Disabling annoying Bluetooth dongle LED the hard way

I recently bought a Bluetooth dongle for my wireless keyboard. After lots of measurements, I ended up fixing it to ceiling for optimal signal quality. There was a problem though; the LED. The pulsating blue LED was just too much for me. Or judge yourself, imagine this:

pulsating wildly every night on the ceiling. Not my thing. I could not find anything with google about disabling programmatically the LED, so I went the hard way and removed the entire LED from the dongle myself with soldering iron.This is the thing, Fuj:tech (wat, Fujitek? Fujitech?) BT402B Bluetooth dongle:

I don’t know if the manufacturer has had an accident or so, but the unit is extremely hard-hackable because it is easy to open. The package is nevertheless firm enough to not fall apart by itself. I started by by inserting fingernail to the visible border and prying:

Cover comes off:

“PCB caddy” can be drawn out of the metallic connector housing:

And the PCB itself comes of easily from the caddy:

Locating the LED is a no-brainer:

For curiosity, pictue of PCB backside:

Then the actual removal. It is easiest to just take a blob of soldering tin and dip the LED with it, the push the component away. Here the removed LED is in the sad blob:

It is good policy to clean afterwards to not cause any unwanted short circuits:

Reassembly is also quite easy. Here all parts laid on table:

PCB drops into the caddy:

Flipped everything upside-down for easier reassembly:

Caddy slides back to the connctor housing:

After slide + flipping the things around again the only thing left is to attach the “cap” back:

Final, reassembled product:

Testing, no side-effects encountered and the Bluetooth dongle is finally without annoying blue disco lights:

Update 2021-09-27:

Due to reader’s request, here are some microscope pictures of the unit components:


5 Replies to “Disabling annoying Bluetooth dongle LED the hard way”

  1. Do you know anything about the chipset the device is using? Any deep info about the dongle would be appreciated as I’m looking into using these for security research.

    1. I took a short look around but I could not find it anymore. I moved recently so things may be bit misplaced. I will search a couple of more boxes later.

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