I’ve been happily using a Dell LCD monitor for a few years now, but it eventually began doing a bit of an electronic opossum impression, playing dead when I hit the power button. Often I could coax it back to life if I “tried turning it off and on again” by completely switching off the power bar, waiting a minute, and powering it up. However, even that eventually stopped working, and I conceded that the monitor was dead, dead, dead.
At that point, I was resigned to shipping the dead monitor off to the electronics recycling depot in the sky, but a GeekFriend suggested that I first take a look at the power supply. Apparently these monitors are well known for dying when the capacitors go bad, and it’s fairly easy to replace them. With nothing really to lose, I opened it up and took a look:
The power supply circuit board (photo by Roy Wood)
A quick peek at the power supply circuit board and it was obvious that one of the capacitors was, indeed, bulging and likely defective. As capacitors age, the electrolyte breaks down and hydrogen gas is released, causing the metal can to expand and bulge upward. If the pressure becomes great enough, the can will burst, leaking electrolyte all over the circuit board and possibly causing even further damage. In my case, it was just bulging a little and failing to store charge as required.
Bad cap! No donut! (photo by Roy Wood)
Once the bad cap was identified, it was easy to desolder it and get ready to replace it. As you can see, the polarity of the capacitor was clearly marked on the circuit board:
Circuit board with capacitor removed (photo by Roy Wood)
With the bad capacitor removed, it was easy to identify the electrical characteristics and find a suitable replacement. My bad cap was a 1000uF device, rated for 16V. I didn’t have an exact match on hand, but I did have another 1000uF capacitor rated for 20V, which was fine. Soldering the replacement into place was quick and easy.
It's soldering time! (photo by Roy Wood)
Once the bad cap was replaced and the monitor reassembled, it was time for the moment of truth. I held my breath, plugged it in, and hit the power button. Thankfully, rather than an electrolytic bang and cloud of magic smoke, I saw this:
It's alive! (photo by Roy Wood)
I’m pleased to report that surgery was a complete success and the patient is now fully recovered. No more playing possum for this monitor.
Now, is this kind of repair something that every GeekDad reader is going to be comfortable performing? Probably not; however, now that you’re all aware that such a repair is possible, I’m hopeful that you’ll consider passing such hardware along to a friend or organization that is keen on repairing it. After all, reuse is far preferable to recycling or landfill…
[Note: This post, by Roy Wood, originally ran during the week. Please leave your comments on the original.]
