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Working on some Compaq portables - tips/tricks?

J

JonnyGators

Experienced Member
Joined
Mar 9, 2020
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168
Location
Attleboro, MA
So I have 2 projects currently going. 5 years ago a friend gave me a Compaq portable III he had, and I powered it on, it needed a boot disk, and in my basement it went for 5 years. I've decided to dig it out, and have setup my 98/XP machine with a 5.25" drive so I can now make boot disks for it, and have started booting it up and seeing what it can do. It powers on and boots, so that's a good start.

So now I'm hoping to do a little fixing up. It doesn't have an internal HD (or at least it doesn't have a working internal HD). I've read this link - https://rclassiccomputers.com/2017/08/08/portableiii/ - and it has good tips for the battery (not sure I'm clear about scraping holes and am worried about damaging things trying that, so.....better pictures might be good for that? Or a video? If such a thing is out there....but I can work without a battery for now) and for setting up an SD card as an HD.

I'm thinking....something like this for an ide to sd adapter? https://www.amazon.com/dp/B0026OYEEQ/ref=psdc_15874201_t1_B00H3CRJNY#
Does that look good, or any recommendations?

Also, I've noticed some graphics limitations on this model. I tried running the Compaq demos on a Compaq DOS disk. It fails to show the Compaq logo on the top of the menu, just a floating R that I think would have been in the upper right corner of the logo that they used text to do, and when trying to run things like space spiders or musical art, nothing displays on the screen. It's unable to draw things. It is running the programs, in the case of musical art, the text displays on the first screen, and the sounds work. But from what I've seen from articles on this machine, it appears it should have those capabilities to draw.

coolstuff4819.blogspot.com
My COMPAQ PORTABLE III 286 PC!
I'm typing this in WordPerfect 5.1, from 1989, on my Compaq Portable III PC, which I got a few days ago from the place I worked over the sum...
coolstuff4819.blogspot.com coolstuff4819.blogspot.com

I can't seem to find if there's an add on or accessory that makes that possible. Or if there's just something wrong with mine.

I don't have access to a CGA monitor at the moment, but am hoping to track one down soon, so I can test the CGA output on it and see if that makes a difference.

Also, it has 640k of RAM, which I suppose is good enough to play around some, but I know it had the ability to hold more RAM....but I don't even know what I'm looking for as far as RAM chips for a Compaq portable.

So I guess any suggestions on that would be appreciated.....more tips on the battery issue (I'm not that great at doing delicate work that has the risk of destroying things), the graphics issue, and whatever other things I should check out on it.


Project 2 is that I finally tracked down an original Compaq portable. When flipping the switch, the fan hums to life. But that's about it. After opening it and reseating cards, I did get it to beep once and then the light for the 5.25" drive came on. No display on the screen. Never gave up and turned out the light. I tried again now that I have a boot disk, but now I can't get it to beep and turn on the light, just turns on the fan. I don't even know where to begin with something like this. My normal methods of troubleshooting on modern stuff would involve swapping out parts with known working parts.....but I don't have access to spare Compaq portable motherboards and cards. I watched a video on youtube about a Compaq portable restoration, and while it was fun to watch, all that left me with is that it's helpful to have friends that just happen to have working parts hanging around that they can give you. So.....yeah.....not sure how to go about starting to get that to work, but I intend to have a fully working Compaq Portable one way or another. Suggestions?
 
JonnyGators said:
I'm thinking....something like this for an ide to sd adapter? https://www.amazon.com/dp/B0026OYEEQ/ref=psdc_15874201_t1_B00H3CRJNY#
Does that look good, or any recommendations?
Click to expand...
I would recommend a DOM over what you have in mind.

1) No adapter necessary -- it plugs directly into the IDE header.

2) It's more compatible and therefore way less hassle to configure.

BTW, where are you located? Your Profile conveniently holds that info so you don't have to mention it every time you post a message.
 
Ok, cool. One is on it's way, and that should get me on my way to furthering the work on the Portable III.

Meanwhile, on the Portable, I got it opened, and determined it was a power issue. Even with all cards out, and all drives disconnected, I found that the red light on the mobo would only blink briefly when turning on the power supply. I got to the power connector to the mobo, and took some measurements, and I don't know what is supposed to read what, but nothing read at 12, but some read at 2.5 or -2.5. I think it's safe to say the power supply needs work.

I took the cover off of the area covering the screen and power supply to take a look. There is a bunch of white gunk around some of the components, not sure if that's adhesive to hold things in place, or residue from something going bad. Anyways....at that point, it was late, and I put it back together for now. I'm not sure how to get further into it and get the power supply out of there, and I also don't have much in the way of info or schematics, I'm just digging in and looking around really.

What's the next step on this? Could someone point me to schematics or more detailed information? Any pictures/video out there of power supply work being done on these? I think if I could get the board out of the case, I probably could handle a few capacitor replacements.
 
My apologies if this is a repeat post, I think I accidentally clicked on an X that deletes the post while pending approval.


Thanks for the advice on the Portable III, I've ordered a module and will work on that.


Meanwhile, back over on the Portable, I got a bit further. I dug in and determined that the mobo wasn't getting power. I measured the contacts off the power supply and found values that I believe are low. Nothing measures at 12. I took the cover off the monitor/power supply area, and found some components covered in white residue, not sure if that's adhesive, or residue from something gone wrong. At that point it was late and I put it back together.

I could use some schematics for this if they are available anywhere, and if anyone has any experience working on the power supply on a portable, advice would be appreciated, I'm not sure how to get the board out of there. If I can get the board out and get my hands on some schematics, and specifications on what the pins are supposed to read, I should be able to handle replacing a few capacitors and getting the power supply back to working order.
 
Geeze, not much in the way of interaction around here, is there. Not much for help around these parts.

I did get a DOM on the Portable III. Not really a great option though, there's not much for clearance on the port on the motherboard, I had to buy an IDE extender cable to act as an IDE cable so I could install the DOM in a place where there's more space to hold it. But now I'm finding that when getting into the hardware setup, you have to select a specific disk type, and a 16GB modern module isn't exactly a HD type that Compaq was anticipating in the 80s. Am I stuck? How do I get this machine to recognize this module?

Anyone out there know anything about working on 80s PC? Please?
 
Using a DOM on a Compaq portable? AWFUL IDEA!!!!!

No clearance for the module to fit on the board!

The system settings require a disk type number.....NONE THAT ARE COMPATIBLE WITH THE DOM!!!!

Heck, on a more modern machine, I have the module connected, trying to do a DOS 5.0 install (which is a reasonable OS to use on a Compaq Portable III), FDISK DOESN'T SEE THE MODULE AT ALL!!!

COMPLETELY INCOMPATIBLE!!!!!

AWFUL SUGGESTION!!!

Anyone around here that knows how to work on these machines that could offer any useful advice?


This forum so far has been pretty useless......I can't even post anything without it taking days to show up, and then no one around here seems to want to respond, or make a few vague suggestions that are completely off.
 
Well, I managed to get windows on it...
I'd show a picture.....but the forum said it exceeds the file size, so no picture for you!

Managed to get the 40MB hard drive to work. Not sure for how long though, but it seems to be the only option since I can find no way to select a type that will work with any modern device, and no one around here seems to be able to offer much in the way of information as to how it could be done....
 
JonnyGators said:
Well, I managed to get windows on it...
I'd show a picture.....but the forum said it exceeds the file size, so no picture for you!

Managed to get the 40MB hard drive to work. Not sure for how long though, but it seems to be the only option since I can find no way to select a type that will work with any modern device, and no one around here seems to be able to offer much in the way of information as to how it could be done....
Click to expand...

It's good to hear you got the Portable III working again. Since your were able to get Windows installed, I assume the plasma screen is functional. Those are usually the worst components to go out - not much you can do but hope to find a used working one. As for the DOM, it really is the right answer. Won't be a simple drop-in replacement, but you can get it to work and you will be glad you did. Back in the dark ages, PCs had to have tables of the available drives in ROM. It took way too long to fix that nonsense, but trying to match a more modern drives to those old drive parameters is hard, not to mention a waste of the bigger drive sizes. Look for a drive overlay utility like OnTrack: https://www.philscomputerlab.com/ontrack-disk-manager.html
or EZ-DRIVE: https://www.youtube.com/watch?v=8LzCB6kDVC8

I use a DOM and OnTrack on my Compaq Portable 386. Makes for a very nice and fast setup.

As for your original Portable's power supply, that could be a messy fix. You *might* find a working one parted out from a machine on ePay, but don't expect it to be cheap. Probably worth your while to at least disassemble and clean up the power supply and look for anything obvious. They are nice machines, and very compatible with the IBM PC. It can even run the litmus test: the 8088 MPH demo.
 
Cool, thanks for the suggestions. Yeah, the screen works nicely on the Portable III. It does have 2 black lines on the right area of the screen, but it's still functional. I suppose that could be bad wires in the wire bundle that connects that monitor....but digging into that might do more harm than good, so I'm leaving well enough alone for now. I'll check out those solutions for the DOM, I figure the original hard drive is on borrowed time, so I plan on coming up with a modern storage solution eventually.

The original portable, I've recently received further suggestions on what to check there. Someone has suggested a few capacitors on the mobo that typically go that cause the problems I've been seeing - https://imgur.com/a/JjsaB. I'm struggling to figure out how to get the mobo out though, but if I keep removing screws I should eventually figure it out. The first computer I ever laid hands on was a compaq portable, so I'm quite determined to have a working one in my collection.
 
If you get the Portable I working, be prepared to replace all of the foam pads under the keyboard keys. I've yet to see one that didn't have rotted foam pads in the keyboard. I'll type OK at first, then the keys will stop working one after another. Just about the most tedious repair I've had to do myself. I've never seen where anyone manged to get any other keyboard working with a portable I. Besides, nothing else would fit on the case bottom like it does. I wouldn't have picked the Portable I for someone new to vintage computers. It's hard to work on, and is jam packed with proprietary components.
 
The Portable is really not that hard to service. You just have to pay attention and use some common sense.

For example, there is NO NEED to remove the plastic casing from the frame to remove any of the internal components. I’ve seen some people do that, but it’s 100% unnecessary.

Yes, they do use proprietary components, but can you name a portable computer that doesn’t?

To remove the motherboard, there is a small cover on the bottom-side of the machine (under the main outer panel) which lets you access the connectors to the motherboard (power, keyboard and speaker). Unplug all of them. Then, there is two screws on the top that you remove, and the motherboard slides out. Hope that makes sense.

The Portable is definitely worth your time to repair. They are the absolute best 8088 luggables in my opinion.
 
Ok, so here's where I'm at with the portable. I did manage to get the motherboard out, but the suggested capacitors to check visually look ok, no obviously blown capacitors. But, I turned my attention back to the power supply, because I really felt that I wasn't getting the right readings there. At this point, the power supply is completely removed from the case, not connected to anything, and the correct voltages are labeled near the pins. Many of the pins are not reading the correct voltage. The power supply definitely has issues. Unfortunately, I do not have the capabilities to work further on this, which leaves me stuck needing the services of someone that can find and fix a problem on the power supply, or build some sort of replacement that provides the correct power and will fit in the same space.

But I've yet to find the right place to actually find anyone capable or willing to help.
 
JonnyGators said:
Ok, so here's where I'm at with the portable. I did manage to get the motherboard out, but the suggested capacitors to check visually look ok, no obviously blown capacitors. But, I turned my attention back to the power supply, because I really felt that I wasn't getting the right readings there. At this point, the power supply is completely removed from the case, not connected to anything, and the correct voltages are labeled near the pins. Many of the pins are not reading the correct voltage. The power supply definitely has issues. Unfortunately, I do not have the capabilities to work further on this, which leaves me stuck needing the services of someone that can find and fix a problem on the power supply, or build some sort of replacement that provides the correct power and will fit in the same space.

But I've yet to find the right place to actually find anyone capable or willing to help.
Click to expand...

get at PICO ATX PSU and an ATX-AT adapter. preferably one that can provide the -5v, not super necessary but better if possible.

then chop the AT connectors off and wire the appropriate voltages to the Compaq motherboard power connector. boom.

cheap (ish) and reliable solution. This is what I did for a Tandy 1000 machine that had a damaged PSU. it works great.
 
Interesting suggestion. What I'm finding online accepts 12v, so I still need to get something small that can go from ac to 12. Plus, if I want it to still act authentic, I still need to get power to the power supply fan, which has jumpers to throw the AC over to that. Also, how does the built in CRT get powered, that's going to need to have enough power.....not sure I have all the knowledge I need to build something that will work properly....
 
JonnyGators said:
Well, I managed to get windows on it...
I'd show a picture.....but the forum said it exceeds the file size, so no picture for you!

Managed to get the 40MB hard drive to work. Not sure for how long though, but it seems to be the only option since I can find no way to select a type that will work with any modern device, and no one around here seems to be able to offer much in the way of information as to how it could be done....
Click to expand...

On my Portable III 286, I swapped the dead 40MB drive for a 2GB Fujitsu drive I had lying around. I selected the largest partition available in the setup disk settings - 500MB I think - and it works fine to this day. Yes, it's wastes 3/4 of an old drive - but it got me up and running with a slightly faster drive and still with that authentic drive access 'tick' we are used to hearing.

Along with the Settings battery rewire, my Portable III has been working for the last 4 years maybe.

- oh, I have Windows 3.0 on it too - but without the media features as I only have around 1.2MB RAM on the thing.
 
Meanwhile, on the Portable, I got it opened, and determined it was a power issue. Even with all cards out, and all drives disconnected, I found that the red light on the mobo would only blink briefly when turning on the power supply. I got to the power connector to the mobo, and took some measurements, and I don't know what is supposed to read what, but nothing read at 12, but some read at 2.5 or -2.5. I think it's safe to say the power supply needs work.
Click to expand...

Service manual

http://www.minuszerodegrees.net/manuals/Compaq%20Portable_Plus_286%20-%20Maintenance%20and%20Service%20Guide.pdf



OK, on mine while I was fixing it, this was caused by shorted capacitors on the motherboard. The led coming on and shutting off means that the power supply is coming up, delivering +5 , then shutting down.
Check the power rails on the motherboard for shorts to ground.
Do this with either the motherboard removed from the computer, or all cards removed, and the monitor and drives disconnected from the psu also.


Here's some notes on my old thread.

Motherboard, shorts out the psu.
This I have currently swapped out with the working motherboard from the other unit.

Video Card, shorts out the psu.
Cutting a lead on the C51 gets the Video card working again.


Floppy Controller, shorts out the psu.
I ended up cutting a lead on all the 106 16 Caps on this board, then it started working again.
Click to expand...

I finally replaced all the tantalum caps on the motherboard, video card, and floppy controller.

Later,
dabone
 
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