I recently purchased two slot machines from an auction. They are 25 cent machines with the name of El Rancho. Bally manufacturing corporation Chicago USA appears on the right side, the following numbers are listed on the metal plate
1091-43
L091-43-40

Can anyone give the history of this machine. I would like to know when it was manufactured, when and were it went into service, when it was taken out of service and what is it's approximate value. Also, I would also like to be able to get the schematics on it.

Thanks in advance

John