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What did I find?

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fred3rd

Experienced Member
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Apr 29, 2006
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Central Pennsylvania U.S.A.
What did I find? It's definitely a Compaq portable, but which one. I think an origional portable from 1983. The fcc id # is cnt 75mcompaq and the model is COMPAQ, according to the data plate on it. The only badge on the unit is COMPAQ. It has the drive bays going top to bottom (vertical) as apposed to the Portable II I had with the drive bays running left to right (horizontal). The real puzzler is the fact that it has 1) full height 5 1/4 floppy drive, 1) half height 3 1/2 floppy drive, and 1) 1/2 height HDD. All information I've found on the original Portable only specs it with 2) 5 1/4 floppy drives.
Also what OS is it capable of, basic, dos 1.0 ?
I've attached a photo to help in identifying this gem.
 

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Looks like an original Compaq Portable (some refer to it as the Compaq Portable I) from 1982. Should be an 8088 CPU at 4.77 MHz with 360K floppys. Nice find.
 
fred3rd said:
The real puzzler is the fact that it has 1) full height 5 1/4 floppy drive, 1) half height 3 1/2 floppy drive, and 1) 1/2 height HDD. All information I've found on the original Portable only specs it with 2) 5 1/4 floppy drives.
Click to expand...

The 5.25" drive is original, the 3.5" drive and hard disk are not.

fred3rd said:
Also what OS is it capable of, basic, dos 1.0 ?
I've attached a photo to help in identifying this gem.
Click to expand...

Any version of DOS could be used. The very first Portables used Compaq DOS 1.12 (equivalent to PC-DOS 1.10 except for the RAM-resident BASIC), but the great majority used DOS 2.0 or later.
 
Yup, that's the original portable. It's been upgraded though. It shipped with two floppy drives, but it's pretty common to find one where someone has replaced one of the floppy drives with a half height hard drive and a half height floppy. Inside, it's very much like any other PC clone, with ISA slots and stuff, so it was easy to upgrade. It's also pretty common to find HardCards in these things.

It'll run any software that the PC or XT will run, it's the first 100% [1] compatible clone. So, you're free to run whatever version of DOS you want.

-Ian

[1] At least, it's compatible enough - to the point where I am not aware of any piece of software that won't run on it. It's not a direct copy of the IBM ROM though, it was developed by reverse engineering.
 
Gentleman thank you for the information. You've confirmed what I suspected. Now the issue is the kb is unresponsive. When it asked for the current date the only key that worked was the "k". Now that's dead also.
 
fred3rd said:
Gentleman thank you for the information. You've confirmed what I suspected. Now the issue is the kb is unresponsive. When it asked for the current date the only key that worked was the "k". Now that's dead also.
Click to expand...

Common problem on those. The keyboard is the same style as the infamous Sol-20 keyboard, or the TRS-80 Model II keyboard, or the Sun4 keyboard. If the foam discs have not deteriorated it's an easy fix, here's what to do:

Flip the keyboard over and take out the screws. Flip it right side up and remove the top cover. Remove the screws holding the keyboard mechanism to the back cover, flip it over and remove the back cover. Disconnect the cable, remembering the orientation. Remove the screws holding the circuit board to the keyboard mechanism, and carefully remove the board. The board is covered with silver colored pads - these are the key contacts. You'll note how the foam discs on the bottom of the keys have little silver discs on them. A common problem is oxidation and crud buildup on the circuit board pads. Using a paper towel and 91% Isopropyl alcohol, clean the circuit board contacts the best you can. Inspect the foam discs - if the foam hasn't deteriorated, then you should be good, most of the time cleaning the board is good enough. Reassemble with just enough screws to hold the board on, and test it.

If you have damaged foam pads, you'll have to fabricate or find replacements...

-Ian
 
RetroHacker_ said:
Yup, that's the original portable. It's been upgraded though. It shipped with two floppy drives, but it's pretty common to find one where someone has replaced one of the floppy drives with a half height hard drive and a half height floppy. Inside, it's very much like any other PC clone, with ISA slots and stuff, so it was easy to upgrade. It's also pretty common to find HardCards in these things.
Click to expand...

He's lucky that this one has a 3.5" drive in it, as that gives twice the storage capacity of 5.25" disks. The only catch is that he'll need to get ahold of DD 3.5" disks (regardless of what others say, I do not trust covering the hole on HD disks).

RetroHacker_ said:
It'll run any software that the PC or XT will run, it's the first 100% [1] compatible clone. So, you're free to run whatever version of DOS you want.
Click to expand...

Yep, almost any software made through 1990 will work. The video card (this is important to remember) is the original Compaq VDU, which is basically CGA, except that it outputs an 18 Khz (ie. MDA) frequency for the internal display (the external outputs use the normal CGA 15 Khz).
 
RetroHacker_ said:
Common problem on those. The keyboard is the same style as the infamous Sol-20 keyboard, or the TRS-80 Model II keyboard, or the Sun4 keyboard. If the foam discs have not deteriorated it's an easy fix, here's what to do:

Flip the keyboard over and take out the screws. Flip it right side up and remove the top cover. Remove the screws holding the keyboard mechanism to the back cover, flip it over and remove the back cover. Disconnect the cable, remembering the orientation. Remove the screws holding the circuit board to the keyboard mechanism, and carefully remove the board. The board is covered with silver colored pads - these are the key contacts. You'll note how the foam discs on the bottom of the keys have little silver discs on them. A common problem is oxidation and crud buildup on the circuit board pads. Using a paper towel and 91% Isopropyl alcohol, clean the circuit board contacts the best you can. Inspect the foam discs - if the foam hasn't deteriorated, then you should be good, most of the time cleaning the board is good enough. Reassemble with just enough screws to hold the board on, and test it.

If you have damaged foam pads, you'll have to fabricate or find replacements...

-Ian
Click to expand...

The foam pads are shot, most of the conductive surfaces are shot as well. The circuit board is flawless. Any ideas where to get replacements or am I on a fabrication mission? I'm thinking 1/8 inch thick foam if I can find some and household aluminum foil. Any suggestions?
 
http://www.sol20.org/keyboard.html

Read that over first. Erik found some old Sun keyboards and took them apart to grab the foam pads. When I was blowing thru some money I had, I purchased mine on ebay for $60 for a set. Appears price has gone up since then. I don't recall the exact model for the Sun keyboards, type 4 or something. Maybe the above URL mentions them somewhere. Could ask Erik where he found the Sun keyboards at. I never could find any on ebay when I went looking, altho I didn't look for all that long.
 
Sun type 4. I've had a horrible time finding any 'round these parts.

There are others that used the same technology (probably any late 1980s, early 1990s Keytronics keyboard) but I haven't found a reliable way of identifying the types without snapping them in half. . . :p
 
Mine appeared to have a plastic disk coated with a conductive material, which is now almost completely gone. I suppose a tin foil substitute is out of the question.
 
fred3rd said:
Mine appeared to have a plastic disk coated with a conductive material, which is now almost completely gone. I suppose a tin foil substitute is out of the question.
Click to expand...
Not at all! Get some double-sided foam tape and aluminum foil and make a few to try out; nothing to lose except a little time. Good luck!
 
fred3rd said:
Mine appeared to have a plastic disk coated with a conductive material, which is now almost completely gone. I suppose a tin foil substitute is out of the question.
Click to expand...

Rather than tinfoil I'd suggest a mylar anti-static bag (the kind they ship boards in) as it's closer to the composition of the original disk.

I don't remember where, but someone had a tutorial on how to make these using common foam, plastic film transparencies and mylar bags.
 
I used double sided foam tape and foil on the return key. I figured this would be a good test if I could blow by "enter new date" ect. instead it gave me a string of about 8 characters. I then removed the board and used my fingers to close the contacts. This was very cumbersome,(counting contacts to locate desired letters), but it worked. ver rendered dos 3.3, cool. So I'm back to the drawing board to resolve the original problem, the wafers in the kb.
 
fred3rd said:
I used double sided foam tape and foil on the return key. I figured this would be a good test if I could blow by "enter new date" ect. instead it gave me a string of about 8 characters. I then removed the board and used my fingers to close the contacts. This was very cumbersome,(counting contacts to locate desired letters), but it worked. ver rendered dos 3.3, cool. So I'm back to the drawing board to resolve the original problem, the wafers in the kb.
Click to expand...
---
8 *characters*? I could see key bounce, i.e. multiple returns, but characters? Are you sure you didn't accidentally connect to another adjacent pad/trace with the foil?

There are kits out there for ~12.00 or so to restore the conductive material on the bottom of the more usual rubber key plungers, but that wouldn't solve your problem with the deteriorating foam. Keep experimenting, and share your ultimate success with us!
 
MikeS said:
Foil has worked for me, but I suppose anything reasonably conductive would do. What's the transparency film for?
Click to expand...

The pads for these old Keytronics 'boards have three layers: on top (closest the key) is a plastic disk that is designed to catch clips on the key to keep the assembly in place. Next is a compressable foam layer and finally there is the contact. As you said, foil will probably work, but I'd worry about durability versus the mylar.

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