More PX-16 Adventures

Things are progressing quickly with the PX-16.  Having got the main unit working my attention was today turned to the two disk units that came with the Epson.  Designed to hold either one or two FDD’s or an FDD and an HDD the units sit under and clip onto the main machine.  The two units are then connected via a cable at the back.

JVC JD-3824

The first unit I tried seemed dead, no amount of fiddling would coax it into life.  The second unit however powered up first time, although the FDD in it won’t currently read or write to any disks.  The dead unit had a daughter card and from it a cable with a 26 pin connector which I assumed was for the HDD, although I’d not seen that sort of connector before.

Epson Equity

I enquired over at the Vintage Computer Forums as to whether anyone recognised this connector.  Mike S & Chuck G pointed me in the direction of the JVC JD-3824 drive, Chuck remembering it from a Gridlite he used to own.  I did a search for JVC JD-3824 and had a doh! moment when my own blog came up.  This is the drive in my Epson Equity.  I was considering, somewhat reluctantly, taking the Equity apart and trying the HDD in the PX-16.

26 Pin Connector

Then I remembered I had another Equity, seriously beaten up and not working, tucked away somewhere.  I dug it out, took it apart and low and behold there was a JVC JD-3824 drive in it and on the drive that familiar 26 pin connector and cable, I love moments like that!

JVC JD-3824 in the PX-16

I quickly removed the drive, cleaned it up and put it in the PX-16 drive unit into which I’d also installed the daughter card from the dead unit.  I turned it on and… nothing.  Then I noticed a jumper by the mainboard connector to the daughter card.  On checking the unit from which I’d removed the daughter card I realised the jumper was in the alternative position.

PX-16 & Disk Unit

I swapped the jumper, turned the unit on and the HDD whirred into life.  Not only that but it actually booted to the drive’s original installation of MS-DOS.  I was astonished to say the least, it’s noisy and clunky but I love it.

PX-16 Mainboard with ROM Sockets (Right) & Modem (Left)

The PX-16 is highly configurable, in fact it’s so highly configurable that it makes my head hurt.  There’s a bank of DIP switches in the unit to set depending on which configuration you require.  This includes two boot modes, one of which behaves like a regular PC but also denies access to the system’s ROM’s.  I’m still trying to fully understand the other mode.

I’d like to try and get the FDD working next and I want to build an RS232 cable at some point.  The system also came with some additional RAM which I can’t seem to access in the PC boot mode although it’s available in the standard mode so I need to look at that.

Additional RAM

There’s also a Modem in the unit which I’d like to try and I need to do some swapping around to get all the working components into the cleanest cases and secure the various drives properly.

Epson PX-16 Working

Without too much difficulty I’ve managed to get the PX-16 up and running.  The battery won’t currently hold a charge but thankfully the unit can be used with the AC adapter attached.

On first turning the machine on it would simply beep and display some odd glitches on the screen.  After referring to the manual and simply resetting the DIP switches on the unit to correspond with the display that was attached it booted up.

The unit is currently booting from ROM, it can also be set to boot from floppy but I’ve yet to get the disk unit working, there’s also a 26 pin connector in the disk unit which I assume is some sort of proprietary HDD connection.

I’m having a fair amount of difficulty tracking down much information on the PX-16.  From what I can tell it was mainly used in Europe and often by field service engineers.  Its modular design allows you to swap out the keyboard and screen for alternative versions and like the PX-4 it has a removable cartridge on the right of the machine which can house various peripherals.

Epson PX-16 Throws A Googly

It’s looking as though this Retrochallenge is going to end up considerably less focused than the last.  Not helped by a late start due to a family holiday I’ve now been thrown a googly by the arrival of a new machine.

For some time I’ve lusted after an Epson PX-16 and with one recently listed on Ebay it was an opportunity not to be missed.  Listed as non-working but including some additional bits such as a spare screen and disk unit I felt confident I’d be able to resurrect it so I put in a bid.  Somewhat amusingly for me, not so much the seller I got it for 99 pence.

It’s in good condition cosmetically and I’ve put it on charge hopeful that I’ll be able to get it working tomorrow.  Information on the PX-16 is pretty scarce, as usual for old Epson stuff the best resource is Fred Kraan’s excellent site.


I shall try and find out some more information and take some better pictures in due course.  For now I know this machine runs MS-DOS 3.2 from ROM and has an 8088 compatible V20 processor.  In the picture above the PX-16 is sitting on top of the optional disk unit which can house two floppy drives or a floppy drive and hard disk.