Power Failed In LG FLATRON W1642S Computer Monitor Due To Burst Capacitors
This monitor belongs to the hospital where I work and was brought to me with the complaint that it went dead suddenly. The IT-Administrator helped me to open and clean the set thoroughly in the hospital itself. I observed that the Power Supply had two burst capacitors.
I brought the panel home along with the PS board and mother board with the key strip for further investigation and rectification.
I replaced these two caps and checked whether the output voltages were coming. It was. So, replaced the rest of the electrolytic caps as well in the PS and did a thorough retouch of the board. Then cleaned the board thoroughly using IPA.
Looked for any man made shorts using my microscope and indeed there was one. The opto-coupler primary pins were shorted!:
Rectified that and reconnected the boards to the panel and applied power. The monitor was found working very well.
Took it to the hospital, where the It-Admin helped me fix it back. It was rechecked and found to be working ok.
Mission accomplished causing the satisfaction to jump into the 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 Maintenance Done In Computer SMPS Lasted For Five Years!
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Anwar Shiekh
May 21, 2022 at 8:31 am
If Su'scon capacitors lasted 5 years, top grade replacements might last 20
* Rubycon
* United Chemi-Con (or Nippon Chemi-Con)
* Nichicon
* Sanyo
* Panasonic
Paris Azis
May 21, 2022 at 1:32 pm
Elna, as well...
Parasuraman S
May 21, 2022 at 10:17 pm
Yes, same what I mentioned on top applies here! Many thanks!
Parasuraman S
May 21, 2022 at 10:16 pm
Many thanks. Some of these caps are not available in the local market. We are forced to buy only what they sell, which of-course will always be based on their margins!
Paris Azis
May 21, 2022 at 1:33 pm
Good job, Parasuraman!
Parasuraman S
May 21, 2022 at 10:17 pm
Many thanks!
Waleed Rishmawi
May 21, 2022 at 3:21 pm
good job my friend and thanks for sharing. have a blessed day
Parasuraman S
May 21, 2022 at 10:18 pm
Many thanks, my dear friend!
Albert van Bemmelen
May 21, 2022 at 4:47 pm
Another well done hospital service Parasuraman! And interesting e-cap quality info in the comments from Paris and Anwar!
Parasuraman S
May 21, 2022 at 10:18 pm
Many thanks!
Babu M S
May 22, 2022 at 12:32 am
Excellent job done sir. Thank you very much for sharing.
Parasuraman S
May 22, 2022 at 6:35 pm
Many thanks, Babu!
Anil Kumar V K
May 23, 2022 at 2:18 pm
Good job sir,Thanks for sharing
Parasuraman S
May 23, 2022 at 10:18 pm
Many thanks, Anil!
Yogesh Panchal
May 23, 2022 at 10:08 pm
Good Job! Sir
Parasuraman Subramanian
May 24, 2022 at 3:14 pm
Many thanks!
Michael Gallegos
May 24, 2022 at 10:57 pm
Great job, glad the monitor could be put back into service for the hospital! Just a couple of questions if I may? What is the IPA cleaning solution you used?The opto-coupler primary pins that were shorted, do you think it came from the factory that way? How did it work before your repair being shorted? Maybe that opto-coupler wasn’t used? -Thanks!
Parasuraman Subramanian
May 25, 2022 at 3:44 pm
IPA is a short form for Isopropyl Alcohol. Shorting happened when I retouched the board. It was a man made mistake. Not a factory design. The optocoupler indeed is the feedback device that helps the regulation of Pulse Width depending on load. Without that the primary switching would reach saturation and fail. Many thanks!