i have added more photos to my link

It looks quite good - some elbow grease and a little TLC on the connectors and you might have a goer!

The MPU 'looks' OK butyou really do nead to have a critical (close) inspection of the board for corrosion around the blue battery - corrosion here CAN write the entire board off so better to correct that before doing anything else IMO.

There are some very well known 'issues' with this era of machine (basically it is an early solid state (SS) Bally but most issues are easy to sort out.

You should have an interesting learning experience getting it all sorted - there is a wealth of knowledge on this site and many who will be willing to tell you where to go (in a nice way) for parts etc.