IBM 705 Drawings

Here are some drawings for an IBM 705 system. Most are from the IBM 757 printer controller, one of the three I/O units I have complete drawings for.

These are large black-and-white GIF files. Most are about 2500x3000. They were scanned at 300 DPI.

Toggle Circuit

Sheet 1 The standard toggle circuit.
Sheet 2 Some input gates.
Sheet 3 More input gates.
Sheet 4 Negative shift input gate.

Cathode Follower

Sheet 1 The standard cathode follower circuit.
Sheet 2 Clamp used with trigger circuit.

Sample module

This is a sample module containing the 10's and 100's positions of the "buffer counter", which keeps track of the print position. There are 120 print positions on a 717 printer.

Logic Diagram Logic diagram of the whole buffer counter.

Power Supply

This is from the 705 Central Processor drawings, volume 6. (I have only volumes 2 and 6.) It shows the +140 power supply. Most of the supplies are similar.

Sheet 1 Supply section. Uses a saturable core reactor to regulate the incoming 3-phase before rectification.
Sheet 2 Control section. Amplifies the difference between the output voltage and a reference and generates the bias current for the saturable core reactor.

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