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Thread: Working on some Compaq portables - tips/tricks?

  1. #11

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    Quote Originally Posted by JonnyGators View Post
    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....
    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/ont...k-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.

  2. #12
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    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.

  3. #13
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    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.

  4. #14
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    Thanks for the tip, I already have a set of replacement foam pads for the keyboard.

  5. #15

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    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.
    Compaq - “It simply works better”

  6. #16
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    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.

  7. #17

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    Quote Originally Posted by JonnyGators View Post
    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.
    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.

  8. #18
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    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....

  9. #19
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    Quote Originally Posted by JonnyGators View Post
    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....
    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.

  10. #20
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    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.
    Service manual

    http://www.minuszerodegrees.net/manu...ce%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.
    I finally replaced all the tantalum caps on the motherboard, video card, and floppy controller.

    Later,
    dabone

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