Xerox 800 Dual Cassette Electronic Typing System
Console Serial Number 528-206808, Block #1, Model #E
Keyboard-Printer Serial Number 530-031275, Block #2, Model #B
Installed 8/9/77
Xerox's first word processor, the 800 Electronic Typing System, was introduced on 7 October 1974, manufactured in Carrolton, Tx, and test marketed in Dallas, Tx. Ours is a model 800-4 with dual cassette drives, and cost $10,300 when new. A magnetic card version was also available. The 800's daisy-wheel prints at a rate of 30 characters per second (350 words-per-minute) at 10-pitch and 12-pitch, or proportional spacing. The printer was made by Diablo, a Xerox company. The printing speed was much faster than the competitive IBM Cassette Selectric Typewriter. Fonts can be changed by replacing the 92-character daisy-wheel element.
Documents are stored on Magnetic Cards, or with our system on Magnetic Cassettes. The Magnetic Cards hold 72 lines of 150 characters, enough for a typical legal document. A Magnetic Cassette holds 25 letter-sized documents.
The system can do Mail-Merge with addresses stored on one Magnetic Card or Magnetic Cassette, and a document stored on the other Magnetic Card or Magnetic Cassette.
It has a 25 character buffer in case the operator can type faster than the system can record or print a document.
The CPU is implemented with a pair of Signetics 74181 4-bit ALU chips, the same as in the Xerox Alto minicomputer.
There is a promotional video from Xerox here:
And a Xerox commercial here:
The Keyboard/Printer has three stepper motors; Daisy-Wheel, Carriage Left/Right, and Paper Feed. There is one circuit board in the back, and two underneath the system. The keyboard was made by Microswitch. The printer was made by Diablo, a Xerox company
This is the Xerox property label on the Keyboard/Printer. There is another one on the chassis, but it is unreadable. Maybe this system was leased?
The Service Record for the Xerox 800-4. It looks like they had a lot of problems with the printer in 1981.
The quartely maintenance record, with nothing filled out.
The inspection labels on the card cage. It looks like Raytheon Wire-Wrapped the Masterite Industries backplane.
The inside of the Xerox 800-4 chassis. The power supply is at the bottom, The two cassette drives are at the top left, and the card cage is in the middle.
Masterite Industries made the sheet metal backplane.
Dual cassette drives. We found new Xerox cassettes on eBay a few weeks ago.
Front Cassette board and interface to the system.
Rear Cassette Board.
Slot 23 Cassette Controller
Slots 22 & 19 Cassette Interface
Slot 21 Cassette Controller
Slot 20 Cassette Controller
Slot 17 Processor
Slot 16 Processor
Slot 15 Processor
Slot 14 Processor
Slot 13 Processor
The two large chips at the top left are Signetics 74181 4-bit slice Arithmetic Logic Units. These and a bunch of support logic chips form an 8-bit CPU.
Slot 11 Processor
The 8x PROMs most likely contain the microcode for the processor
Slot 4 Keyboard/Printer Controller
Slot 3 Keyboard/Printer Interface
Slot 2 Keyboard/Printer Controller
Slot 1 Keyboard/Printer Interface
Most of the PCBs have a Rockwell logo (At the far right) on them. They were likely made by one of Rockwell's PCB companies, but probably not designed or assembled by Rockwell.
The power supply is a linear type. The power transformer at the top left as an extra coil to implement a ferroresonant circuit. This circuit stores energy in the large capacitor at the bottom left, and if there is a dip in the AC power the circuit acts as a very short term UPS.