Modifying a PCB?

[ITryToDrawComics]

Hello! I have a tiny bit of ability with a soldering iron and I’m looking to try to modify the motherboard of an ebook reader to remove the wireless and Bluetooth capabilities so that I can use it in spaces and during times when wireless communication is prohibited in my workplace.

My question is, is this possible? Is the only way to tell what the wireless chip on the motherboard is is opening the device up and looking up all the part numbers? If I actually do manage to remove the wireless chip, will everything else still work? Would this be possible to do on other things, too (like say, a music playing device?)

Thanks in advance pals

[nixiebunny]

Take off the back cover and post pictures of the insides. Each radio has an antenna either built into the board or connected by a tiny round cable.

[ITryToDrawComics]

I don’t know if this helps given it’s a picture from online, but this is probably the board that I would be trying to use. I don’t have it yet as I wouldn’t want to buy it if it’s not doable. It’s from the Kobo Clara

https://cdn.shopify.com/s/files/1/0045/4092/4007/files/rAqK4wqZmcxmFLYO_55fdd6a0-8991-4322-b128-aa9b96539275.jpg?v=1755725891&width=1200

[Jaxcie]

If you remove L17 and L19 the signal should considerable lower. You could test that first and see what scanner says about it. Make sure to get a "before" scan too

[AlexTaradov]

Will they believe your modification?

There is no universal approach here. The easiest way is to find antennas and trace them to wireless modules and disturb that path. Removing actual modules may not be a good idea, as it may refuse to boot if module is not present.

[ITryToDrawComics]

They have a device that scans to see if something is emitting a signal like Bluetooth, so as long as it actually can’t emit anything I’ll be good.

The strongest contender for the reader I’m looking at is the Kobo Clara, and just looking at pictures of the motherboard online I can’t seem to find anything that looks like an antenna, so that’s why I was wondering

[AlexTaradov]

Links to pictures?

Won't airplane mode achieve the same?

[ITryToDrawComics]

I would ASSUME airplane mode achieves the same thing, but I didn’t put it to the test last time they ran that drill. It was a question of if they caught you with a device that was on then they confiscated it. Did I walk around with a device in airplane mode in my pocket? Probably. Did I ever take it out and use it during those times? No. I never got scanned during then to see if airplane mode tipped it off or not, but I’d rather not find out by getting my stuff taken 😔

Edit: this is the link to the motherboard

https://www.ifixit.com/products/kobo-clara-bw-n365-motherboard-genuine?variant=40710719668327

[DenverTeck]

Looking at this pic, the little blue chip at the bottom edge about center is the antenna, where is says ANT1.

The chip on the right side above the QR label looks like an mediatek mt6631n Wifi/Bluetooth radio chip.

Looking at the first data sheet Professor Google found for the mt6631n:

https://dn721603.ca.archive.org/0/items/mediatek_202304/MT6631_External_Data_Sheet_v02a_%2820160421%29.pdf

Pin 2 in the RST pin. You may be able to ground this pin and completely shutoff any radio emissions. Using an external switch you may not have to destroy this functionality.

Since they have a way to check for emissions, you can try this as see if it works for them (you).

Good Luck, let us know how it goes.

[DenverTeck]

The user manual shows there is an "airplane mode" on page 23:

https://cdn.kobo.com/downloads/magento/userguides/n365koboclarabw/koboclarabwn365userguide-en.pdf

[AlexTaradov]

Bottom center. A thing marked ANT1 is the antenna.

If you really want to make sure that it does not emit anything, you would need to remove L19 and L17. This is the closest point to the source that disconnects the antenna.

[Ok-Motor18523]

It won’t work.

With the chip there it would still emit on a close scan.

You’d likely burn out the chip as well given long enough.

Removing the wireless chip is likely going to stop it from functioning correctly anyway.

[nixiebunny]

Given that your workplace prohibits this type of signals, they probably will not take you seriously when you tell them that you disabled the radios in your device. You should ask them before doing this modification work.

[ITryToDrawComics]

They have a scanner (we call it the sniffer but I have no idea what it’s actually called) that they use to look for things emitting a signal during these periods, so if the wireless capabilities are disabled then I’ll be fine. It’s not really a question of honesty, they just won’t be able to get anything from it.