I learned yesterday that my Send button broke at some point in the recent past (I never use it), and instead of doing the smart thing and sending it in, I attempted a repair. Dog barked just at the right moment and I ended up slicing the original membrane with an X-Acto knife.
So ... rather than stop there, why the heck not, I already screwed my warranty, so I opted for a gung-ho repair. Based on a previous poster's repair, I grabbed my tube of "Permanently Flexible" GE Silicone Household Glue, and old SD card case, and went to work.
I removed the original membrane and POS plastic disc. Then, I cut out a very small piece of that old clear plastic SD card case that fit comfortably in the button cavity. Using a jeweler's screwdriver as a tiny spatula, I applied the flexible glue around the inside edge of cavity, careful not to get any on the contact itself, but still having enough to hold the plastic piece. I set the clear plastic into the glue, using a knife to ensure it was centered where I wanted it and dabbed a little more glue where necessary. Waited about 5 minutes. I put a very small amount of glue on the back of the button and set that in place. A USB hard drive provided just the right amount of weight to "clamp" the button and make sure it stays level with the other buttons.
2.5 hours later, I gave it a try. IT WORKS! Using clear plastic and clear glue, the LED light shines through perfectly, and while the button doesn't quite "feel" like it should, probably because the plastic I used is much thicker than the original disc, but it functions. I'm happy enough, since my stupid choice to try and fix it has been, for now, negated
I have to pray I don't lose any more buttons, I actually use the other ones quite a bit. Time will tell how long my repair will last, but I can always clean out the button cavity and try again.
If you're brave and patient and for some reason cannot get a warranty device (or are just a
moron like me and void your warranty thinking it's a 10 second fix), you can seemingly fix these buttons to an acceptable and functional state. Like the previous poster indicated, the most important thing is glue that doesn't fully harden. YMMV, I take absolutely no responsibility if you try to fix your button(s) and screw them up.