Why These Three Capacitors Fail In Many LG FLATRON LED Monitor?
In this article, the newcomers can learn (1) One of the major causes of device going dead (2) How and why a total dry solder patch up is absolutely necessary, especially in Power Supply Board and (3) Reasons for failure. (4) I have also included an easy method to open this type of monitor!
This Monitor belongs to the hospital where I work. The complaint was ‘dead.’ I opened and cleaned the inside of the monitor with the help of my colleague there.
Then carried the display with boards to home for troubleshooting.
I observed that three electrolytic capacitors had bulged in the secondary. So, replaced these and also did dry solder patch up of the board.
Then, when I checked giving power only to the PS Board, the outputs were ok.
Cleaned and lubricated the connectors. Then connected the boards and applied power to see the display gladly. Also seen is the three bulged caps.
Now, the question is why do these caps fail in LG Flatron Monitors? My presumption is that over a period of time, the stability of the control circuit is affected by dry solders (main causes), variation in values of components used especially the ESR of the caps etc. I think then a sudden power surge causes such capacitors to burst. Experts are invited to comment further on this subject.
Easy method to open this type of Monitor:
Place your finger tips of both hands firmly on the top side of the monitor in face up position without downward pressure on the screen so as not to break it at the tips, and lift the frame up. It will pop out of its holding brackets. Gently do the same on the corner sides, if necessary aided by a flat screwdriver inserted into the gap from the side, taking care not to damage the screen panel.
Follow this on all sides until the frame lifts up. Please do not pull it out, without detaching the front control button panel. Otherwise you are likely to damage the connecting strip wire. (Following is a picture of another monitor which I opened)
Mission accomplished with satisfaction getting added to its collection bag!
This article was prepared for you by Parasuraman Subramanian from India. He is 72 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.
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You may check on his previous article on Beware Of These Fake PWM ICS