The button problem is typical. You just need to clean the contacts (button and board inputs), but I don't blame you for just starting a conversion. It's probably easier in the long run. Though I will say don't judge a controller by it's age. I love my 26 year old fanuc OM controller.
There is a KMB1 conversion thread here that you might find useful. It's Mach3, but that should be close enough.
http://www.cnczone.com/forums/hurco/...ersion-25.html