Older NSM machines use a "service switch" (usually a white or black plunger/lever) to enter programming mode.

On the NSM Galaxy, if you rapidly pressed "A + 9 + 9" and held the "A" button while confirming, the machine would sometimes soft-crash. The logic board would misinterpret the "99" code (non-existent on a 60-disc machine) and enter a debug state. In this state, the following codes worked:

: Older wall-mount models often have a key switch on the left side or back. Turning this key switch was a standard operator "hack" to release free credits for the venue.

The motivations vary: