Trying to find replacement fan light.

Discussion in 'Electronics & Electrics' started by Professor Chaos, Oct 21, 2021.

  1. Professor Chaos

    Professor Chaos Member

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    I have Aeratron DC ceiling fans with light kits.
    The original lights are dimmable 3000k 'warm white'.
    I want to change these to 4000k 'white'.
    I've searched to my limits and can't find a direct swap over replacement, so I suspect I will have to replace the led chips in the light assemblies.
    FYI the power pins are 4mm apart which is leading me to task of replacing the actual chips.
    So I now need your help to locate suitable led chips from the zillions that are available.
    I have worked out the led board is divided into four segments of 6 leds each, each fed by its own diode, then wired in parallel.

    So, please help me find replacement 4000k chips :)

    Edit; I've worked out the printing on the board (6b/4c 9v) refers to 6 bulbs / 4 corners / 9volts each.

    fan driver and light.jpg

    fan light.jpg

    Light open.jpg

    fan shaft.jpg
     
    Last edited: Oct 21, 2021
  2. slavewone

    slavewone Member

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    I’ve gone down your rabbit hole waiting for a kid to go to sleep...

    Have you tried searching for a suitable drop in led panel replacement? I tried “4000k round led panel” you might be able to match the diameter and electrics.
     
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  3. OP
    OP
    Professor Chaos

    Professor Chaos Member

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    It's not a fruitful hole is it :)

    I did think of a full replacement disc, but I'm pretty sure the existing one is glued in with heat transfer glue.
    Then again, if i dig it out i can always clean/dremel the shell before gluing in a replacement.
    Hmm, ok, I will go and do some searching for that anyway.
     
  4. Technics

    Technics Member

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    As you say, there are 4 banks with 6 LEDs. All the LEDs are in parallel in each bank and the banks are wired in series so the individual LED packages must contain 3 dies in series for the 9V rating. They are probably OSRAM Duris E or similar. If you can get the board out you can replace the LEDs if you have access to a suitable temperature controlled hot plate. It can also be done with hot air in a pinch. You won't have much luck with just a soldering iron.

    Edit: Some are available here.
    https://au.mouser.com/c/?marcom=123922902
    They look like 2835 packages on your board.
     
    Last edited: Oct 22, 2021
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  5. OP
    OP
    Professor Chaos

    Professor Chaos Member

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    Ahh 3 chips in each, that makes sense.
    I thought I was insane that the four segments were in parallel yet it was fed 36v.
    Many thanks, I now have several avenues to explore.
     
  6. OP
    OP
    Professor Chaos

    Professor Chaos Member

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    Thank you to all.
    Slavewone - I found some new wafers that were almost right, but sadly not close enough.
    Technics - Your link, sheer gold. Many thanks indeed.
    I followed it to the 4000k version that is in stock.
    https://au.mouser.com/ProductDetail...RS1EM-LVL5-XX55-1?qs=DPoM0jnrROXIwYe1jGTcCQ==
    I ordered just a few 'cough'.
    I will have some spares once I've rebuilt the other three lights. About 900 spare..........
    So if anyone wants some, let me know and we'll work out a price.

    We all love pics :)
    The answer to the inevitable question is - Hakko 926 temp controlled iron.


    Unsolder the two lead wires, removing four internal screws gives you the heatsink body and the aluminium wafer.

    1.jpg

    After a 'sufficient' amount of heat from the iron (480c), directly onto the led chip, the chip breaks apart and comes off, then wick to remove the excess solder.

    2.jpg

    Bit of a scrub with flux remover on cotton buds.

    3.jpg

    Install the new 4000k led chips. Told you I have a few spares :p

    4.jpg

    Not the neatest, but considering it's been 30 years since I played with smd, I'm pretty happy with the result.

    5.jpg

    Not sure how well these last two pics will show.
    But from my perspective, the operation is a complete success.

    A before pic of the original 3000k version with it's dimmer at it's lowest.

    3000.jpg

    And a pic of the new 4000k also at the dimmers lowest.

    4000.jpg
     
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  7. Technics

    Technics Member

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    Well I stand corrected. I have a Hakko 936 but I don't think I've ever had it up to top speed.
     
  8. OP
    OP
    Professor Chaos

    Professor Chaos Member

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    LOL.
    Since it's on an aluminium wafer its all about getting enough heat into the wafer as well.
    Like soldering a board with massive copper lands and plains.
    Once you start and have the wafer heated up, do not stop, just keep going while it's still hot.
    I've had 40 odd years playing with electronics and soldering in many different fields.
    Car battery leads with 0 gauge cable on a gas stove, down to automotive computers smd with hot air reflow pencils.
    Understand the enemy then you can work out how best to attack them :)
    That poor Hakko, its around 25 years old and on very rare occasions like this cops an absolute flogging.
    Other than changing worn out tips, it's never missed a beat.
     

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