The Computer Tutorial may be useful as an introduction to the state of the art in the mid-1980s. Circuit Descriptions provides an overview of the main board, control panels, power supply, and output board. Disassembly covers just that; Diagnostics and Adjustments and Checkout should be useful for those who are repairing a Polaris keyboard. Options deals with memory and EPROM upgrades; and the Parts List "outlines most parts needed to service the Polaris."
Thanks to Steve Grom [21030502] for supplying a copy of the manual.