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LED driver board, orient electric, 7W

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  • eccerr0r
    replied
    check the resistance between drain and GND of the IC, if that is shorted, replace IC. I think when you shorted the plate to mains and killed everything the first time you probably backfed power into the IC and killed it... though do check the diodes D1-D4. I don't think anything else would cause repeated fusing of R1/R2.

    By the sound of the symptoms you probably just had a weak LED to begin with that was causing the flickering...

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  • CapLeaker
    replied
    If R1, R2 and L1 blow up all the time, either your bridge rectifier D1 to D4 is shorted or A1 is shorted. Check them out first. Sure you can take L1 out and solder an and replace R2 with a 1 Ohm resistor (fusible resistor fireproof) or similar.

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  • claws77
    replied
    my bad R1 is a fuse, kind off.

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  • stj
    replied
    the only input filtering is R2 and L1

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  • claws77
    replied
    no, i was working on metal plate, and there was some movement and the live wire touched the plate and near the soldered joint and back plate of LED (heatsink) made a connection. i think.

    R1, R2, L1, and the first LED(only) was blown(open) so i replaced them all only for them be blown again (this time i made sure everything was insulated) maybe something else is shorted too. hope its not the IC.

    Can i not use this LED circuit without input filtering. if i am unable to find the right parts.

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  • stj
    replied
    how?
    is c3 shorted?

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  • claws77
    replied
    i have succesfully blown the input (AC) side of the rectifier.

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  • claws77
    replied
    nothing

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  • stj
    replied
    10uf is better
    and check the diodes
    the fact it's pulsing means it's trying to run.

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  • claws77
    replied
    i have 4.7 uF and 400 V and 10 uF & 63 V

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  • claws77
    replied
    LEDs are fine.
    this is a bypass capacitor so can i replace it with any higher value for capacitance and rated voltage
    the current one on board is 4.7uF and 50V

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  • stj
    replied
    test the leds and replace c4

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  • claws77
    replied
    thanks, how to test if IC is faulty.

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  • stj
    replied
    it's an online buck convertor,
    A1 is a VDR to supress spikes

    R8 is to provide a load if the leds fail so the voltage doesnt spike really high,
    you cant read the inductor with a multimeter
    Last edited by stj; 09-29-2024, 07:57 PM.

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  • claws77
    started a topic LED driver board, orient electric, 7W

    LED driver board, orient electric, 7W

    datasheet= https://www.alldatasheet.com/datashe...C/SIC9753.html
    i have tried to make the schematic similar to typical application
    A1 = varistor
    V_C5 _measured wrt -ve = 57-60V pulsating DC, VDD_measured wrt GND_IC = 12-14, VDD_measured wrt -ve = 60-62V pulsating, V_Drain wrt -ve =309V,
    1. L2 is unknown, how to measure inductance with multimeter?
    2. what is happening after rectification and varistor? what does this IC do? how does it provide constant current ?
    3. R8 36Kohm is to discharge the capacitor C5 100uF only, right?
    4. how to test if this IC is faulty?
    Attached Files
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