Servicing 48 LED Random LED Light
This random running light is one of the products that I deal with in my hobby sales. This was brought to me by a customer after almost an year stating that it was dead. I opened it and after cleaning of cobweb and dirt of dead insects inside, took it up for diagnosis.
On checking with my Analogue Multimeter, I could make out that one resistor was burnt and three LEDs were short. Replaced these. While replacing the LED, we need to follow the R G B written on the board for selecting the correct colour of the LED. Did a thorough retouch of all solder points. Switched on and it worked. As the IC number was not written on the top, I suspected it could be underneath and removed it. It was there on the bottom (one of the cheap Chinese tricks to avoid copying!) You will also notice that the colour code on the resistor is absurd! (I compared the value of the resistor with another new light from my stock and found it to be 33K!)
Looked for datasheet of this IC, but unavailable as expected!
Provided an IC socket and put the IC back.
Assembled the unit back to its original condition and switched on.
These are the components replaced:
So, my satisfaction list lengthened further!
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: