Open Diodes and Dry Solders Found In AOC LCD Monitor
This AOC monitor belongs to the hospital, where I work. The complaint was – ‘dead.’ After opening and cleaning the inside, for which the computer Administrator helped me, I quickly located the fault that the output was zero. On checking two parallel diodes in the PS Board, found both open. Replaced it from old boards lying around and switched on.
But the display came on and went off. The CA (Computer Administrator and not that Chartered Accountant!) had told me that the monitor goes off on its own and sometimes comes on when switched on much later or the next day. This was a clear indication of dry solder, especially in the uController area. So, I retouched the board from PS to Main Board, which took a lot of time and minute work. After cleaning up the board and reconnecting, when I switched on, it was stable. None of the electrolytic capacitors showed ESR out of range. Hence closed the monitor and let it run for a few hours before giving it to the CA.
Satisfaction did not miss to jump into the bag!
HERE ARE A FEW SNAPS OF THE INSIDE FOR REFERENCE
This article was prepared for you by Parasuraman Subramanian from India. He is 69 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 repair article below: