I bought mine on ebay, and when it arrived it looked as though it had been used in an industrial evironment. It was quite dirty on the outside, many of the buttons were "sticky" in their operation. As I recall, I cleaned the surfaces, then sprayed the buttons with some contact cleaner/lubricant to get the buttons to operate smoothly. Since doing that, mine has operated well, but I don't know if I had the same problem as you.
You might also check Gralab's web site, they have a flat rate recondition service, on the electronic timers, it's 85 USD.
Or, EP Levine in Boston has a used one for sale, at least they did a couple of weeks ago. It looks almost new.