Macintosh Classic II FPU board
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Macintosh Classic II FPU / ROM board

Designed by Joshua Ryan ( and Paralel. Pre-built boards can be purchased from Joshua at


The FPU can be any 68-pin PLCC M68882. If you are using a 40MHz chip, you must move the "Clock Select" jumper to "C".

ROM image operation is documented at

Although the original thread has been purged from 68kmla, it has been archived at

Parts list

All capacitors are 0.1µF non-polarized ... except for a single 4.7µF polarized as marked on the board.

The FPU socket is a 68-pin PLCC, Mouser #517-8468-11B1-RK-TP or similar.

The board connector is an AMP 532955-8, Mouser #571-5-532955-8 or similar. .

The oscillator is a 40MHz standard oscillator, Mouser #520-2200B-400 or similar.

The ROM can be either a MC27160 (2MiB) or M27C322 (4MiB)

Circuit board fabrication details

v4.9 is a four-layer board.

The .pcb file is a DesignSpark board file.

The .zip file contains the Gerbers for PCB fabrication. These work as-is with PCBway.