The Atari 6402A motherboard is a mystery in itself. Basically
the system board is slightly wider then the 1200/1400XL computers and almost
also deep as the footprint of the 1200/1400XL. The system
board has all the features of the 1450XLD including the on-board disk drive
controller, and modem. However the interesting
part about this motherboard are the ports and their placement around the
system board. All the connectors are set back into the motherboard
away from the edges. This would mean that they would not have
been able to sit into a case so that the ports would be flush and accessible.
Also notice how all the ports are on all 4 sides and the keyboard and PBI
connectors are located on what is believed to be the front of the system
board. It seems that this motherboard was meant to be
more of an in-house lab test than something that was being slated for production.
Atari was having many problems with the 1450XL daughter cards which contained
the disk drive controller for the system, its possible that this motherboard
may have been a platform for testing of the disk drive controller.
At this point in Atari, Inc's agenda, Atari was focusing on the completion
of the 1450XLD system and was concentrating on its new Next Generation
computer system code named "MICKEY".
Mickey was to be the Atari version of the Amiga computer system prior to
Atari's sale to the Tramiels and Commodore stepping in and buying Amiga
comes the name of the motherboard. Why the designation 6402A?
The CPU is a 6502, so why 6402? Its rather strange and puzzling.
The staff of The Atari Historical Society would be grateful if any ex-Atari
engineers out their who may know something or anything in regards to what
was going on as far as development work on the 1450XLD and this rather
odd 6402A motherboard would please contact us and help fill in the
missing pieces on yet another Atari mystery.