Pry lightly around the edge of the main board between the board and the casing to help free the board. Fingernails, a spudger, or plastic opening tools can be used for this task.

DO NOT TRY TO REMOVE THE MAIN BOARD COMPLETELY!!! There are soldered items that need to be dealt with. Follow along closely.

Gently, and I mean gently, pull up on the LED assembly to loosen the main board from the rear casing.

Any resistance should indicate that the board needs to be loosened from the casing, around the edges, more before proceeding.