These things must be "secretly programmed" to fail at a certain time. My TSU-3000 has worked flawlessly for almost 4 years. Just quit working out of the blue yesterday. Unresponsive screen, hard buttons still work, etc. Sounds like exactly the same problem.

Luckily we have a great resource here with this forum, so I'm going home tonight to hopefully take it apart, clean the contacts and be back in business!!