Multiple Faults In LG Hi-Fi System Repaired
This LG Hi-Fi system came in with multiple faults such as no sound, can’t change to other button function, CD not working, FM malfunction and etc. Since there are so many sections were affected, it seems the problem could be due to improper DC supply voltage in the power supply section. The moment the cover was opened I got a bit shock because the mainboard was infected by cockroaches…look at the photo below:
I checked on the power supply output DC voltages and all output were tested good and stable! This means the problem is in the mainboard.
I took the mainboard out and fully washed with chemical and dried it but the problem remained the same. Look at the photo below of a ‘cleaned’ board.
If the power supply DC output voltages were good and so many function in the system been affected this suggest that problem could be in the main IC or the Ram IC (yellow circle).
Since I have extra new Ram IC with me, I replaced it first and see how it goes.
To my surprised all the functions in the system came back to normal again! CD was playing fine, FM have have sound and etc.
Conclusion- Beside the power supply need to be working fine to power up the circuit boards, Ram IC is equally important in making sure all the functions in the system are working good. Assuming after replacement of RAM IC was done and the system still malfunction, I will proceed to focus on the main IC. I believe the cockroaches leftovers had caused problem to the RAM IC. What do you think?
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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