I am beginning restoration of 3 Apple II+ machines. Surprisingly, all 3 had Videx Enhanced II keyboard add-ons installed. You can see in the first photo the board removed (top right of photo) There is a series of pins that connect into the Apple's KB andthe ribbon cable connects into the keyboard socket on the MB. There is a 9 pin D-sub style connector that connects to the Enhanced II's membrane key strip.
What I am interested in understanding is the default configuration of an off-the-shelf Apple II+. The Encoder Discrete Keyboard card in the lower left was found among the boards in the lot of items. Is this the standard board foudn in a default Apple II+? I can see it too has a 16 pin DIP socket for the ribbon cable to connect to the MB and the pins to connect to the keyboard itself? But what is the switch in the upper left of the Encoder board? What would/might the place for a D-Sub server in the board. The Encoder board is Apple branded so my suspitions are it is the original board the Apple II+ used. Is that correct? The second photo is a close up of the Encoder.
The Videx Enhanced II board also replaced the chip seen in the next photo. The replacement is the Videx Lower Case chip. What did it replace? If I wanted to return this machine to off the shelf status, what chip goes there? I have been looking for a hi-res, quality image of an off the shelf Apple II+ but still searching. If you can point me towards one that would be great.
Lastly, I want to learn how to identify the various revisions of Apple II+ MBs. I have Googled to see if there is a definitive guide/reference that helps identify the MB but not much luck. Is there a trick to identifying the revisions? I believe the revisions impacts which chips were used in the respective sockets. Any education in this area is most appreciated.
Thanks everyone. I am have really been enjoying this board and so glad I found this community.