The invention of the LCD power module has greatly improved the efficiency of repairs, as we no longer have to waste time searching for schematics and components.
For more details, please see my previous article:https://www.jdwx.info/thread-782444-1-1.html
This is a commonly used mid-power five-wire module
However, during use, we often encounter various accidents that lead to module damage. Over time, I have accumulated about ten broken modules. Although the modules only cost around ten yuan, which isn’t very expensive, it’s a pity to just throw them away, and it’s not environmentally friendly, so I thought about whether I could repair them. The manufacturer deliberately ground off the model number of the power IC to avoid imitation, marking it with GACUNKLY. I suspect this 8-pin IC should be a commonly used power chip, but finding it among hundreds or thousands of ICs is not an easy task! First, I confirmed the main pins of the IC: pin 7 is VCC, pin 1 is GND, pin 8 is GATE, and pin 2 is FB. I have more than a hundred common chips sorted out, and after comparing and studying several major series and dozens of circuits, I found nothing, which made me feel like “after a thousand sails, none are the right one.” Then I found that the mc3843b was somewhat similar, so I installed a 3843b, checked all the surrounding resistors and capacitors, and tested it, but it did not start. Continuing to compare the schematics, I found several different pins. So I kept searching, and finally, when I opened the OB2269 schematic, I was pleasantly surprised to find that it completely matched the module IC. After carefully checking the surrounding components of the module and finding nothing wrong, I installed the chip, tested it, and the long-awaited voltage finally appeared! By the way, OB2268, OB2269, DAP02, SG6841, and SG5841 can be directly replaced (circuit diagram attached).
Original text: https://www.jdwx.info/thread-814593-1-1.html
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