9 August 2019

The NEC PC-8401 Reexamined: Part 1

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A few years back I came across an NEC PC-8401 and proceeded to write up a number of articles during a Retro Challenge month on the machine. Going by blog statistics since RC2017 ended, the NEC PC-8401 is just about as popular in 2019 as it was in 1984. Which is to say not at all. A sad state of affairs then, unlikely to be remedied by further posts concerning this laptop-esque computer. Still, no harm in trying is there?

NEC PC-8401 with PC-8431A, PC-8441A & PC-8406A Expansions

A quick re-acquaintance With the PC-8401

For those who haven't read previous articles on the subject; the PC-8401 series of computers was one of NEC's attempts at introducing portable computing to the business masses. It's main focus is productivity applications, with Wordstar-To-Go, Calc-To-Go, Filer (card filing program) and telecommunications software built into ROM all spring boarding off a CP/M 2.2 OS core.

On the hardware front the 8401 comes with a Z80A CPU, 64k battery backed static RAM (this is shared between RAM and RAM Disk), a rather splendid mechanical Alps keyboard and a just reasonable 80 column x 16 line reflective LCD display panel. Additionally some versions came with a built in 300 Baud modem (sadly not much use today).

When at home or in the office, the machine is powered externally via a suitable 5v to 9v power brick. But what good is a laptop if you can't use it at the pub? Four C Cell batteries answer this pressing need, providing portable power while additionally retaining computer settings and program memory.

Not Quite the Standalone Computing Powerhouse

There are 2 major issues with the PC-8401 as a standalone laptop computer. Firstly and most importantly is the lack of physical memory. While the computer has 64k, 32k is devoted to file storage. This is just enough to keep some documents and spreadsheets stored on the device, but severally restricts what ever else you might like to store on the computer.

Secondly, the screen is problematic, it is usable sure, but it isn't great by any stretch of the imagination. The contrast is poor, and compared to the LCD panel clarity of something like the Tandy model 100 it is not up to the task as a main display for extended periods of time.

It's the Peripherals that Make the PC-8401

It  is the bewildering array of peripherals that lift the PC-8401 onto another level. Memory expansion modules, disk drive adapters and CRT monitor modules turn the basic unit into a fully functional C/PM workhorse. Turning the humble PC-8401 into just the kind of computer you'd want if determined to look oh so very serious about your office computing in 1985.



Perhaps the most valuable peripherals are the Disk adapter, CRT/disk adapter and memory expansions unlock the 32k constraints on storage. The base memory can be configured to use the full 64k, with all storage being taken care of by 3.5" DD disks or the memory expansion modules.

OK so Why the Renewed Interest?


Up until now I've not had more than the base unit to play with, and unfortunately even that started to suffer from some LCD problems with the conductive backing peeling of the panel. Luckily, over the past few months I've managed to secure a number of the much vaunted peripherals and a mostly working LCD panel.

So with a (mostly) working LCD panel in place, we can begin exploring the following over the next couple of blog entries:
  • PC-8406A 32k RAM Cartridge
  • PC-8441A CRT/Disk Adapter
  • PC-8431A Micro Floppy Disk Unit

I can confirm that the PC-8441A and PC-8406A are working just fine, however the PC-8431A is yet to be tested as it's a USA version with the wrong power supply for Australia. Not a huge obstacle, although it has delayed testing.

NEC PC-8401 with working PC-8441A CRT/Disk Adapter
In Part 2 we'll begin getting to grips with the expansion units and some of the issues I have with them. This all promises to be quite interesting, hopefully serving to bring this unique CP/M laptop somewhat out of obscurity.

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