Snap On Modis Parts

Just a note to let you know that the thumb button *can* be repaired at your kitchen table with a circuit pen.
BACKGROUND: I have a 1st Gen working Modis but the screen was severely fogged/scratched. I dismantled the cover to wet sand (1000/2000/4000) and polish the screen, which meant I had to remove the thumb button and card from the top half of the Modis (2 screws, one small connector). While I had the thumb button switches in hand, I opted to clean the Y/N contacts and the thumb switch contact pad. The good news was my screen was now as good as new, and the Y/N buttons worked as new, but the thumb scroll was now even more touchy and required a lot of pressure to activate - if it decided to work at all.
After 3-4 trials of disassembly, more cleaning, etc, a quick continuity test to the 5 silver traces on the thumb pad's contacts to the small circuit board revealed 3 of the 5 to be open circuits - not good. My two reasonable choices were to find a used Modis with a decent thumb card, or to try and fix this one. I opted to remove the thumb button switch membrane. The membrane is a thin but strong clear plastic sheet with concentric silver traces beneath the membrane - when you push the thumb button around, you are pressing this membrane at various points onto a graphite pad, thus scrolling the cursor (when it is working well). This plastic membrane is separated from the graphite pad around its outer edge by about 0.010' of rubber and adhesive, essentially forming a thin 'standoff' preventing the stiff membrane from touching the conductive pad until pressed.
To get at the silver traces, you need to take a thin, sharp blade (xacto, or razor blade) and carefully dissect the membrane from the conductive pad around its edge - you are essentially slicing through the tacky glue so the membrane can lift off of the thin rubber standoff. Be careful not to cut the membrane or any of the concentric silver traces. Now, with the membrane upside down on your worktable, check each set of silver contacts, in pairs, to ensure continuity. I found all three of my breaks at the neck of the membrane - that is, where the concentric traces all straighten out and make a 1.5' run for the top edge of the membrane, where they contact the control card.
Using a $20 silver conductive pen from Radio Hack, trace carefully over the existing traces, creating a new conductive path between the concentric traces and the edge of the membrane contact pad area. I let this 1st coat dry overnight, but still had one open trace. I traced a second time, and now it had contact everywhere, including a couple new shorts caused by the ink flattening out as it dried. Quick work with a dull knife scraped off the excess conductive ink, and the pad now had full conductive paths with no shorts. Replace the membrane by aligning it over the standoff and pressing it back in place - it's not hard, there are alignment dots that make this very easy to reinstall correctly.
I reassembled the switches in the Modis top cover, and it's now humming and thumb-navigating like new.
Hope this helps someone out - I looked for weeks for some type of guidance on that thumb switch construction before giving up and taking the plunge myself. Will work to take pics if any interest.