Based on the issue 1 schematic and photos of an issue C board.
The links have the following function:
LK1 - selects 3MHz clock
LK2 - selects 1MHz clock
LK3 - selects 2MHz clock
LK4 - used in conjunction with LK9 to select EPROM configuration
LK5 - selects 2K RAM
LK6 - selects 1K RAM
LK7 - used to configure IC13 for EPROM, for RAM fit towards bus connector
LK8 - used to configure IC13 for EPROM, for RAM fit towards bus connector
LK9 - selects EPROM configuration, see System 5 Handbook Part 2 Section 2 6502A CPU Board [2]
LK10 - selects keyboard interrupt control, normally open
Schematic
Bill Of Materials
Front Panel Drilling
Blank PCB