Bangle.js 2 touch screen does not work

[allstone]

Yesterday suddenly my watch stopped responding to touch screen. It would seem it senses "something" and "sometimes". I have managed to reset to the recovery screen only to get this error:

Uncaught Error: I2C Error: Arbitration (start)

I have found and read these threads:
https://github.com/orgs/espruino/discussions/3375
https://github.com/orgs/espruino/discussions/7294
https://github.com/orgs/espruino/discussions/4293
https://github.com/orgs/espruino/discussions/7700

So I have tried:

Bangle.on('drag',print);
Bangle.setLCDTimeout(0);Bangle.setLCDPower(1);Bangle.setGPSPower(1);Bangle.setHRMPower(1);Bangle.setCompassPower(1);Bangle.setBarometerPower(1);
Bangle.setLocked(0);
Bangle.setLocked(1);Bangle.setLocked(0);
Bangle.setLocked(1);
Bangle.on('swipe', print);
Bangle.on('tap', print);
D36.read(); <------- always returns true
E.getBattery();
setInterval(function() { print("Battery: ",E.getBattery()); }, 5000);
Bangle.setLocked(0);
Bangle.touchRd(0xa7); <------- always returns 255

So I managed to drain watch completely (would not turn on) and charge back to 100%. As well as factory reset and recover. And I also downgraded to v24 from v25 firmware. No changes - touch screen does not work.

I have recorded several videos to see whats happening: https://drive.google.com/drive/folders/1ZCy_dhXOc5cKt7jnxOAAJTgCGKyYVC97?usp=drive_link

Anything else I could try.. or is it a hardware issue and the touch is cooked?

[gfwilliams]

Hi - thanks for trying all of that. The fact that it's showing the I2C Error but only when you press implies that the touchscreen is working but it's the communications between it and the Bangle that are broken. The IRQ line would be being asserted but when the Bangle goes to read from the I2C bus it can't find the touchscreen (as evidenced by your touchRd).

I'd be pretty sure that's a hardware issue I'm afraid. It's rare this happens, but usually when it does it's a sign that the inside of the Bangle has got wet somehow and the connections have started to corrode. Could it have got submerged it water recently?

If so it'd be well worth leaving it somewhere warm and dry for a week, and see if that improves matters at all. It might actually be enough to bring it back to life.

Otherwise it might be that there's corrosion on the connector between the touchscreen and the PCB and just re-seating that connector would fix it, however removing the screen is quite a difficult process.

[gfwilliams]

To be honest by the time we've sent a screen to Lithuania and returned it here the postage would come to close to what a half price Bangle would cost. It's hard to know whether the issue is LCD or the PCB though, but I guess it's one or the other.

Yes, EU warranty is 24 months for manufacturing defects, although I believe a lot of manufacturers place the bar for repair/replacement quite high after 12 months. If you're happy to send the old watch body back then we can try and replace the screen here or if that doesn't work get a replacement out to you though?

[allstone]

here the postage would come to close to what a half price Bangle would cost.

postage and customs surely will calculate vat, at least on one said, but could be both custom offices.. We could try return hts codes and temporarily import forms, but still would need to mark repair and replacement costs, So most likely you will have to pay upon receiving. On my end, declaring and providing custom documents here could also cost 20-30eur just for providing documents. So it might get more or less expensive, depending on different factors I guess.

So maybe lets arrange for a replacement.

Otherwise what I've been doing is where a Bangle has broken, if it's not in warranty I've been offering a new one for half price.

Even if its in warranty, I like what youre doing and want to support you, so I dont mind paying half the price anyways. So if you could just arrange a replacement before it got out of hand with the returns, customs or frying any other replacement and whatnot, I think that would be the best way to go in this case. I see only black color is available and black is awesome btw so it can be black :)

[gfwilliams]

Thanks! That's great! Please can you email [email protected] and link this thread and I'll email you back a discount code for the shop. If I'm shipping anyway it won't cost any extra to put in a spare screen too so I'll do that, and then maybe if we're lucky you can recover the old Bangle as well. If not there are still a few things you can use the old Bangle for (remote temperature/pressure sensor, door open sensor, etc) even if the touchscreen doesn't work.

[allstone]

Just wanted to get back and report. So Ive received the new display assembly. I have installed and still exactly the same issue. So it means the issue should be somewhere in the main board anyways, not in display module side.. I am not sure if I can do anything to debug and find issue in the main board though. If you have any suggestions, I can try. I probably will try to see whats on the board. Idk if theres schematics which I could follow to debug it. And I dont know if I can find the issue though too. But I can try at least.

[gfwilliams]

Argh, I'm sorry to hear that. That's extremely surprising though - the "Arbitration (start)" error comes when the data pin (SDA) gets held low (supposedly by the touchscreen) when the Bangle is trying to start sending data to it. That could be because of either a short to ground on that pin on the PCB or some extra resistance somewhere on it - so you could try cleaning off the PCB with isopropyl alcohol.

You could also try uploading a new firmware to the Bangle that just doesn't check the state of the pin at all by adding i2cTouch.timeout=0; to https://github.com/espruino/Espruino/blob/master/libs/banglejs/jswrap_bangle.c#L3695 - but in that case there's no guarantee that you won't just receive all zeros back (if the resistance is too low).