Xerox Memorywriter 645S

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Xerox Memorywriter 645S


General Info
Release Year 1985
Manufacturer Xerox
Condition Working
Identifiers
Model Number 645S
Technical Specifications
Software Environment Proprietary DOS
CPU 8088
Memory Capacity 64-128k
Memory Type 64k with CPU, Add-in 64k RAM card
Removable Storage 5.25" FDD
Graphics 50Hz Monochrome TTL interlaced
Display Interface MDA-like but not directly compatible
Power Requirements
Input Voltage 120V AC
QR Code
(Click for Asset Tag)


The Xerox Memorywriter 600 Series of typewriters featured multiple different models with varying levels of Word Processing capabilities. At the top of the model line were the 645S and 645E. The 645S shown here features a display capable of working on documents with full asynchronous word processing features. Lower end models likely have a simple buffer shown on an internal display for making minor corrections and possibly the ability to store forms for re-printing.

The Xerox 600 Series uses an unusual backplane design with different add-in cards for features. Different models did not have features like the external CRT or floppy drives and are likely missing these cards. The 645E should also contain a card capable of some kind of networking with other Xerox systems at the time to double as a printer.

I would like to also specifically state, this machine doe not contain a Zilog Z80 of any kind. It's somewhat of an assumption that unusual 1980s machines would use Z80 CPUs and this machine already has multiple general purpose CPUs in it. But none of them are a Z80.

Repairs - Modifications

2024-01

  • Replaced bearings in carriage drive motor after discovering they were no longer smooth
  • Re-lubricated entire cable drive pulley set to allow carriage to move freely
  • Determined correct belt size is 11in x 1/8in for Sugart SA200 floppy drives

Photos

Backplane Cards

Other PCBs

External links