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IBM 5170  -  Motherboard Diagrams


IBM's technical reference for the IBM 5170 contains a lot of diagrams.
Following are some motherboard related diagrams that I have created.


RAM bank layout on type 1 motherboard
RAM bank layout on types 2 and 3 motherboard

Reset flow

Clock generation

Relationship between CPU/NPU internal clocks

BIOS ROM chips U27/U47 - Diagram 1
BIOS ROM chips U27/U47 - Diagram 2

Keyboard controller chip      ( photo )

A20 gate

RTC operation via battery

Shunt block U131

Generation of signal for CE pin on U27 and U47 ROMs

Data buses (simplified)

NMI enabled or disabled