MTR90 mkII CPU card - with MTR90mkIII EPROM PB-4ApA
The mkIII CPU card - with one EPROM - work with the mkII machines as follows:
lots 'I thru P' use EPROM PG06011D
lots 'Q and up" use EPROM PG06011E
Note: Units with the EC-101 required different EPROMS !