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Looking for very special portable pc with color monitor

jscipione

jscipione

Experienced Member
Joined
Feb 8, 2021
Messages
62
Location
Rochester, NY
Dear VCF,

I am looking for a very special kind of portable computer aka luggable that almost doesn’t exist. I am trying to find a portable pc like the IBM 5155 or Compaq portable but with a built in color CRT monitor and a 386 CPU. I’ve found a couple examples of this kind of computer online but none for sale.

Examples:
https://www.computerhistory.org/collections/catalog/102716058
https://retrocomputing.stackexchange.com/questions/8439/can-anyone-help-me-identify-this-computer

Apparently these were made by various manufacturers in the early 1990’s and tend to be unbranded or have a generic brand on them. It seems like they tend come with a 386 era CPU like a 386sx-16.

Here’s one I found on eBay that is really close to what I’m looking for but it unfortunately has a monochrome screen, not color:
https://www.ebay.com/itm/Vintage-Portable-PC-Computer-w-Carrying-Case/233878656133

I figure that if anyone knows where to find one of these it would be here. So does anybody know where to find one of these unicorns? The one on eBay I linked to above appears to have a rare ATI EGA Wonder video card in it which makes it a tempting computer. If the monitor was color it would be a no brainer. Unfortunately it doesn’t seem to work, the screen is shown as amber, and the dip switches on the back are set to TTL monochrome mode so I’m almost sure that it’s not color.

If this request is asking too much I apologize but I would like to get my hands on one of these. I’ll keep looking on eBay to see if one shows up. Cheers!
 
That is a very good question. I have only seen a couple of machines like that come up on eBay over the years. By the time of the 386, most portable machines were using early LCD or Plasma screens.

Keep in mind that anything with color still might not be VGA compatible, if that is what you are looking for. An internal color CRT could be CGA RGB/Composite, EGA, or something proprietary.

Early color CRTs were very hard to read, so most business oriented machines had monochrome.
 
SomeGuy said:
Early color CRTs were very hard to read, so most business oriented machines had monochrome.
Click to expand...

The CRT isn't the problem, the video standard used to get color on the CRT was the problem. Early home computers that were color capable usually used composite video and NTSC in countries that used it. NTSC is a horribly lossy video standard that suffers from a range of visual artifacts due to the way the chroma and luma information are muxed together. Some home computers were worse than others, the Apple II for example since it didn't really conform to NTSC and was more a loose approximation of it.

When digital RGB became a thing, the issue of color garbling text vanished, it was just a lot more expensive. Digital RGB has existed since at least the CGA color standard.

jscipione said:
I figure that if anyone knows where to find one of these it would be here. So does anybody know where to find one of these unicorns? The one on eBay I linked to above appears to have a rare ATI EGA Wonder video card in it which makes it a tempting computer. If the monitor was color it would be a no brainer. Unfortunately it doesn’t seem to work, the screen is shown as amber, and the dip switches on the back are set to TTL monochrome mode so I’m almost sure that it’s not color.

If this request is asking too much I apologize but I would like to get my hands on one of these. I’ll keep looking on eBay to see if one shows up. Cheers!
Click to expand...

A potential idea would be to buy the machine and gut the monochrome CRT and associated circuitry out of it, and transplant a color CRT in. Maybe a small PVM, you'd just have to figure a way to mount the new internals in.
 
GiGaBiTe said:
The CRT isn't the problem, the video standard used to get color on the CRT was the problem.
Click to expand...

Shadow mask pitch is also a significant factor when you get down to sub-13" color CRTs. Most tubes that small just can't physically quite do 640 vertical lines with complete clarity. If the monitor's well tuned otherwise it'll probably look "fine", but strictly speaking monochrome tubes don't have this problem.

That said, the real reason the color tubes were rare probably has more to do with:

A: They were *significantly* more expensive and a portable computer like that is already a really expensive and fragile thing you're committing to lug around.
B: They're heavier. (Color tubes come in slightly different sizes than monochrome tubes and typically the color variant in a given "slot" is slightly larger; for instance, if you're an old **rt you'll remember how small B&W TVs were usually sold as "9 and 12 inch" while color TVs were "10 and 13 inch". And it's also more complicated inside.)
C: They're slightly more fragile. The presence of the shadow mask and convergence issues means a good smack or drop is more likely to hurt a color TV.

This is why this market niche was mostly left to the offbrand cloners; I suspect most "big names" didn't want to put their name on something that might end up being a reputational black eye.
 
The IBM 5155 and Compaq Portable I and II seem to use an internal composite video out header on the CGA card to output video to the internal monochrome monitor while retaining the digital out and composite out on the back of the card for use with an external monitor. The later clone versions with a 386 get around not having this internal composite header by snaking the monitor cable from inside the case to the digital RGB connector on back of the video card with no allowance for an external monitor. So in theory this should be able to work with a color tube. I’m aware that this probably means CGA or EGA color, not VGA as SomeGuy noted and I’m ok with that.

If a color monitor version of this kind of computer didn’t exist at all then I’d resign myself to monochrome, but knowing that it does exist even if rare means that I don’t want to settle for monochrome. The Haco model shown in the Computer History Museum link appears to be color at least as there is a telling red, blue, and green stripe underneath the tube. The computer picture on the retrocomputing stack exchange link also appears to be color from the white phosphor of the screen, although I suppose that it could be a white monochrome screen instead.

GiGaByTe’s idea to try and retrofit a color CRT into a monochrome case is going to be quite difficult as it’s almost impossible to find a color CRT that will fit and will be able to hookup to the power supply. It would be quite expensive to do this too. I was thinking the same idea and was looking at small color monitors/TVs like the Sony one’s to see if I could do a tube transplant but there doesn’t seem to be any assurance that the tube would fit or would be able to hook into the power supply that the case comes with. Maybe if I knew of a tube that would be able to fit and hookup this idea would be viable.

edimophorodon’s explanation for why these cases typically don’t include a color monitor is probably the reason I’ve yet to find one of these with a color monitor that actually works. This will be a tough find indeed. I’m just going to have to keep looking. Thanks for your helpful explanation.
 
I remember seeing those Compaq-clone luggable cases advertised in Computer Shopper magazine, either as empty cases you could put your own components into, or as complete white-box PCs. They were advertised as having a 9-inch Sony Trinitron color CRT.
 
vwestlife said:
I remember seeing those Compaq-clone luggable cases advertised in Computer Shopper magazine, either as empty cases you could put your own components into, or as complete white-box PCs. They were advertised as having a 9-inch Sony Trinitron color CRT.
Click to expand...

Me as well, I think it was my 1993 computer shopper. Which I may still have but couldnt say where. It featured a couple generic AT luggable cases with a built in color CRT with 640 x 480 resolution (no higher) and a 486 SX I think.
 
Yeah that looks similar to what I remember the ad looking like. I somewhat remember a Parrot in the photo not a tiger though. I know I wanted one so badly for a portable desktop. I owned my first Compaq portable 1 then (Im talking early 1990's) but I didn't know a fraction of what I know now and broke it and threw it out. But yeah, where did these cases go? Do they take any AT motherboard? You could do alot with VGA resolutions, I have a 640 X 480 projector in my bedroom against an automatic 120" projection screen for streaming. Its like having your own theater and I dont care about it only being VGA, from the other side of the room it appears fine.

I would but a 233MMX Pentium one in that case if I ever found one.. Or an AMD K6-2
 
1990 not 1991...

I’m guessing that you could replace the motherboard with another one that would fit but the trick is to find one of these with a color screen. I got the eBay seller excited by viewing the one he’s got a bunch of times but it’s got a monochrome monitor and I want color! I’m guessing that a lot of these cases got put in landfills like your Compaq Portable did and so they are exceedingly hard to find now.

I searched for Modgraph GX-2386 and there are no results on Google or eBay, not even long gone ones from the past. There probably weren’t too many of these sold to begin with and the company is now long since defunct.

I found a higher resolution version of the ad in the July 1990 issue of Byte magazine so that dates the product pretty well to 1990. https://vintageapple.org/byte/pdf/199007_Byte_Magazine_Vol_15-07_Low-Cost_Laser_Printers.pdf
 
I’m almost 100% positive the COMPAQ Portable’s internal CRT is NOT composite, considering it’s dual-mode and how good the color shading is. Also, the internal connector uses like 5 or 6 pins instead of two like the 5155. The 5155’s composite CRT has problems with certain colors causing text to be illegible. The COMPAQ doesn’t have this issue.

vwestlife, I knew that looked like a Trinitron in one of the units pictured above!
 
The color ones probably use the CRT out of a 9-inch Sony PVM (Professional Video Monitor). Even if it claims to support Super VGA, the tube was only meant to display standard-definition broadcast video, so anything greater than 640x480 will probably be too fuzzy to be clearly readable.

50269349.jpg
 
compaqportableplus said:
I’m almost 100% positive the COMPAQ Portable’s internal CRT is NOT composite, considering it’s dual-mode and how good the color shading is. Also, the internal connector uses like 5 or 6 pins instead of two like the 5155. The 5155’s composite CRT has problems with certain colors causing text to be illegible. The COMPAQ doesn’t have this issue.
Click to expand...

The Compaq's monitor is indeed not composite, it has an analog video line for the grayscale and separate sync lines. But for the record, the reason the 5155 has that "trashed text" issue isn't really because of the composite sync (in theory a monochrome composite signal could be just as clear, as long as it's feeding a monitor instead of a TV with its various bandwidth traps, because the sync signals only matter in the blanking areas), it's because IBM just used the same CGA card as the desktop machines and didn't (permanently) disable colorburst on the internal connector. The CGA card does have a switch to turn off the NTSC color signals (ala 'mode bw80') but some software doesn't honor that setting and flips it back on again.

(It is also true that the color-to-gray translation could be a little better, IBM didn't make perfect choices in choosing the resistor ladder that produces the "luma" signals on the CGA composite output, but that's a minor issue compared to the colorburst trashing.)
 
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