Once you make it correctly, you can the the pcb main in all it's glory.

If you not interest in only teardown, and you want to reapir them try to measure the voltage test ponts on the pcb to find out what is wrong, try to test the 5V USB, 3V3 form the Bluetooth IC, 1V8, and Vbatt (Battery voltage).

CSR 8645 Bluetooth IC

Those cables are connections to one RP (Positive Right channel) and RN(Negative Right channel) and the Black (GND of the Battery) and Red (Positive Battery) and blue one for the Fuse Sensor)

LP (Positive Left Channel) and LN (Negative Left Channel)

A SMD Fuse (Test it with a multimeter in Beep Mode to find out if it's good).

EEPROM Memory (in it's heart that saves many audio, words, and commands for the CSR IC, like "Tha bluetut device has cannected saccesfally".

As you can see there's no way back to Assembly this bluetooth earphone, but if you want: For Assembly this device follow the steps in reverse order.