What are specific steps to repair the speaker

Hi,

Here is a link from the Ifixit website which shows you how to dis-assemble (teardown) your Game Boy Colour.

Game Boy Color Teardown

At Step 4 in the teardown, you do not have to drill out the screws, apparently, (take note of the comment at the bottom of the page).

At step 6 in the teardown instructions you can already access the speaker so that you do not have to dis-assemble any further (Step 16 in the teardown link below shows what the speaker looks like).You will need to unsolder the wires from the old speaker (do it at the speaker end not at the circuit board) and solder them on to the replacement speaker. Carefully remove the speaker from its' mount before you unsolder the wires. It will be easier to manage. Also solder on the wires to the new speaker before you remount the speaker.Take note of how the old speaker is placed before you remove it. Install the new speaker the same way. Take a photo if you think that it will help to remind you.

Notes

Keep a container handy to place the screws in as you remove them. Also any other parts that are either removed during dis-assembly or that accidentally come off during the process. You'll be surprised how they can disappear!

I cannot see in the photos in the teardown how the speaker is mounted so you may have to work out how to remove the old speaker. As with everything in electronics, be gentle, most larger components are either held by a screw or a clip of some description. If it is a plastic clip be very careful as you do not want to break it if possible. If it is and you do accidentally break it, you may be able to hold the new speaker in place with a dob of silicon sealer where the clip was - superglue, I've found reacts with a lot of plastics.

Re- assembly should just be a reversal of the dis-assembly procedure.