Fruit Machine Chat

The boards where off ebay bought as an untested set of four.

Could anyone provide the order of sequence for both ends of the power lead obviously one end PSU and other end MPU as I took off to clean and not sure of right order

Have tried four different M1A boards still no +12v light on had power supply repaired checked and cleaned all contacts still no +12v light.

Can anybody help or suggest what to try next please?