Imac G3 Speaker Replacement

Dissassembly

Begin by flipping the unit upside down, as depicted in figure 1. Remove the plastic cover located at the rear of the unit, by using a flat head screwdriver, or similar prying utensil. Remove the 2 outermost long screws located under this cover, as well as the 2 short screw located at the front of the unit, closest to the monitor. This is detailed in figure 2 and 3 respectively. Continue, by lifting up the main plastic cover, and removing it from the bottom of the computer. This concludes the dissassembly section.

Speaker Removal

The speakers are located in "bubbles", which are circular plastic enclosures located on the front of the unit. The "bubbles" can be detached, by rocking them up and down, whilst applying a constant force away from the computer (Figure 5). Once loose, the speaker cables can be disconnected (Figure 6).

Speaker Replacement

In order to replace the speakers, the "bubble" has to be dissassembled. This can be accomplished by removing the screw and prying the bubble open, as shown in figure 7. The old speaker can now be simply removed, as shown in figure 8. Be sure to retain the cable and dispose of the speakers at a qualified recycler. Most retailers, specialised ewaste collectors or metal dealers should accept these.

Once removed, all remaining residue should be cleaned off the speaker "bubble". Plug the cable from the old speaker into a new 28mm (4ohm) driver. These can be purchased on ebay or aliexpress. Apply a 15cm strip of doublesided tape along the outer edge of the new speaker (Figure 10). Place the speaker into the "bubble" and apply cuts to the double sided tape (Figure 11). Fold the tape over the outer plastic edge of the "bubble" to secure the speaker in place (Figure 12). Ensuring that the speaker has an airtight seal will improve the sound quality. 

Reassembly

Place the top cover onto the speaker "bubble, whilst ensuring that the doublesided tape is trapped inside the cover. Add the top screw and repeat the initial dissasembly process in reverse. The speaker should now operate as intended.