The matrix on the 1xx PBs is actually scanned by a separate Mitsubishi M50740 microcontroller, which then turns it into ADB for the PMU's consumption. Kinda wasteful.
On PowerBooks with the PG&E PMU (Moto 68HC05) the keyboard is a simple matrix and the trackball is a raw quadrature hookup, very similar to the M0100 mouse from the 128/512/Plus. PG&E makes them both appear to the system as ADB devices. This is all Duos, all non-1XX up through at least the G3, and the 150.
Very interesting. I missed the second one while trying the map this. So there is two Mitsubishis ?
There isn't many schematics from theses around but on my PB180, I found one M50753 connected to somewhat to 343-1090-1 (Miscellaneous GLU ?) but it's on the dart board.
Now that makes sense as the keyboard is connected to the interconnect board which is connected to the CPU board. There is nothing on the interconnect board so that should be on the CPU board, maybe ?
Will try to trace the ADB line to see if it goes up the main connector. Do you know where the second microcontroller is located ? I'm probably missing something but I can't see the keyboard matrix lines going down the main board. So it's somewhere in the CPU board. 342S0743-1 ?