I wish someone had explained the Data East buttons when I got my JP:
Pressing Black with the green button 'in' starts diagnostics.
Pressing Black with the green button 'out' starts Audits and Adjustments.
When in a menu, green in/out sets black button to show next or previous menu item when pressed.
Some higher menu items are not shown unless you loop backwards through the list, or extend list is selected.
Start button is used change the value.
Also I keep a handy list of things I change (had to set mine for tourney mode practice, and won every JP game I played at the South Carolina State Championships)
adjutment 49 attract music on/off
adjustment 4 game awards = credit -> Extra ball -> special
adjustment 46 trex eat balls = Yes
adjustment 6 limit extra balls 3 -> 0
adjustment 41 tournament => EXPO (resets audits)
audit 25 = show # of total plays