Apple IIe : MMU & IOU Replacements and Full-Socket Motherboard

[Great Hierophant]

1. Has anyone ever made replacements for the two custom chips inside the Apple IIe, the MMU and IOU? These chips incorporate a fair amount of the TTL logic of the older Apple II/II+ machines, but aren't off the shelf parts and replacing them is not as simple as just simply clicking Order on Jameco or Mouser. On the other hand, as these chips are not the most complex VLSI devices ever made, I wonder if someone has not tried to recreate or even extend their capabilities. Also, how about the AY3600 Keyboard Controller?

 

[dorkbert]

Yes, it's called the MEGA II.

 

[mwillegal]

Original Apple IIe's are still pretty affordable. Currently easiest solution is to find parts from donor systems. Making an enhanced system is another story, but most Apple II enhancement projects make use of the the very flexible slot architecture.

regards,
Mike W.

 

[Wayne Stewart]

The two IIe clones I had used a copy of those chips. They didn't likely sell any separately as there wouldn't have been much of a market. Those chips seldom failed.

 

[george]

Those chips seldom failed.

On the contrary, they fail quite often since a lot of their signals are directly connected to the expansion slots. Several clones of these ICs were produced in several countries plus two or three IC manufacturers like AMI produced them for Apple but nothing leaked so far...unfortunately...Does anybody have the schematic of the Franklin Ace 2xxx? These machines were //e compatible and as far as I remember were completely built with TTL standard ICs...

 

[MarkO_]

Rick Auricchio, who rewrote the Apple ][ ROM for the Apple ][e has some photos of the Apple ][e Development System. I wonder if there is any Higher Resolution pictures of the IOU and MMU development board.

MarkO