3000A CLDL - occasionally powers on bad ?

A quick look at Digikey indicates that many, if not all, of the EPM3128 family members are listed as "obsolete." This may not be a good part to be using in a new design, but check with your Intel rep to be sure.

There are many possibilities for erratic CPLD behaviours, but most fall into these three categories:

1. Not using a fully synchronous design structure (e.g. having gated clocks)
2. Not debouncing / registering inputs, especially if they go to multiple places in a design or into state machines.
3. Using the part outside of its limits (e.g., clock frequency, input setup times)
4. Not including a global reset

I hope this is helpful