Nokia Lumia 521 – Disassembling procedure – How to replace the Headphone jack

Push the plastic opening tool in between the screen and the back case of the phone.
Pry the top of the phone between the case and screen until they are separated.

Once the cover has been removed,the battery will be visible. Grab theplastic tab and pull it to remove the battery from its place. If there is noplastic tab, use the plastic openingool to pry the battery loose.
After the battery is removed, push the SIM card from the left side with your thumb until it is loose.

Using the Torx T5 screw head, remove all screws. Note that there are two different sized screws.
Five screws are 5 mm long and four are 4 mm long.
Five 5 mm screws.
Four 4 mm screws.

Using a plastic opening tool, pry apart the inner back case apart from the rest of the phone,
starting at the top and prying while going around the phone.

Unclasp the motherboard from the black case clasps using a plastic opening tool.

Unclip the motherboard clasps using your fingers or a plastic opening tool.

Gently pry audio jack with your hand until it is removed from its space on the phone.

Unclasp the golden flap attached to the audio jack using the plastic opening tool (The top golden flap should already be unclasped from removing the motherboard).