Introduction: Repairing LCD Monitor: How NOT to Become Planned Obsolescence Victim

About: Cyclist, hand made knives enthusiast and cnc fan!

Probably anyone, who are interested in technology heard something about "planned obsolescence". There are some descriptions, how to understand this term, but my favourite is the first one popularized. In 1954, engineer Brooks Stevens said that planned obsolescence is "Instilling in the buyer the desire to own something a little newer, a little better, a little sooner than is necessary."
This time we will try to fight against planned malfunctions, by bringing back to life our favourite LCD.

Step 1: LCD Tango Down

In my case, LCD could not establish connection with graphic card. Monitor resets after catching correct video signal. It has been lasting 15-40min; and then, after one of resets, LCD catches signal and works correctly until video signal is present.

Placing heat-sensitive electrolyte capacitor near elements which are emitting a LOT OF energy by heat is one of the most common method to reduce life time of product. This causes faster loose of capacitance and, in effect, failure of element. And this, exactly, happens to me.

Step 2: Disassembling LCD

Detach all of the cables connected to monitor. Put it on flat surface, display down. Remove all screws and stand. Almost all cases are joined together with clips. Using flat screwdriver you have to separate both pieces of casing. Screwdriver should be as parallel to the edge, as possible. Put it in the bottom of panel, in crevice between parts of case. Slowly push it up, till clips releases.
Use your engineer sixth sense to dismantle EMC shields.
When You get to cables, make photo of all connectors, it will be big help in assembling. When photos are done, You can disconnect all connectors.

When cables were disconnected, i could take out box with PCBs. Locating power supply is easy: look for the board with soldered power socket.

Step 3: Looking for Broken Elements

Check all the electrolytic capacitors in supply module, especially the biggest ones and all those, which are placed near radiators or active elements in big packages. Broken capacitor symthomps:
  • convex on the side,
  • convex on the top,
  • woobling of capacitor,
  • something crumbly under the capacitor,
  • some kind of powder on the top.
If near the capacitor is bulge of rubberish thing – it's just glue.
As You can see in the image, two of my capacitors were broken – strange powder on convexed top. Mark the polarisation.
You have to desolder all bad capacitors from PCB.

Step 4: Soldering

Check parameters of desoldered capacitors – capacitance and maximum voltage rating. When You got it, it is time to buy new elements.
The new ones should have same or bigger operating voltage, same or bigger capacitance and should be designed to work properly 105 degree Celsius and should be "LOW E.S.R.". This parameter means that capacitor will work well longer than older ones. Solder capacitors to the board.

Assemble monitor.

Connect power cable, turn power on. If there wasn't any fireworks, try to connect it to the graphic card.


Step 5: System Is Defeated

Using 1-2$ parts, I have repaired my LCD. Sounds much better than spending a few hundreds for another monitor., huh?

Now take your brand new iPhone, look at it. Ask yourself a question "do i really need it?". And remember the definition of Planned Obsolescence... ;)

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