The most common event that occurs (requiring a clear) is when you do a battery change and the CMOS gets corrupted. You can’t move beyond the error 61.
If you do a game change you get a 61 error due to a changed game chip. You hold the small white button until you hear a ding. The error becomes a 61-1 you close the door and it clears and the game is ready to play.
When the cmos gets corrupted the 61 becomes a 61-1, then a 61 and (reaper, repeat, repeat) and never goes away.
You can search the forum for 61 loop.
The set chip is needed to activate the bill validator and to set the denomination. Ie how many credits for a buck.
You need to use this after each game change or after using a clear chip.