PDP-6 Circuit Instruction Manual

This manual serves as a circuit-level maintenance guide for the DEC PDP-6 Programmed Data Processor-6. It provides descriptions for all circuits found in the Type 166 Arithmetic Processor, Type 162 Fast Memory, and the control logic for peripheral devices like the Paper Tape Reader, Punch, Teletype, and Card Reader, as well as standard logic for Core Memories Types 161C and 163C. The document categorizes PDP-6 circuits into seven functional groups: Inverters, Diode gates and decoders, Flip-flops, Amplifiers, Delays, Pulse circuits, and Power circuits.

PDP-6 modules operate at different speeds (500 kc, 5 mc, or 10 mc, corresponding to 4000, 1000, and 6000 series respectively), with defined standard pulse widths and signal levels. Power supply connections are standardized across modules. The manual details the operation of various component circuits, including saturating inverters, diode gates (NAND, NOR, Capacitor-Diode), and decoders. It also covers majority logic circuits used in memory protection and relocation.

Flip-flops, the primary storage elements, are described in various configurations (unbuffered, buffered with inverters, push-pull output buffers) and their application in specific modules like memory flip-flops, subroutine cards, counters, and shift registers. Pulse amplifiers are detailed for their role in standardizing signal amplitude and width, with different types dedicated to specific functions like bus control, memory bus transceiving, and indicator driving. Delay modules provide adjustable signal delays, utilizing either delay lines for short intervals or monostable multivibrators for wider ranges. Pulse circuits include pulse generators, which can be triggered by various voltage changes, and crystal-controlled or adjustable clocks that generate pulse trains.

The document also describes the power circuits, including various AC-to-DC power supplies (728, 778, 734 Variable Supply) and power control units (811, 823 SCR, 829 Two-Step, 832 Two-Step, 834/835 One-Step) for managing power to logic and peripheral equipment. Finally, a section on module repair offers guidance for field maintenance, covering recommended tools, module removal and replacement procedures, and troubleshooting techniques for diagnosing and resolving circuit malfunctions.