Cleaning audiomoth circuit board

Robin Sandfort

@capreolus
| he/him

Capreolus e.U.

wildlife biologist with capreolus.at

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Acoustics

Hi everyone,
unfortunatly I got quite a few audiomoth boards with different levels of water damage.
I removed the battery holder and plan on cleaning the boards. Do you have any experience with this kind
of restoration? Would you use destilled water or Isopropanol for removing the corrosion?
Thanks for your advice.

Greetings from Austria,
Robin

Harold Tay

@htarold

Worked as a mechanical engineer for a defence co, then software engineer, then for a research lab specialising in underwater robotics.

27 January 2023 1:40pm

Hi Robin,

I typically use isopropanol AKA isopropyl alcohol and scrub with a soft toothbrush, then dry with something like kim wipes, then blow dry. In a pinch I've use rubbing alcohol, but that is only 70% alcohol.

After you've repaired the boards, you may want to consider applying a conformal coating.

Thanks

Robin Sandfort

27 January 2023 1:40pm

Thanks for sharing your experience Harold!

Akiba

27 January 2023 1:40pm

I'd also add that if the boards are just dirty or dusty, you can just remove all batteries, then wash with a toothbrush and water. Air dry (or use compressed air which speeds things up greatly) and then spot clean areas that need solvent with isopropanol as Harold mentioned. Also if you don't have access to conformal coating, you can also use a non-conductive clear lacquer. The conformal coating covers all the components and prevents short circuits due to conductive water (ie: salt water) or other contaminants. However if you do use a conformal coating, make sure all cables are connected first and the device is in the exact state that it will be deployed in. Also don't conformal coat the battery connectors since you'll want to change out batteries periodically.

Robin Sandfort

27 January 2023 1:40pm

Hi Akiba,
thanks for your this great advice! I used the conformal coating on parts
of the PCB with exposed metal but was has hesitent using it on the "backside" with
all the resistors and transistors. Also what about the "back" of the microfon. Might this side be coated?
Do you have any experience with coatings @alex_rogers

Greetings,
Robin

Robin Sandfort

27 January 2023 1:40pm

Cleaning the water damaged audiomoth boards is in full swing:

Left before, right after cleaning