OK, This is thread resurrection but I've just done this myself and documented the process. Many of the videos and tutorials seemed unnecessarily destructive.
This method involves removing the speakers, cleaning away the gooey rotted horror and replacing the foam.
The only supply I could find for the foam rings (easily) was from Aliexpress, so shipping took a couple of weeks.
Parts list:
1x "SOTAMIA 2Pcs 1 Inch Speaker Foam Folding Ring Speakers Repair Accessories DIY Harman Laptop JBL Speaker Edge Repair"
https://www.aliexpress.com/item/1005004702894828.html
Product name: 1 inch speaker foam edge
Material: foam edge
Outer diameter: 30mm
Ring Outer Diameter: 27mm
Ring inner diameter: 20mm
Inner diameter: 17mm
Remarks: Manual measurement, a little error, actual shooting +/-2mm.
Isopropyl alcohol
PVA based glue (I used fast setting wood glue, because that's what was to hand)
Tools list:
Screwdrivers to disassemble the iMac
(optional) Carpenters awl for releasing the speaker clips
Small paintbrush for glue application
Spudger, or plastic lever tool of some sort
Q-tips
Method:
Disassemble the iMac to this state: https://www.ifixit.com/Teardown/iMac+G3+Model+M5521+Teardown/54877#s119719
To remove the speakers, many videos have you "grab it and wiggle until it comes loose". You don't need to do that, especially given the plastics on these are now getting brittle.
Instead, take your awl, or a long, thin screwdriver and poke through this retaining clip. There's a gap just large enough to reach through between the speaker unit and the iMac case.
While doing this, wiggle (a little) and pull along the horizontal axis away from the DVD drive. The speakers are also fixed down with a bit of adhesive foam, but the real reason they're hard to remove is the plastic clip.
Once the speakers are removed, you can disassemble each further with a philips head screwdriver. The clear silicone can stay, I left mine in place and it sealed the bass unit adequately upon reassembly.
Next you will need to carefully scrape away the vile, rotten, goopy foam from both the speaker and plastic sphere in turn. I used a small screwdriver, plastic scrapting tool, Q-tips and IPA. This took a while; you won't get it perfect, but make it clean enough for the glue to adhere to something solid.
To clean the speakers, I gently levered them away from the magnet - turn a little clockwise and lift. I stuck a Q-tip in there to keep it steady whilst cleaning away the last fo the rotten foam.
Clean all the things. Yuck.
To rebuild the speaker, I left the it in the poked out position used for cleaning. I put a decent layer of PVA on the outside of the inner, and slid the foam over the top. Shockingly, the foam linked above fitted perfectly, with a nice firm seal on the inside of the driver. If you have an iMac likely to need this treatment I'd strongly suggest getting these now, before they are discontinued.
I then, for security, added another decent helping of PVA around the join.
Do this for each speaker. Then let them dry.
Finally, spread a layer of PVA on the outer plastic rim of the speaker unit, remove your spacer and whilst carefully rotating the speaker unit back into place, glue the outside of the foam down. Sorry, it appears I didn't photograph this part.
Let this dry, and then reassemble the speaker units, being careful to make sure the cables are located in the same place they were when you disassembled them - otherwise your silicone seal won't be complete.
Reassembly is the reverse of disassembly
IMO they sound as good as they ever did. It didn't involve any hacking or destruction and was done in a couple of hours.
Now you're ready to go play Heroes 3 on your fixed iMac.
This method involves removing the speakers, cleaning away the gooey rotted horror and replacing the foam.
The only supply I could find for the foam rings (easily) was from Aliexpress, so shipping took a couple of weeks.
Parts list:
1x "SOTAMIA 2Pcs 1 Inch Speaker Foam Folding Ring Speakers Repair Accessories DIY Harman Laptop JBL Speaker Edge Repair"
https://www.aliexpress.com/item/1005004702894828.html
Product name: 1 inch speaker foam edge
Material: foam edge
Outer diameter: 30mm
Ring Outer Diameter: 27mm
Ring inner diameter: 20mm
Inner diameter: 17mm
Remarks: Manual measurement, a little error, actual shooting +/-2mm.
Isopropyl alcohol
PVA based glue (I used fast setting wood glue, because that's what was to hand)
Tools list:
Screwdrivers to disassemble the iMac
(optional) Carpenters awl for releasing the speaker clips
Small paintbrush for glue application
Spudger, or plastic lever tool of some sort
Q-tips
Method:
Disassemble the iMac to this state: https://www.ifixit.com/Teardown/iMac+G3+Model+M5521+Teardown/54877#s119719
To remove the speakers, many videos have you "grab it and wiggle until it comes loose". You don't need to do that, especially given the plastics on these are now getting brittle.
Instead, take your awl, or a long, thin screwdriver and poke through this retaining clip. There's a gap just large enough to reach through between the speaker unit and the iMac case.
While doing this, wiggle (a little) and pull along the horizontal axis away from the DVD drive. The speakers are also fixed down with a bit of adhesive foam, but the real reason they're hard to remove is the plastic clip.
Once the speakers are removed, you can disassemble each further with a philips head screwdriver. The clear silicone can stay, I left mine in place and it sealed the bass unit adequately upon reassembly.
Next you will need to carefully scrape away the vile, rotten, goopy foam from both the speaker and plastic sphere in turn. I used a small screwdriver, plastic scrapting tool, Q-tips and IPA. This took a while; you won't get it perfect, but make it clean enough for the glue to adhere to something solid.
To clean the speakers, I gently levered them away from the magnet - turn a little clockwise and lift. I stuck a Q-tip in there to keep it steady whilst cleaning away the last fo the rotten foam.
Clean all the things. Yuck.
To rebuild the speaker, I left the it in the poked out position used for cleaning. I put a decent layer of PVA on the outside of the inner, and slid the foam over the top. Shockingly, the foam linked above fitted perfectly, with a nice firm seal on the inside of the driver. If you have an iMac likely to need this treatment I'd strongly suggest getting these now, before they are discontinued.
I then, for security, added another decent helping of PVA around the join.
Do this for each speaker. Then let them dry.
Finally, spread a layer of PVA on the outer plastic rim of the speaker unit, remove your spacer and whilst carefully rotating the speaker unit back into place, glue the outside of the foam down. Sorry, it appears I didn't photograph this part.
Let this dry, and then reassemble the speaker units, being careful to make sure the cables are located in the same place they were when you disassembled them - otherwise your silicone seal won't be complete.
Reassembly is the reverse of disassembly
IMO they sound as good as they ever did. It didn't involve any hacking or destruction and was done in a couple of hours.
Now you're ready to go play Heroes 3 on your fixed iMac.
