Bluetooth dying

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  • Seems like my Bangle.js 2 is giving up... It's an original Kickstarter watch and yesterday it suddenly wouldn't connect to my phone anymore.

    Turns out that bluetooth is being very flaky... It will intermittently work for a short period but then it'll stop working again and no matter what I do I cannot get it connected again. Even tested on different devices.

    Factory resetting the watch did not help, and even in DFU mode it'll refuse to connect or even show up most of the time. Even managed to semi-brick it even attempting to install the stable v21 release, since something went wrong during flashing and the watch got stuck looping with a bank0 error. Could get into DFU but nothing else. Eventually managed to get it flashed properly again, but no dice on Bluetooth.

    Everything points to the hardware dying, but just figured I'd hop on here and see if there's anything else I can look at. Opening it up is well within my capabilities if that could help...

  • Argh, sorry to hear that. Does pinching the screen hard in the top right corner help at all? Sometimes that makes it work...

    There are two possibilities:

    • The aerial is part of the case, and it connects to the PCB via a little sprung terminal in the top right edge - it's possible that this has lost contact, in which case pinching a bit may clear off corrosion and fix it. Or you could open the case, unscrew the PCB and screw it back and that might fix it.
    • The actual microcontroller has come slightly unsoldered (it's BGA). I'm not sure on what tools you have, but if you have a hotplate and flux then the fix may not be too difficult - but again it requires opening the case, then pulling off the battery - and you can't easily use hot air because you might melt the GPS aerial.

    I think actual microcontroller damage is unlikely so it's probably one of those two things. I guess if it's not usable right now then opening it, taking the PCB out and putting it back is worth a try.

  • I do not have a hotplate (although it's on the shopping/diy list), but maybe this is a great excuse to finally get one (I could get an MHP30 for about the same price I would pay for a new Bangle including shipping and fees). But, since I just tested pinching the top right corner and the watch immediately connected to my phone it sounds like I won't need a hotplate.

    I'm gonna open it up and see what I can do...

  • since I just tested pinching the top right corner and the watch immediately connected to my phone it sounds like I won't need a hotplate.

    Great!

    Those MHP30 are great, but I also bought one of these a while back: https://www.tindie.com/products/c0pperdr­agon/hot-plate/ Sadly he's not selling them any more, but it was surprisingly effective given how cheap it was and I still use it for big things in preference to the MHP30. There might be similar cheap options available

  • Quick update...

    This weekend I opened up the watch and tried fixing things. Not much luck though.

    It seems like the sprung terminal has been making a dimple in the pad connected to the case and doesn't reach it anymore without some pressure on the top of the PCB. I tested various means of making sure it reaches (like putting a thin shim underneath the pad), and I can get it to function for a while but eventually connection is lost again and only pinching the watch makes it connect.

    Could also be that the connector is loose on the PCB, but I saw no signs of that.

    Apart from the above I also made sure everything was clean.

    It's not looking good so far.

  • Argh, that's a shame - although looking at the spring clip on one I have here it should be pretty easy to re-bend the end a little to extend it by 0.5mm or so.

    You could also look at whether you could file a little off one of the mounts so you can get the PCB to sit a little closer

  • That last suggestion sounds like a great idea. I'll give that a go tonight.

  • I'm officially putting this poor watch to rest. I must have broken something with all the testing and fiddling and no matter how I prod and squeeze I can't get Bluetooth connected anymore.

    It was worth a shot though...

  • Seems I sadly have the same problem (only connects when squeezing it together on the upper right corner) with my Kickstarter bangle2. I'll try to open it and see what I can do. Is there some documentation how to open it without breaking something?

  • https://www.espruino.com/Bangle.js2+Disa¬≠ssembly

    I have a 3D-printer, so it was quite easy to control the temperature for softening the glue.

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Bluetooth dying

Posted by Avatar for johan_m_o @johan_m_o

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