Thank you for taking the time to reply. I actually couldn't find my post after posting it, so apologies for the delay.

I may be incorrect about the "reset" key. There is a lock inside the unit but I am not sure what it is used for. The key that opens the door also have some kind of function when turned to the LEFT (right opens the door). I know there is some kind of action because when I turn it to the left, a light on the main board lights up. Do you happen to be familiar with the KPE pachislo machines?