Brother WP-70

This is another "intelligent typerwiter" computer from late 1980s, this time made by Brother, a Japanese company specialized in printers. These machines were offered with a different regional options in many countries, but they were popular in Germany as the printout quality was good and they allowed to store edited text. Additionally they were cheaper than computers so if you wanted to edit text on something and had no funds to buy a PC, it was the right choice.
The machine has on-ROM software consisting of a word processor, spreadsheet with calculation (123-like formula forms - (A2+A3) etc. ) on demand, software to edit various tables and frames, contact database and calendar. An on-screen calculator can be started any time. The printer, being a high-quality daisy-wheel printer, allowed to print and erase characters using additional eraser tape if the machine was switched to direct "Typewriter" mode. Font could be changed by changing printer wheel. Data from all software can be stored on a floppy disks. And here the problem begins. The floppy format is something very incompatible. It uses Brother's own implementation of a 3.5" disk drive, with GCR recording (so no way to read it in PC using MFM), 38 or 40-track disk, with 12 256-byte sectors on each. Earlier units used 120kB single-sided disks, this one has 240kB. The "filesystem" makes the file use initially two sectors weighting 512 bytes. This format is strange and incompatible, unreadable on any other devices.
With release of WP-100, in Germany LW-100 ca. 1993, Brother started to slowly run away from this format to a conventional PC floppy format. But it was not easy - although Brother indeed advertised a DOS program which could "magically" read older GCR disks, it was never released. I think that indeed there was such program developed by Brother, but because it was using some hack like half-stepping (like Amiga's ADFREAD and Disk2FDI software does), it was too unreliable. So all these LW-70 users when purchased a new model, with LCD screen, ink-jet printer, graphics support and DOS compatibility, had NO WAY to read their previous work!
Additionally, Taiwanese PC clones became cheaper and cheaper, finally making Brother abandon the series. However, especially in Germany, next models were released as LW-line until late 1990s. The last one, model LW-840ic being in fact a small computer, was released in 2002.

Manufacturer

Brother

Origin

Japan/Germany

Year of unit

1992

Year of introduction

???

Type

Text processor

CPU: HD64180 (Z80+MMU)
RAM: 64kB
ROM: 1MB
I/O: Keyboard, amber CRT,
Power: Built-in transformer-based power supply
Additional capabilities: floppy drive for loading and saving results, built-in daisy-wheel printer (typing + correcting features), beeper.

ROM dump

My unit comes from Germany of course. It was used there as a typewriter in office until ca. 2004.

Technical description:
It is powered with a transformer-based linear PSU, which makes voltages for amber CRT display, printer and mainboard.
The mainboard is based on HD64180 microprocessor, being in fact a Z80 with memory managemtn unit built-in. There is also 32kB of static RAM and 64kB of dynamic RAM, probably for buffering and video purposes. The specialized gate array (upD65046GD091) implements most of system logic. There are two 512kB (4MBit) ROMs - one, usually socketed, for system software may be an EPROM, while the other one, soldered in, is a mask-ROM for spell check dictionary. Although the main software is located in EPROM, the dictionary is in ROM. The type of ROM is set with solder pads, the PROM may be Nec upD23C4001E which is not usual - the functions of CE and OE pins are configurable in programming stage and pin 1 is a CE/OE pin too.
In my unit, the pin 1 of the chip was active-high Chip Enable, while pins 22 and 24 were Active Low. This programmable pin 1 is specific to Nec ROMs and is not present in e.g. UMC 23C4001. That's all if you want to mess with its system.
The mainboard looks that it was made very, very cheap way. It's single-sided, with lots of wire bridges, the only SMD chip is the logic array. Although it was planned to access the board from below, it's not possible because the keyboard ribbon cable is too short. This style of making electronics is not characteristic to computers, it's more like a telephone set or cash register - en masse, as cheap as possible, and with lots of units returned from testing.
And about this 3-pin connector on the rear... seriously I have no idea.