Dell 4550 monitor brightens/darkens - tower overheating?

By jeri
Aug 10, 2009
  1. Hi everyone

    I'm new here and have read over some of the posts and stickies but have not found my issue.

    I have a Dell 4550, Pentium (R)4 CPU, 2.4 GHz and 2 GB RAM (extra added by me). I have never gotten any kind of warning or message that my tower fan was not working properly.

    For the last couple of weeks, I have noticed my computer monitor brightening (a lot) and then darkening (screen is still readable), and then going back to normal. This will happen anywhere from 2 to 6 times in a two hour period.

    I have been turning off the computer when not in use, giving it a chance to cool down, which I now realize was the worst thing to do.

    Today, when I went to fire it up for about the third time, during the start-up, Windows shut down "to protect itself" and gave me a blue screen message to turn off the computer and restart. I did, and have not had that issue again today.

    I have placed a large fan behind the tower and the problem seems to have stopped for now, which leads me to believe the problem is caused by overheating. The tower casing was cleaned inside around 3 months ago, but was very dusty. My questions:

    Does this sound like a tower fan problem and how do I check that it is working properly?

    Are there capacitors or something else I should be checking for heat damage and replacing?

    I know I really just need a new computer, but that won't be happening for a while, so any help you could give me to keep this one sputtering along would be greatly appreciated. Thanks much!
  2. vnf4ultra

    vnf4ultra TechSpot Paladin Posts: 1,388

    Hi Jeri, welcome to TS. I'm not sure specifically about the 4550, but I know most Dells will post a warning on boot if the fan isn't working properly. If you haven't seen the message, it's probably not the fan.

    If you're up to it (which it sounds like you are if you upgraded the ram yourself), open it up and look if the fan is spinning while the computer's running and also while you're in there dust out the computer, especially the cpu cooler and video card heatsink. While cleaning it out, look at the capacitors on the motherboard and/or video card to make sure they aren't leaking or bulging. A cap should be flat on top, it should not be "pointy" or rounded on top or leaking from the top or bottom. I've seen bad caps on a 4550 before, close to the cpu socket (between the rear ports and cpu), so make sure to look to be sure. You may have to remove the green "air duct" to be able to see the caps on the board.

    Also, are you sure the problem is with the computer and not the monitor? It almost sounds like you might be having a problem with the backlighting on the monitor (assuming it's an lcd). Any chance of testing the monitor on another computer to be sure?

    I suppose there's always the possibility of a a failing power supply as well. Sometimes when a power supply is flaky (power fluctuations, noise, etc) it can cause weird issues like BSODs among other things. It's possible that your power supply fan could have failed, and if the power supply is overheating it could be acting up.

    Best wishes.
  3. jeri

    jeri TS Rookie Topic Starter

    Hi vnf4ultra

    Thanks so much for taking the time to explain what to look for with the capacitors. I'll crack it open again tomorrow and go over everything with a magnifying glass if I have to. Hopefully it will be something I can pop out and replace myself. If nothing else, I'm sure it could use another careful cleaning.

    I do also have another monitor available that I can hook up to see if that's the problem -- that would almost be too good and easy to be true.

    Thanks again!

  4. jeri

    jeri TS Rookie Topic Starter

    Just to close out this post; you were absolutely right vnf4ultra, it was nothing but the monitor finally starting to give out. It was the original that came with the comp, a big old crt model.

    Oh well, the tower got a good cleaning again, anyway, and I can rest easy knowing the fans are working just fine and all the capacitors look pristine. Thanks again for your help!
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