Technology and retro computer blog

Compaq Portable II new video and sound card

I recently received the replacement video board for my Compaq Portable II and I'm glad to say it worked perfectly.  See my previous post about the CPII here.  The board is Assy. No. 000525 which is a later board than what was in the machine, but it's an appropriate board for the Portable II.  There's much fewer components on this board and many of the components are surface mounted. It's great to have the internal CRT working again.

Working internal CRT
Working internal CRT
VDU Assy no 000525
VDU Assy no 000525

The Compaq Portable II is great for running CGA games, so I decided to get a sound card for it.  I managed to get hold of a Sound Blaster Vibra 16 CT4180.   This is the cheaper plug and play version of the Sound Blaster range, but it worked out well.  These cards also have a game port connector for connecting a 15 pin joystick, so needless to say I've got one of those coming as well.

I purchased the Vibra 16 not really knowing whether it would work on a 286 machine.  It’s a 16 bit board and I’ve got a spare 16 bit slot in the CPII, so I figured I'd work it out once it arrived.  Getting the sound card working in DOS took a bit of effort but I got it working.  The Vibra 16 is a PNP card designed for later machines than a 286.  So at first when I tried to install the drivers the card wasn't detected and running the Sound Blaster configuration manager would lock up the machine.

creative vibra 16 ct4180
SB Vibra 16 CT4180
creative vibra 16 ct4180 connectors
Vibra 16 ports
Compaq Portable II cards
Video & sound cards installed

In doing some research on the web I discovered a utility called EMU386 which is a driver that will emulate 386 opcodes on a 286.  The Vibra 16 software must use some 386 opcodes and therefore requires EMU386 to install properly. Once Emu386 was installed, I then installed the Sound Blaster basic drivers and the Sound Blaster Configuration Manager.  These two installs made all the necessary changes to the autoexec.bat and config.sys files and once I restarted the sound card worked.

Vibra16 sound card detected
Sound card detected
Compq Portable II ports
CPII card ports

While I was at it, I also installed MSDOS 6.22.  This took a bit of effort because I don’t have a 1.44 floppy connected to the machine, it only has the 360k floppy drive.  I didn’t like the prospect of creating 360k install disks for DOS 6.22, so I looked for another solution.  I’ve got a DOS 6.22 360k boot disk, so I used that to format the hard drive with the system files:

A:>format /s/q

This does a quick format of the hard drive and installs the system files required for a hard drive boot. Once that was done I simply removed the CF hard drive and connected it to my Windows pc.  I then manually created the DOS folder and copied the DOS files from my PC.

Here’s a video of the Compaq Portable II with Sound Blaster Vibra 16 running Prince of Persia, the sound is really impressive.


See below for EMU386, Sound Bster Vibra 16 DOS drivers and the DOS 6.22 CD image. (1.79 mb) (18.15 kb) (1.15 mb) (671.25 kb)

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

Compaq Portable

I saw this Compaq portable advertised in my local area, not knowing much about these machines I did a bit of research on it. I discovered that it was not only the first IBM pc clone but also Compaq's first product from the early 80's. I really like these old "portables" with built in CRT's so I snapped it up. The price was fairly cheap, so I bought it without doing much testing. The seller didn't have any working boot disks, so I just tested that it powered up and displayed a missing boot disk prompt on the screen, that was good enough for what I paid.


Compaq Portable Compaq Portable Inside Compaq Portable Inside


Compaq Portable specifications
Manufacturer Compaq
Release date January 1983
CPU Intel 8088
Speed 4.77MHz
Ram 128k to 640k
Storage internal 5.25" 360k floppy x 2
Expansion 3 slots
Ports Serial, parallel, composite video out
OS Compaq/MS DOS


Compaq Dos (177.65 kb) (1.05 mb)


On getting it home and doing some initial testing, I was happy to get it to boot from the A drive with a DOS 3.3 boot disk, but on the down side, I couldn't get any of the keys on the keyboard to respond. No really being able to do much more at that stage I pulled it apart and and gave it a full clean out. On pulling apart the keyboard I discovered that is uses sponge foam as a spring inside the keys.  I've never seen these before, but in doing a bit of reading I found out they are used on several other models like the Sol20 and Apple Lisa.  It was pretty clear to see why none of the keys were working as both the sponge material and the Mylar on the key pads had totally perished (see photo below).


I read a great guide on the Solviant website about replacing keys on the Sol 20.  The guide suggested making your own pads using sponge discs topped with aluminum foil and clear plastic tape. I didn't have any sponge material on hand so I just used some padded double sided tape instead. I create a test key and tested it on the keyboard pcb and all keys worked. I then proceeded to make similar pads for all keys on the keyboard. This took a couple of hours but once re-assembled, I had a fully working keyboard. The keyboard fix was good as I can now use the machine, but I'm not happy with the feel of the keys. The double sided tape that I used does have some spring to it, but it's way too hard compared to the sponge material. So at some stage I'll redo the pads using a more appropriate material.

With a working keyboard I did some further testing on the machine and found that the B drive didn't read any disks. I pulled it out and cleaned it internally and also did a thorough head clean, on re-installing the B drive it now reads some disks, but it's not perfect. I've noticed it gets to a certain track on the disk and then comes up with read errors. I'll need to extract that drive again and check the rails for debris. I can launch some programs from that drive now so it's better than before. Everything else on the machine seems to work well, the display is good, there's some geometry issues, but the green screen display is very sharp and there's no sign of any burn in. The machine has the floppy controller/printer card, an AST SixPakPlus clock/memory/serial upgrade card installed.  Memory reports at 640k, I also replaced the 3v battery on the AST card and I found the AST clock utilities on web, the clock now saves the date and time.

IBM 5150 PC

This is my IBM 5150 PC.  The 5150 was the first model of IBM pc, first released in 1981.  This one is dated 1983 and has the dual 360k 5.25" floppy drives.  The first model 5150 had 160k 5.25" floppy drives.  I bought the computer untested, I gave it a good clean and fired it up, everything worked.  I've installed an XT IDE compact flash hard disk card in the machine.  The CF card I've used is 32 meg which is plenty for a machine this age.  The power supply in the 5150 is not powerful enough to power a typical hard disk from this era.  The first hard disk model IBM PC was the XT which had a bigger power supply.


1983 IBM 5150 with PS2 vga monitor and Microsoft Green Eye mouse Microsoft Green Eye mouse dated 1985


  IBM 5150 PC specifications

Manufacturer    IBM
Release date 12th August 1981
CPU Intel 8088, 16 bit
Speed 4.77MHz
Ram 16k to 256k
Rom 40k
Storage two 5.25" 160k internal floppy disks  
Expansion 4 expansion slots
Ports Cassette, optional serial, parallel
OS IBM Rom Basic, PCDos 1.0



The mouse attached to the 5150 is the original Microsoft "Green Eye" mouse.  It was introduced with the first version of Windows in 1985.  This particular one has a DB25 connector and works with the generic CuteMouse serial mouse driver.


I've installed MS DOS 6.22 as the base operating system and I've also installed Windows 2.0.  I've also got some DOS games installed like Galaxian and Pacman.  The software gives you a good idea of what this pc was capable. of.


This machine has a Video 7 VEGA graphics card installed which has both 15 pin VGA and 9 pin CGA/EGA outputs.  The card can be jumpered from the rear of the machine to switch between the two outputs.


Microsoft Green Eye mouse top


XTIDE card and compact flash hard drive

In the last two slots seen above is a compact flash IDE card (left), attached to the the XTIDE card (right).  This allows the IBM5150 to use more modern IDE hard drives.  As my machine has the original 60 watt power supply I believe it wouldn't be enough to run an original IBM hard drive.  This is a good solution as the comact flash card is very low power and it can be removed and connected to a modern pc for copying software over to the 5150.  It also allows the 5150 to return to it's original dual floppy and no hard drive configuration simply by removing these two cards.