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Compaq Portable 286: repairs, testing, and other items

R

retro-pc_user

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Oct 13, 2017
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Location
SE Michigan, USA
I got a Compaq Portable 286 from eBay and arrived in 1 piece (thanks to the seller for packing it like a tank) and it had 1 issue that needed to get addressed: power cycling due to a sticking MFM Miniscribe 20MB HDD.

I disconnected the power from the drive, the data cables, and removed the controller card before powering it back on.

After that, it sprang to life and prompted for the user programs diskette to adjust the settings. After inserting the diskette, I typed in the usual DIR command to find the program to open the settings and when I pressed enter, nothing happened.

I cracked open the keyboard and found out the enter key's foam and foil pad was completely done for (fell apart). Fortunately, the rest of the keys are fine and working and after I replaced the foam and foil pad and repaired the enter key (plastic snaps broke off), the key works and I was able to continue.

I got my sound card, XT-CF + 64MB CF card, and moved the floppy controller so I can use the HDD indicator light from where the MFM drive was at installed and the card that I had installed wasn't booting to DOS. I installed the other CF card from my XT variant and it booted up.

Gotta fix the non-functional 64MB CF card (reports missing operating system) and replace the battery since it's so low the clock isn't right after powering the system off and on.

My future plan is to install an EGA + VGA card in place of the Compaq VDU card or an EGA card since some games like EGA or better (mainly The Curse of Rabenstein).

It has 640KB RAM, either a 1.2MB or 360KB FDD, 8MHz 286 CPU, tape drive, CGA, floppy/serial/parallel card (standard), and the keyboard is a Key Tronic (similar to the IBM Model F AT).

Also needs a lot of TLC, but as long as it boots up, I'm good to go.
 
Upgraded the floppy drive to a dual 1.44MB and 1.2MB drive and the tape drive was taken out for the Mitsumi CRMC-LU005S after I trimmed the tray on the drive itself.

I still have the floppy drive and the tape drive. However, the EGA cards I attempted to use aren't working (ATi EGA Wonder and Genoa 4880) with the correct parameters set using GSETUP and the battery is one of those camera style Lithium that has 1.45-1.5V left, which is okay, but without the battery, the RTC and CMOS settings will be erased or the RTC isn't 100% functional if the battery level is below a certain point.

My next quest is to find a Compaq EGA card so I can have EGA graphics on an internal monitor.
 
If you have an ATI EGA wonder you should be able to drive the internal display with an appropriate adapter.


page 21 (22 of pdf file.)

Threads detailing how to build the adapter:



You’ll have to build the adapter yourself as it’s not available anymore and to do this you’ll need a small breadboard, some jumper wires, 3 diodes, and a AD8055 op amp IC.
 
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