LCD Monitors

Recently, my “biggest” home project has been acquiring and repairing broken LCD monitors. Most of the time, LCD monitors stop working simply due to some blown capacitors inside, and for me, this is very easy to fix. Because this is a common problem, it has been easy for me to acquire screens like this.  In fact, I now have a total of 3 monitors I’ve repaired myself, along with another display that the panel was physically damaged on the top, and another monitor I couldn’t locate the capacitor causing the problem, but that I plan to convert to LED.

The display on the left is a Norcent that was destined for the trash,
the right is a Philips with a band of damage along the top.

After a couple of years, many LCD monitors present with symptoms of either no backlight, or simply no power. In most of the cases, bad capacitors are to blame. It could be one, two, five… It all depends. But simply replacing them will most likely solve the problem. Below are the three displays, their symptoms, and the fix.

This Norcent is the most recent monitor I’ve fixed (today, actually). It would power on fine for half a second, then the backlight would cut out (the panel remained active). It had two bad capacitors, a 16V 1000uF and a 16V 470uF. I replaced these, and the monitor functions great. Normally monitors I repair end up with slight->loud whines, probably because of using different capacitors (usually physically larger). This monitor produces almost no whine, and makes the least noise of all of them.

This monitor had 4 bad caps, however I only replaced 3 because I could only acquire three. I had to make a judgement, about which of the caps required replacement the most, and had to leave one still damaged. This monitor simply didn’t have any backlight. Once replaced, all functions as new!

This LCD monitor didn’t power up at all. Absolutely dead. I replaced 4 capacitors on it, and it lived again.

The true utility of electronics: saving yourself money by trading in your time. Isn’t that how it should be?

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Wednesday, July 28th, 2010 electronics, projects

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