Repairing an LCD TV/Monitor That Has Slowly Stopped Working

by Morteus in Circuits > Electronics

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Repairing an LCD TV/Monitor That Has Slowly Stopped Working

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This guide was written using my 32" LCD HD flat TV with DVD player model: 32MD251D/37, however I had repaired this same problem on a monitor and another TV. The problem is 90% always the same; burned out capacitors on the power board.

Causes of a burned out capacitor
 Leaving device on for extended period of time
 Running the device out of an unstable or damaged outlet

burned out /bad capacitor can be identified by looking for defects stated below
 Bulged appearance
 Domed tops
 Asymmetrical or stretched plastic jacket
 Fluid leaking
 Split vents

Symptoms of defective capacitors may include:
 Excessive noise in audio or video, including 60hz audio hum or rolling bars in video
 Scratchy, distorted, or missing audio
 Low contrast, blurry, or distorted LCD displays
 Intermittent or outright failure

Required Parts:
• Soldering Iron with solder
• Phillips Head screwdrivers
• Flathead screwdrivers
• Sharpie Marker
• (2) Vented axial 1200uF 35v Capacitors - Varies on model/brand of TV

Removing the Backing and H/W Cover

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I have opened many flat screen TV's and monitors and they are all pretty much built the same; outer plastic shell, Circuit board cover, a power and control board and finally LOTS of screws :) 
So remove all of the backing screws there should be around 8 and the IN/OUT bracke
Remove the 8 (could be more or less) screw in back of TV and set aside
With a thin but sturdy device (a Flathead works) split the two parts starting in the corners. 
It takes some small fingers and strength to work of each "pop" joint and prevent "popped" joints from reconnecting
Before removing any screws disconnect any connections to the power board.
Take photos along the project so you know where everything goes and be sure to have all the connection panel screws removed
Now you will be looking at the circuit board cover (shown in image 4-5), go ahead and remove it

Replacing the Damaged Components

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After identifying the problem, in this case two blown capacitors we will need to remove the old and put in the new.
Unsolder the capacitors one at a time being careful not to cross traces; if you have solder sucker or solder rope then use it.
Once you have extracted the first capacitor, insert the new one and be sure to line up + to +.
Repeat for any other damaged components.

Testing and Reassembly

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Place the circuit board back onto its backing and secure it with 2-4 screws
Plug in power cable and TV should light up as if it was brand new; if this happens then Congratulations on your success :)
Once your satisfied go ahead and replace all the inner and outer screws and connections
Pop the back piece on and you are finished