Reconverting from BNC to headphone Jack

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Matias Andina

Aug 3, 2023, 11:46:56 AM8/3/23
to FEDforum
We have a bunch of BNC and a bunch of headphone Jack FEDs and we share them between lab members. It's a minor annoyance, but we are always missing the cable that matches the FED that we want to use. It would be nice to reconvert all our BNC feds to Jack, so that we only use 3.5 mm connectors all the time. Can this be done with the old boards (let's say v6.2 dec 2019) ? Is it just as easy as desoldering the bnc and resoldering this jack or any other jack? Has anybody done this?


Aug 3, 2023, 1:38:16 PM8/3/23
to Matias Andina, FEDforum
Hi Matias!  Electrically, the conversion between the models is straightforward as both the BNC and the 3.5mm jacks connect to Ground and A0.  Mechanically, I think it will be hard to de-solder the BNC jack and get the part you found connected correctly to the PCB - the connection points are small and on v6.2 they are not in the right place for that 3.5mm jack.

Instead I suggest removing the BNC jack and soldering a pigtail female 3.5mm jack (link below) onto pins GND and A0 on the Adalogger board, and then hot gluing the female end in place of the BNC jack.  Does that make sense?  If you do this, you can also confirm the 3.5mm jack works before you remove the BNC connector.

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Matias Andina

Nov 21, 2023, 6:31:13 PM11/21/23
to Lex, FEDforum
Finally circling back to this. I can say that it works as expected. Removing the BNC is the most cumbersome part, but not terrible. You will need a soldering iron that can reach at least 430 C / 800 F.
The pics were too heavy for email so I updated the whole procedure in the Wiki
Serial output works as expected.
I haven't tested mechanical stability, but the gluing looks sturdy and should last a while.

I am also in the middle of other repairs (have been putting them off for a while).
* I had some FEDs with broken ON/Off switches, so I will try to put some pics later. That repair was much easier and it's a 1 dollar part. 
* I have 4 or 4 Addaloggers with broken sd card slots (either the spring is broken or the full part came out). Has anybody tried to fix those? I have been buying new ones since it's a 20 dollar board, but I was wondering if somebody ventured into removing the SD reader and soldering a replacement 


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