Technology and retro computer blog

Compaq Portable II Restoration

I recently acquired a Compaq Portable II.  It was great to get hold of this machine because I have the Compaq Portable I and III, so this completed the set.  This machine was somewhat of a basket case, the video board was defective and was preventing it from starting.  Initially on power up there was a beep and a red flashing light on the front.  The seller was good enough to diagnose this before I bought the machine and supplied a replacement IBM EGA (IBM 6278173XM), board to get the machine running.  The EGA board allows the machine to start up but it doesn't have the connector to drive the internal CRT, so you have to use an external monitor.  The 360k 5.25” floppy drive in the machine worked but the door was very sticky and wouldn’t open or eject disks properly, but luckily it read disks fine.

IBM 6278173XM EGA board

Another problem was that the hard drive only worked once the machine warmed up.  This is a classic case of "sticktion" where the head is stuck from being inactive for many years.  The hard drive is the original 20mb MFM drive (type 2).  It has the MFM to IDE converter board attached to the bottom, so it's a great piece to have, but considering the reliability issues the plan was to replace it with a later model IDE drive or CF IDE adapter.  At least when the machine was booting from the hard drive it was evident that everything was working.

The defective GA2 video board

Onto disassembling the machine to get to the drives and boards.  I found a copy of the Compaq Portable II service manual online which had directions on how to disassemble the machine.  Disassembly of this machine is quite different to the Compaq Portable I, I had to refer to the manual to work it out.

Compaq Portable II - Maintenance and Service Guide.pdf

One of the first tasks was to remove the floppy drive and service the eject mechanism.  I used some lithium grease on the hinges and on the head mechanism.  The heads also got a clean with a cotton bud.  This got the eject mechanism working smoothly.

In order to test the internal CRT the video board from my Compaq Portable I was installed.  The connector for the internal CRT is the same on both machines.  Connecting the internal CRT cable required some re-routing through the case, as the connector is at the other end of the board.  Once connected the internal CRT worked fine.  The picture geometry and brightness were all really good.  The video board from the Compaq Portable I works in this machine but it’s considerably taller and protrudes out of top so you can’t get the case back on.  So it’s only a temporary fix.

Now that the internal CRT had tested successfully it motivated me to get a replacement video board.  A search on U.S Ebay found several Compaq Portable video boards for sale, but they were rather expensive considering I have to pay international postage and exchange rates.  I found a listing for a later model video board (Assy no. 000525) for a reasonable price so I bought it.  This video board is listed in the Compaq Portable II technical manual as an option so it’s an appropriate replacement.

Having sorted out the video issue for now my focus shifted to replacing the hard drive.  I have several newer IDE drives but they’re all fairly large by the standard of the Compaq Portable II.  The smallest I have is 40gig.  The Compaq Portable II setup disk only caters for a selection of specific drives and none are anywhere near that capacity.  I’ve read that these larger drives can be used with the assistance of a BIOS overlay which is specific to the drive’s brand.  I instead decided to try using a compact flash IDE adapter that I have.  Trying several hard drive types using the Compaq Setup utility, I eventually succeeded with the 20mb type 2 hard drive option.  The CF card in use was 1gig, so it wasn’t a very good  use of its capacity.  I have a couple of smaller CF cards that are closer in capacity to those in the setup utility, so I’ll try to get one of those working later, but at least for now the 1gig card works.

With the convenience of having the CF hard drive working I was able to easily copy some applications over to the Compaq Portable II.  I loaded up several games and installed Windows 3.  I also plugged in a serial mouse to use with Windows, everything worked fine.

The machine has several extra boards installed, an Analogue Devices CT-180 which is an analogue to digital controller board.  It also has an SMC network card.

SMC network card
Analogue Devices CT-180

Update: I've now managed to get a 160mb CF card working as a type 25, 134.5mb hard drive.  So only around 25mb of this  card is lost.  After using the DISKINIT utility on the Compaq setup disk I could see this CF card as the C: drive, but I couldn't boot from it.  On restart with boot floppy removed, the system would just stop booting with a blinking cursor in the top left of the screen.  I fixed this by running the following command:


This fixes the master boot record of the disk (CF card).  Once that was done the machine now boots from this CF card fine.

Compaq Portable II post 2:

New video card and sound card for Compaq Portable II

Dungeon Hacks: How NetHack, Angband, and Other Roguelikes Changed the Course of Video Games

Dungeon Hacks, David L. Craddock

I was contacted recently by David L. Craddock who requested the use of a screen shot of Rogue that I have in my early Macintosh disk archive.  The screenshot was for use in his then upcoming book Dungeon Hacks.  He offered a pre-release copy of the book for review which I was happy to accept.  The book covers the development of the RPG game genre of Roguelikes, named after Rogue the game that started the genre.

I really enjoyed reading this book.  It's extremely well researched and written and has a great deal of interest in it, not only for people into this genre of RPG gaming but for anyone interested in computer and software history.  For example, early pioneers of Rogue were directly in contact with people like Dennis Ritchie who was instrumental in the development of Unix and C. 

I was never one who got into Rogue or any of the directly related RPG games on the Unix platform, but I did relate to many of the games and people mentioned in the book.  For example, there’s a section in the book on Sword of Fargoal on the VIC20.  My first computer was a Commodore VIC20 and one of my all-time favorites on that computer was Sword of Fargoal.  I recall at the time I had to borrow $90 from family members to buy the game and the 16k memory expansion cartridge required to run it on the VIC20.  This was a lot of money at the time.  I recall the great excitement of playing that game and finally finishing it.

I highly recommend Dungeon Hacks for anyone interested in RPG's and the history of game development.  Many of you I'm sure will relate to at least some of the games and platforms they ran on.


Dungeon Hacks is now available for purchase on Amazon here:


Also here:

David L. Craddock, the author of Dungeon Hacks


Epson HX-20 Revival

I recently saw an Epson HX-20 for sale on a local trading site, what initially caught my attention was that it had an integrated printer and micro tape drive.  Very cool!  Not knowing much about these machines I did a bit of research on it and was impressed to hear it's considered the first laptop.  I generally like to collect machines that have some historical significance, and limit my main collection to stuff from the late 70's and early 80's.  It fit the bill nicely, so I snapped it up.

Epson HX-20
Epson HX-20 with case
Epson HX-20 lcdscreen


  Epson HX20 specifications
  Manufacturer      Epson
  Release date   November 1981
  CPU   Two Hitachi 6301
  Speed   614 kHz
  Ram   16k to 32k
  Rom   24k (3 x 2764, 8k eproms)
  Storage   Cassette internal 
  Expansion   1 optional 8k 2764 eprom slot 



  Rom basic


 120x32 pixel LCD display



SkiWriter rom   SkiWriter rom


As is quite common with these old machines it was untested and had no adapter, but it's condition was great and it came with the hard case and an extra eprom.  I was hoping that getting it running would be as simple as finding a suitable adapter, I have an adjustable multi-fit adapter which did fit but on initial tests it wouldn't power on.

From reading posts on various sites, I found that these machines require a functional internal battery to operate even with the adapter plugged in.  So I proceeded to take it apart and found not surprisingly that the internal NiCd battery had perished (see pic above).  Luckily the leakage of the batteries was contained within the plastic wrapping of the battery pack.  The corrosion had also made it's way up the battery leads and started to lightly corrode the connector on the motherboard, but the board connector was easily cleaned. 

I removed the battery and cut off the battery leads, they were totally corroded and could not be saved.  I tried removing the battery leads from the connector on the lead side, but they were stuck with corrosion.  So I soaked the connector in white vinegar for a couple of hours and was able to remove the corroded leads.  I made up new leads using the wires from a pc 3.5" floppy connector.  The floppy connector pins fit perfectly into the HX-20's battery lead connector. 

Prior to making up new batteries, I was eager to test whether the machine worked, so I connected my adapter directly to the battery leads and plugged it into the mother board. I set the adapter to 4.5v and the machine came to life!  The adapter I have is voltage switchable but is only 300ma.  There wasn't enough power to run the tape drive or the printer but I could run Basic and enter in a simple Basic program.  Three items were displayed on the lcd: 1 Monitor; 2 Basic and 3, there was an optional rom installed called Entecard.

I found the posts below which discuss making a new battery pack for the HX-20:

I managed to find the exact same batteries at my local parts store, so I made up a new battery pack and attached the new leads.  I partly re-assembled the machine with the new battery and plugged in the  adapter and was able to monitor the battery voltage.  I saw the voltage on the battery going up as the adapter was powered, so this was a good sign that the batteries were charging. 

I fully re-assembled everything and after a few hours of charging I was able to get both the printer and the micro-tape drive working!  The printer ribbons that came with the machine were long dead but replacements are still widely available.  The printer paper is also readily available as it just uses 2.25" cash register paper.  There was also an original Epson micro-cassette that came with the machine which still reads and writes ok.

Now that I had a fully functional machine I started looking for software that would run on it.  There's plenty of Basic programs available on various sites, but the main one I wanted was Skiwriter.  It then occurred to me to check the extra rom that was supplied with the machine, and it was an original Epson Skiwriter rom.  It was in a sealed plastic bag so it may have never been used.  I removed the rear plastic cover replacing the installed Entecard rom with the Skywriter rom. On power-up I was greeted with the Skiwriter option on the menu.

Skiwriter ROM

Skiwriter is a word processor application for the HX20.  The zip file below contains an image of the Skiwriter eprom in both .bin and .hex versions.  To use Skiwriter on your own HX20, create a 2764 8k eprom using either the .bin or .hex image file. (14.06 kb)

Skiwriter Manual

This is the only electronic copy of the Skiwriter manual known to exist.