Capacitors Burst And Fuse Blown Found In LG LED Monitor
In this article one can learn (1) Importance of checking all electrolytic capacitors in power failure cases (2) Importance of retouching all points on such boards (3) What is a technician’s moral responsibility
This, once again, was from the hospital where I work and reportedly dead. After cleaning up the inside assisted by my colleague, I carried the display and boards to home for troubleshooting. Found the fuse was blown and couple of capacitors burst in the secondary.
ESRs of caps were out of range too. So, replaced the all caps both in the PS and mother board. Retouched all the points on the board with fresh solder. Checked thoroughly for any more defective components.
Checked the output voltages and found these to be ok. Connected the boards to panel and found the Monitor working very well.
I carried the display back to office and fixed it in its cabinet and allowed it to run for a few hours. It was working very well.
So, another mission accomplished and satisfaction gathered as usual! Here is a picture of the components replaced:
Why did I replace all the electrolytic caps, including that in the mother board? The ESRs were out of range in most of the ECaps. Replacement of all the ECaps and retouching the board with fresh solder will bring back its life and durability, as the Power Supply section would be stable duly supported by the secondary in the mother board.
Filtering will be better and picture clarify would improve. I believe that a technician’s job is not just bringing the device back to life, but to do all that is essential for its failure free functioning. This is a moral responsibility incumbent on all technicians like us.
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 Dry Solder And Dropped Value Of Caps Found In ATX SMPS
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Paris Azis
March 3, 2022 at 8:55 pm
I fully agree with the idea of moral responsibility, Parasuraman, although it seems to be obvious that in general there is lack of personal responsibility in many fields of our modern life and such voices, as yours now, are not heard. Quality in servicing electronics is expensive and we live in “cheap” times...
Parasuraman S
March 4, 2022 at 9:31 am
Yes, I do agree with you. People do not want to spend but expect quality! But I enjoy doing things the right way to the extent possible! That gives me the reward which cannot be gauged by any measure!
ANIL KUMAR V K
March 3, 2022 at 9:07 pm
Excellent work sir,
Parasuraman S
March 4, 2022 at 9:31 am
Many thanks!
Albert van Bemmelen
March 3, 2022 at 9:14 pm
Another excellent job! In these very frequent cases one could start wondering if our ESR testers are still within spec, especially if these circuits carry e-caps too? Just to expect the unexpected to avoid Murphy's law.
Parasuraman S
March 4, 2022 at 9:34 am
Yes, your doubt is very valid! There is that possibility. But I do check the good ones often whenever I notice a drastic change. Many thanks for your comments and observations! I had changed the E-caps in my PeakAtlas once when it broke down.
Waleed Rishmawi
March 3, 2022 at 10:30 pm
very good jon on the repair but it seems a lot of capacitors to be repalced. I agree with Ablert that our ESR meters should be checked to make sure that it is up and running the way it was intended. have a blessed day
Parasuraman S
March 4, 2022 at 9:35 am
Yes, I too agree. I shall check it up one of these days!
Imoudu Onwumah
March 3, 2022 at 10:48 pm
Another good repair.Speaking on moral responsibility in light of doing complete repair work, depends solely if the customer is willing to pay for such quality service.I have a crt tv on deck now which I intend to change all e- caps on board (48 caps),but customer is not willing to pay for such service,so what do I do?, moral responsibility is threaten!!.
Parasuraman S
March 4, 2022 at 9:38 am
We need to educate the customer many times the advantages and benefits of such works. Especially highlight that he may not have to take it again for repair too soon and our reputation will be at stake if it comes back soon. I do that regularly though I have an adamant customer (a close friend of mine too) who refuses to listen, inspite of burning his fingers due to it. Many thanks for your comments!
Anwar Y Shiekh
March 3, 2022 at 11:19 pm
I'm not sure the primary needs to be low ESR as it operates at high voltage and so low current.
Parasuraman S
March 4, 2022 at 9:40 am
My experience is that when an ESR level is way ahead of the standard, the caps would fail soon. Moreover, it will not work with the efficiency it is expected to. That's why I do this regularly, when I have a choice to decide. Many thanks for your comments!
Paris Azis
March 5, 2022 at 4:42 pm
This depends upon the topology of the power supply...The bulk capacitor of a PFC corrected switchmode power supply, must be a low ESR one, while if PFC is missing, there is no such a demand...
Parasuraman S
March 6, 2022 at 10:01 pm
Yes, dear! You are right!
Yogesh Panchal
March 4, 2022 at 7:33 pm
Good Job!Sir
Parasuraman S
March 4, 2022 at 11:19 pm
Many thanks!