by nvmos2 » Mon Oct 31, 2022 7:05 am
This is a gimmick to entice slot players to play the machine.
In addition to the regular payouts shown on the award plate, the machine will payout on some combinations not shown and that are usually not winning combinations.
If my memory is correct, the Mills 777 with Mystery Payouts will pay 10 coins on 4 different combinations of Oranges and Melons and/or bars. These combinations are not usually winners that slot players are familiar with, hence the "mystery."
Be advised, if your machine was "restored" by some monkeyjcack, it may have a Mystery Payout award plate but not equipped with the proper reel bundle to support the additional payouts, and will not pay on any "mystery" combinations (not shown on award plate).
It is also possible that some devious operator back in the day may have bugged the mystery payouts to prevent paying in hopes that the player wouldn't notice.