnies that can cause electrical problems in computers, too.

Then I took it back to my workstation, hooked everything up and turned it on. Unfortunately, even after reseating the graphics card, I still had the same problem. So I connected my other Linux machine, my laptop, to the monitor. Still had the same problem. With the other computer connected, with no display problems, I could eliminate my main computer as the source of the problem and began to focus on the monitor. I had tried power cycling the monitor, but didn't try a complete power drain from it. I had doubts that would work and had already talked to my wife about buying a new monitor. But I thought I should give it a try, anyway.

I disconnected the power from my monitor, pressed the power button for a few seconds to discharge everything, and plugged the power back in. Then I turned the monitor on and found the artifacts gone. The monitor was completely clear of any artifacts. What a relief! Thankfully, the problem cleared.

I'm very pleased to see this. The power disconnection and discharge technique works on my computer and my monitor. I dub this technique, The Power Drain Solution here and now, but it probably goes under another name. I can see how it can be used in computer parlance with a customer. "Try a power drain on the computer and see if that works." Yeah, I like the way that sounds.

Anyway, I told my wife that I got the monitor problem solved and she said I can still buy a new monitor later. I might just do that. I've been watching movies on my computer lately and have found that works very well for me.

This experience buttresses a principle that I have found that can be applied quite often in diagnosing hardware. The principle is that often times, the simplest solution works best. The hard part is finding the solution. But once the solution is found, I can document it for myself and others here. I hope you find this article useful.
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