Wally Burr, the voice director for the original series cartoon in the 1980s, has apparently had a stroke earlier this year, and is said to have lost his ability to speak, and some body functions.

He was a guest at BotCon in 2004, 2005 (selling his copies of the movie script and storyboards) and 2013.
It says he's 92 now, so he's certainly beating the odds in terms of the average age. I think we have to prepare ourselves for him being the next to go.