Unfortunately my Garmin Vivoactive HR got into the water and died. So here it is in pieces… Sadly the Vivoactive is not made for swimming which I forgot because I also have the Garmin Forerunner which is Ok in the water. Otherwise, the Garmin Vivoactive HR is a great watch and very useful. 

remove the button part of Garmin Vivoactive HR
then lift slowly with a soft tool the screen of the Garmin Vivoactive HR

The screen was easy to remove with one of these prying too you can buy on amazon, like the one below (sponsored link). 

Once removed be careful when removing the 2 flat connector of the Garmin Vivoactive HR. Use the same tool. 

Most of the next images are a destructive teardown as some of the connectors were damaged by water and corrosion.

Also the battery was completely flat, 0V due to the water that shorted the circuit.

ONce you remove the EMC shield of the PCB of the Garmin Vivoactive HR you find all sorts of nice circuits. Many from AMTEL. There must be the GPS, Gyro, etc…

 Garmin Vivoactive HR

Nice view of the circuit board of the Garmin Vivoactive HR.

Garmin Vivoactive HR
different views of the Garmin Vivoactive HR
Garmin Vivoactive HR PCB
Battery of the Garmin Vivoactive HR. You can see it is a 200mAh 3.8V Li-ion battery (361-00090-00)

The lipo or Li-ion battery of the Garmin Vivoactive HR

you can see the corrosion in the housing of the Garmin Vivoactive HR

The heartbeat or pulse counter of the garmin Vivoactive HR

The GPS or blue tooth antenna (I am not sure which one) of the Garmin Vivoactive HR

Garmin Vivoactive HR
Garmin Vivoactive HR Battery
Garmin Vivoactive HR
the screen of the Garmin Vivoactive HR back screen
Garmin Vivoactive HR

The screen illumination LED of the Garmin Vivoactive HR

This is the culprit, there is a hole from outside to inside of the watch under the little metal plate of the Garmin Vivoactive HR

Garmin Vivoactive HR
Garmin Vivoactive HR screen

the screen of the Garmin Vivoactive HR