A sad day at the office
Today was a sad day at the office, after months of trouble getting started in the morning, a co-worker passed on. My Co-worker led a very busy life, from the time he joined the company in 2006 as a refurb unit, he has worked hard every day.... until he could no longer take the pressure and just blew his top. He was always a good monitor, with a nice 3:4 ratio and both D-Sub and DVI inputs. He is survived by both his partner, Acer wide-screen, and his parent Quad-Core Desktop. He will be greatly missed..... uhh, no, wait, no he wont.
The cause of all his issues
Many of you are familiar with bad electrolytic capacitors that plagued the years between 2001 and 2007 and have probably seen many computers with bulging or leaking caps. Sadly, many monitors were not immune to this, including my Samsung Syncmaster 204B that I use as a secondary monitor at work. For the last few months, my monitor has been having issues turning on, the back light would flicker at times, and would sometimes just stop responding. I knew that it probably needed some new capacitors, but at the time I had to many projects going on at work and hoped it would hang on just long enough... and it almost did. Today we are going to talk about some symptoms of bad capacitors in LCD monitors and how to replace them.
Symptoms of bad capacitors in LCD monitors
There are quite a few symptoms, so I will just cover the most common symptoms. Some of these symptoms can also indicate bad CCFL bulbs.
  • High-pitched whining noises coming from the monitor
  • Backlight working intermittently
  • Backlight flickering
  • Intermittent operation (does not always power on)
  • Monitor controls and screen becoming un-responsive
Things we are going to need
We should make sure we have a few things before proceeding in to the tear down and beyond, they are listed below.
  • Soldering iron with pencil tip
  • A broken LCD monitor
  • Desoldering braid
  • Rosin soldering flux
  • 60/40 solder
  • Q-Tips
  • Rubbing Alcohol
  • Small pair of diagonal cutters
  • Small pair of pliers
  • Screwdriver (both Phillips and flat-head)
  • French Toast, Eggs, and Sausage

The Tear down
Before deciding to order new capacitors or any other parts, we should disassemble the monitor and inspect the PCBs for any burnt, broken, bulging, or leaking components. Some LCD monitors are held together with just screws while others also have parts that snap together. The plastic case on my Samsung snaps together, so I started by separating the case near the top of the screen and then using a flat head screwdriver to go around the edge of the monitor popping the plastic clips as I went. Be careful not to damage or break the plastic clips. After separating the two halves of the case, I disconnected the cable going to the power button from the monitor chassis and began to examining the chassis for any and all screws that I needed to remove, There were four screws on the side of the LCD panel securing it to the chassis and two screws on the backside of the panel connecting the video board to the chassis. After removing these six screws I was able to inspect the front side of the inverter board and noticed two capacitors were leaking and needed to be replace ( marked as 870uf 25Volt ). I removed the cables connecting the inverter board to both the video board and the LCD panel's backlights and then proceeded to remove the four screws holding the board down. After removing the inverter board, I had to remove a plastic cover protecting the underside of the board, this involved removing 4 plastic clips with some pliers. There were no burn marks on the underside of the PCB and everything but the two capacitors looked good on the top of the board so I decided to but and replace the two capacitors.
Edit: I forgot to mention something that Agent24 reminded me to add.... in the words of Agent24 "MAKE SURE YOU BUY HIGH QUALITY LOW-ESR CAPACITORS!!!". Capacitors manufactured by brands such as Capxon tend to fail fairly quickly. I personally suggest using Rubycon caps.

Repairing the LCD monitor
Now that we have our replacement parts and the inverter board removed, lets begin our repairs. Locate the parts you would like to replace and figure out what pads on the bottom relate to these parts. I prefer to take a small amount of soldering flux and dab a little on the pads belonging to the parts being replaced. Next, take your desoldering braid to each of the marked pads one at a time to remove the solder holding the bad parts down. Be careful not to leave heat on the pads for to long or the pads might burn and/or separate from the PCB. After removing all the solder from these pads, carefully remove the bad parts from the board, noting not only what part you removed from each location, but also the part's polarity. Electrolytic caps WILL NOT WORK when installed backwards and will probably end up blowing their tops if installed improperly. Now that all the parts are removed, look over each pad and remove any leftover solder with your desoldering braid. Next, You should insert the leads for the new parts, taking care to make sure the parts are in the correct position and have the correct polarity. You can bend the excess leads sticking out of the bottom of the board slightly to one side or the other to help hold the components in place until they are held down with solder. After all parts are in place, dab a small amount of the soldering flux on each of the pads and begin soldering the new parts in place. After all parts have been soldered down, inspect the board for any shorts. If everything looks good, clean the remaining flux off of the board with Q-Tips and rubbing alcohol. Re-install the inverter board on the chassis and re-assemble the rest of your monitor.

The moment of truth!
After your monitor has been re-assembled, it is now time to give it a test. I suggest that you not only test the monitor, but leave it on for an hour or two to let it burn in. If you find the monitor does not come on, make sure the power cord is connected properly and that any power switches on the back of the monitor are switched on. With any luck, your monitor should be working as good as new again! I know mine is!