The above should work, see below for Hang On.
https://forums.arcade-museum.com/threads/smarty-pi-hang-on-dip-switch-settings-how-do-you-change-them.557352/#post-5034943
p
The DEV test writes to RAM and checks it, it’s possible that some area of the RAM is bad, I guess you will need to play a game to check it out. Or, change with a known good one and see if it passes.
Good job on figuring the issues out!
p