Disconnect the speaker from the main circuit board.

The antenna (a long white wire) has a fragile solder connection to the main circuit board and care should be taken to not yank upon it.

Loosen the screw and washer inside the back cover by the speaker and unwrap the antenna wire that was pinned underneath. Pull the antenna all the way through so the back cover can be removed.

Alternately, you may simply pull only some of it through so that the wire is slack enough that the solder joint is at no risk.

Caution: The speaker and the buzzer connectors are the same so be careful when reassembling.