Alas, no-one at Eventide knows anything about 3000's, since they are older than most of our people.
But, it is quite likely that your problem is just a bad switch, and replacements are still available.
I would suggest that you find a local tech, and have him check the switch. If it is bad, he may be able to find a replacement, or contact Eventide and we can send you one.
Be aware that it could be more than the switch, in which case you have to send it to someone who can fix it, but hopefully not.