fix rattling sound

Heat up the lid by leaving the earbud upside down on a hotplate at ~80°C for ~1min. A 3d printers hotbed works well for this.

A heat gun should also work as well.

The earbuds are glued shut.

Put some cloth around the earbud and put it in a vice like shown.

Pliers might work too if you don't have a vice but it's not recommended.

Slowly close the vice until there is a cracking sound or a gap forms in the seam.

Heat up the lid again before continuing.

Separate the 2 halfs using one of the opening picks.

Make sure not to press the pick more then ~1mm into the case to avoid damaging anything on the PCB.

Slowly lift up the outer half after cracking the seal around the whole earbud. Slowly pull them apart as there is some flexible adhesive on 2 internal pegs that takes a bit of time to "give up".

The marked mic cover tends to easily get lost. It's best to take it of and store it with the top half until reassembly.

Try to remove as much of the hard, clear glue on the outside edge to make sure the buds close nicely when reassembling them.

A precision rotary tool with a fine abrasive tip and/or a scalpel works best.

Try to remove as much of the white glue as possible using a scalpel and/or tweezers.

Putting the lid back on the hotplate or a bit of Isopropanol can help softening it.

The PCB is being held by 3 pins on of which is heat staked (the marked one).

Carefully remove it using flush cutters or scalpel.

Carefully lift the PCB.

Separate the battery from the PCB.

Apply super glue on top of the marked chips to stick down the battery.

Put the PCB back in place for a few seconds to give the adhesive time to pin the battery in the right place.

Lift it up again and press the battery softly on to the PCB to maximize the area that the glue can stick to.

The battery often rests again the front plastic pin when assembled.

For additional stability and protection of the battery a bit of flexible adhesive like B7000 can be applied in the marked area.

Put a bit of super glue on the pin that was cut of at the beginning of this guide (green marker) to secure the PCB again.

Optionally put some on the other 2 pins marked in yellow too.