Need advice for two Fitbit One devices

[penny26]

Got my first Fitbit One for Christmas 2012, and it has been a champ until recently.  The button seems to be stuck in somewhat, and the display randomly starts the timer and cycles through steps, floors etc.  However, it is still tracking accurately, synching correctly to my Windows 10 pc, and is holding a decent charge, although is running down faster than usual (presumably because of the extra display activity).  The display is unreliable, as pressing the button typically initiates the random activity.

Since I really like the One, I purchased a backup in December 2015.  It has been unopened in the box since then.  I opened it today and put it on the charger.  It displays Fitbit 6.60 and the full battery icon when it is on the charger, but nothing if removed.  After reading the posts here, I realized that the battery on the new tracker is likely dead due to not being used for such a long time.

I am thinking that the best course of action would be to attempt a battery replacement on the new tracker, using the instructions on this site, and then use the new tracker in the future.  I also thought about trying to replace the battery on the old one and attempting to fix the button once the device was open.  I don't think it makes sense to replace both batteries at once, as then one would be sitting and slowly wearing out, just like my new in box One did.

Does replacing the battery on the new One sound like the best way to go, or does anyone have any other ideas or suggestions to try first?  How likely is it that the button on the original One could be fixed?  I read some posts on here and it sounded like once the button got pushed in, the tracker was on its way out.  Thank you for any assistance you can offer!

[Williger · Accepted solution]

@penny26 yes. Since your older one still works it would make the most sense to refurbish the new One. This way you avoid downtime and aren't without both Ones should you run into problems installing the batteries. I've replaced batteries in several Ones so let me know if any questions. Replacing the button is easy once the case has been opened, but you'll likely need a new one to replace it with. I just replaced two of them as, fortunately, I had "spare parts" from some dead Ones. You can also try pushing it up with a paper clip or safety pin but it may not be fixable.

Replacing the battery is significantly easier if you skip the instructions in this forum. It has an awkward approach to the case and involves soldering the wires onto old wires. It's easier to slice the case open entirely and solder the new battery directly to the PCB as originally intended. I'd created an easy step-by-step guide to doing this complete with photos but a Fitbit moderator removed it without explanation, so instead of wasting literally hours to have my time destroyed, I'd prefer just answering questions within others' posts until I can recreate it on a separate blog that I control.

Short version of my technique is razor around the edges push in towards the button side (too easy to slice the charging contacts otherwise), pry up, and gently remove the casing. Do this slowly so it doesn't crack. I use a microfiber cloth soaked in 99% isopropyl to remove the remaining residue on the casing and may use the isopropyl on the boards themselves if necessary (I've been known to bathe One PCBs in an ultrasonic). Quickly remove the existing wires, replace the battery (there's enough solder to reattach), make sure it works, then re-seal with B-7000 clamped. 🤓

[penny26]

@Williger thank you for taking the time to reply, and for the thorough explanation and offer of future help!  All are greatly appreciated.  😊

[Williger]

@penny26 you're welcome! 😀 Please let us know what you end up doing. Keep on stepping on!

[penny26]

@Williger I mailed the NIB Fitbit One to my son.  He is going to attempt the battery replacement, using your pictures and instructions.  He has the tools, expertise and confidence that I lack!  🤣  I will let you know how it goes.  Meanwhile the old One is hanging in there so far.

[penny26]

@Williger I got the One back from my son and the replacement battery is working great.  I added it to my account today.  It's a good thing, because my old One gave out Monday.  It served me well for nearly nine years!