Quoted from BJM-Maxx:The Alltek has all the game ROMs onboard, you select the one you want with DIP switches, makes it easy to move between games. The Weebly uses the original game ROMs, you need to swap chips if you switch games.
The NVRW MPU uses a single combo ROM with all the game software selected by dip switch
https://nvram.weebly.com/new-pcbs.html