Quality scan of the actual service manual, just what I was looking for.
Text excerpt from page 3 (click to view)
Removing the metal cover (See Fig.1)
1. Remove the four screws A attaching the metal cover on the back of the body. 2. Remove the four screws B attaching the metal cover on both sides of the body. 3. Remove the metal cover from the body by lifting the rear part of the cover.
Removing the main board (See Fig.2 to 3)
Prior to performing the following procedure, remove the metal cover. 1. Remove the four screws C attaching the pin jack and the main board. 2. Remove the four screws D attaching the main board.