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Souped up Compaq Portable 286

R

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Joined
Jun 26, 2019
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31
Location
Portland, OR
Hey guys, I just wanted to show off my tricked out Compaq Portable 286!

So far I've:
- Installed a Compaq EGA card
- Added a 287XL co-processor
- Installed a 16 MHz 80286 CPU (sadly only running at 8 MHz... for now)
- Replaced the green phosphor CRT with a white phosphor tube from a Macintosh Classic
- Converted an 8 bit ISA slot to 16 bit
- Bumped up the RAM to 2176KB, with an XT IDE piggybacked on the AST RAMpage card
- Installed a Sound Blaster AWE64
- And installed internal stereo speakers and an amp
- And finally, added a 16bit 10BASE/T NE2000 ethernet card

I currently have 6 expansion cards in a system with only five slots! Check out some terrible pictures to see how!
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Installing SimCity on Windows 3.1
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Very nice, I like 286s so I like your project. I appreciate the fact that you've taken it a bit farther than swapping average parts by changing the CRT too. It sounds like you have aspirations of changing the oscillator, what chipset does that machine have?
 
You're right, I am looking into putting a faster oscillator on-board, however there are only two oscillators, the 14.318 MHz ISA oscillator and a 48 MHz oscillator near the on-board memory. The speed of the CPU is selected by a key combo, so I'm not certain that I will be able to get the full 16 MHz out of the CPU. There's no chipset on this motherboard, it's more like an XT 286 than an AT or later machine.
 
Awesome mods! I thought I was doing well using a Y power cable and a drive overlay to install a 420md HDD and run DR DOS 7. What else did you have to add to modify the ISA slots?
 
Do you know if the CRT is the same in the original Portable? I wouldn't mind trying out that swap myself. Maybe put the green screen back in the Macintosh!
 
soviet9922 said:
amazing ! do you changed the tube just for the color or it look sharper on the macintosh one ?
Click to expand...

In the original green CRT the sharpness is good, but the phosphor has a very slow fade out; so scrolling games like Commander Keen and games that are white one black like Silpheed, are nearly unplayable. The white CRT makes those games looks great now!
 
RadRacer203 said:
Do you know if the CRT is the same in the original Portable? I wouldn't mind trying out that swap myself. Maybe put the green screen back in the Macintosh!
Click to expand...

Yes, the original Portable, the Portable Plus, and the original Portable 286 all have the same CRT. I want to put my green CRT back in my Macintosh Classic for giggles, but my Classic's logic board is a goner. The battery appears to have defied the laws of physics and completely converted to a tarry acid that ate away 4 of the CPU pins.
 
Moondog said:
Awesome mods! I thought I was doing well using a Y power cable and a drive overlay to install a 420md HDD and run DR DOS 7. What else did you have to add to modify the ISA slots?
Click to expand...

All I had to do for the ISA slot was plop the remaining portion of the 16 bit ISA slot and solder it in. The through holes were already in the board and connected to the bus. ISA is a passive bus, so the only real limit to the number of slots is IRQs.
 
THATS AMAZING The one thing I feel holding portables back is the mono displays. Thats odd they left the last ISA bus at 8bit. Was it to save money. Just seems strange to put in all the traces but leave it blank.
 
When I "rescued" my Portable II from being thrown away, I was also trying to think of deceptive looking gaming PC for taking to lan parties. A Portable clone with modern innards would've been neat. The down side was I had no way to vacuum form or mold large sheets of plastic. The alternative was making plaster molds of the skins, then building a heavy beast out of fiberglass.
 
I'm a great fan of the Compaq Portable machines, especially the Portable II. I was thinking about fitting a faster 286 and swapping the crystal, so I'd be highly interested in your results. I also thought about the feasibility of replacing the 286 with a 386SX - has anybody ever tried that? I imagine it would take a different BIOS to get it to work.

So, please let us know about your progress with the pimped Portable 286 :)
 
diskettenfett said:
I'm a great fan of the Compaq Portable machines, especially the Portable II. I was thinking about fitting a faster 286 and swapping the crystal, so I'd be highly interested in your results. I also thought about the feasibility of replacing the 286 with a 386SX - has anybody ever tried that? I imagine it would take a different BIOS to get it to work.

So, please let us know about your progress with the pimped Portable 286 :)
Click to expand...

386sx requires glue logic and an adapter, upgrades that did this usually did not include a bios update
 
Very nice. I didn't know the Mac and Compaq CRTs were interchangeable.

I also like that trick with the memory card, I've been thinking about doing something similar with my Eagle PC that has only 3 slots (2 used) and needs a memory card with a measly 128k to bring it up to 640k.
 
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