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Latest score: Compaq Portable 486c

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    Latest score: Compaq Portable 486c

    Just thought I'd share my latest score: The seemingly rare Compaq 486C.

    My brother donated this PC, he rescued it from the trash at his work for me. Thanks bro!

    It did now work when I received it. I turned it on and nothing happened. I did however notice a capacitor failure smell. I guessed it would be the power supply at this point. Sure enough after disassembly of the power supply, 4 leaky caps were found. None of them were bulging, but all of them were the same brand and value. Replaced them with new caps.

    Now when turned on it appeared to be booting but the LCD was just white with some horizontal lines. I thought: Great a portable that can't be portable because the LCD is fried. I figured at this point I would be junking it but I had to at least make an attempt to find the issue. So, I carefully removed the LCD panel and disassembled it. To my amazement every single surface mount electrolytic capacitor (10 or so) on the boards in the LCD had leaked and 2 through hole caps on one of the mini boards that was attached to one of the boards. I replaced all of them. Easy to remove them by just twisting them off - Check Youtube. I only slightly pulled 1 pad and was able to epoxy it down. Epoxy stands up to the heat when soldered and the fix worked great.

    Re-assembled, turned on and it worked! The screen was clear and crisp like it was new!

    I just wanted to post my experience regarding the LCD panel so people know that it is easily fixable since I couldn't find anything online about it. This maybe why there are so few of these left in the wild and If this experience helps anyone it's all good.

    In the end I upgraded the memory from 8mb to 24mb and the processor from 33mhz to 100mhz with an overdrive processor I had. I also added an internal sound card and The sound comes through the internal speaker because there was an existing input for just such a thing. Plus a 2GB hard drive was installed, upgrading from 200MB. This thing works great and was a fun restore.

    P1010734.jpg
    P1010733.jpg
    Last edited by norm8332; July 15, 2018, 07:54 AM. Reason: adding

    #2
    Great story, I love hearing about this sort of thing, and fantastic that the only issue were the caps. Every time something doesn't work for me from now on I'll check the caps first thing.

    Got to say, its a bit of an ugly thing in my opinion, but I'm jealous, as I would love to find or have unique items such as this given to me.

    Comment


      #3
      You lucky dog! I remember tearing one apart back in 1998 because I wanted to use its lcd screen for a project I was working on. (how I wish I kept that machine)
      Want to trade for a portable III with a perfect working Gas plasma display??? Just kidding, you hold on to that thing, they are hard to come by. Nice score.

      Do those curley keyboard wires suffer from the same ROT as the portable III cables?

      Comment


        #4
        Originally posted by cb2000 View Post
        Great story, I love hearing about this sort of thing, and fantastic that the only issue were the caps. Every time something doesn't work for me from now on I'll check the caps first thing.

        Got to say, its a bit of an ugly thing in my opinion, but I'm jealous, as I would love to find or have unique items such as this given to me.
        Yeah, It's the caps bad most of the time in just about anything I have found. I have a stock of them now for just such an occasion.
        Last edited by norm8332; July 16, 2018, 11:11 AM.

        Comment


          #5
          Originally posted by VERAULT View Post
          You lucky dog! I remember tearing one apart back in 1998 because I wanted to use its lcd screen for a project I was working on. (how I wish I kept that machine)
          Want to trade for a portable III with a perfect working Gas plasma display??? Just kidding, you hold on to that thing, they are hard to come by. Nice score.

          Do those curley keyboard wires suffer from the same ROT as the portable III cables?

          Thanks, yeah the keyboard cable is very soft, you could dig your fingernail into it. I'm just being extra careful with it. I loaded it with a bunch of games from the era, (early 90's) and windows 95 for a NIC I added mainly to transfer files. And a boot menu etc. because I prefer IBM DOS 7.0 over 95 DOS because it is very memory efficient.

          It's a fun little dos box to add to my collection.

          Comment


            #6
            Cool looking machine there, man. Also, it's amazing that LCDs back in the 1990's used capacitors. Beautiful display. Is it TFT or the other LCD type?
            Current retro systems:
            386/486DLC, AMS NotePro Plus DSTN
            Packard Bell Pack-Mate 28 Plus
            Toshiba Satellite Pro 410CDT, 2x IBM ThinkPad 380D (both TFT)
            iMac G3/600 Graphite, iMac G4/800 Lampshade
            YouTube channel: https://www.youtube.com/c/RetroPCUser

            Comment


              #7
              Hey Norm, that's just plain nice. Good luck with it.
              Surely not everyone was Kung-fu fighting

              Comment


                #8
                It looks like a tft. It has very sharp saturated color, good contrast and a decent viewing angle for the time ('91) that DSTN lacks. This was a apparently an over $7,000 machine when new.

                I didn't expect the LCD panel would contain capacitors either, but it is like an inch thick in it's bare form so I disassembled it. It actually uses two 1/2 inch diameter florescent tubes for the back light!

                It actually has a Wikipedia entry...well not exactly.. This machine was a 486-33 (66?), Color TFT LCD, 8MB ram before upgrades and dated 1991. This is a 486C, C for color i guess.

                https://en.wikipedia.org/wiki/Compaq_Portable_486
                Last edited by norm8332; July 16, 2018, 12:50 PM.

                Comment


                  #9
                  Very nice! Definitely need to find me one of these someday. I’m a huge Compaq fan (as If that’s not obvious by my username).

                  You have confirmed my suspicion about leaky caps being the cause of the very common “white LCD” problem on these.
                  Compaq - It simply works better

                  Comment


                    #10
                    Originally posted by Agent Orange View Post
                    Hey Norm, that's just plain nice. Good luck with it.

                    Thanks, I'm definitely having some fun with it. I missed some of these old dos games on real hardware

                    Comment


                      #11
                      Originally posted by compaqportableplus View Post
                      Very nice! Definitely need to find me one of these someday. I’m a huge Compaq fan (as If that’s not obvious by my username).

                      You have confirmed my suspicion about leaky caps being the cause of the very common “white LCD” problem on these.
                      I realize the machine is 26-27 years old but I have a 47 year old Sony stereo and many vintage computers in their 30s that all the caps were fine in. It may be a issue with the caps or the LCD design IMO that causes them to fail sooner than other vintage equipment. All the caps were leakers, no sign of pressure problems or bulging. They appear to short when finally dried out, dragging down the power rail supplied by the video card. A transistor on the video card got so hot it started desoldering itself, but I tested it and it's fine. I replaced them with 1 step higher voltage across the board.

                      I use all my machines periodically to ensure I'm keeping the alu oxide up in the caps. As many of you know caps need to be used once in awhile to be kept healthy.
                      Last edited by norm8332; July 16, 2018, 01:21 PM.

                      Comment


                        #12
                        Fascinating! I didn't even know there was another past the 386. Great find!
                        General Failure Reading Drive C -
                        Abort, Retry, Ignore?

                        Comment


                          #13
                          Originally posted by norm8332 View Post
                          I use all my machines periodically to ensure I'm keeping the alu oxide up in the caps. As many of you know caps need to be used once in awhile to be kept healthy.
                          I did not know about this. How often is once in a while? monthly, quarterly, yearly?

                          Comment


                            #14
                            Originally posted by cb2000 View Post
                            I did not know about this. How often is once in a while? monthly, quarterly, yearly?
                            It is usually buried in spec sheets.. Usage avoids the need for reformation. A few hours of on time every three-four years should keep them viable. It is best summarized here:

                            https://www.badcaps.net/forum/showthread.php?t=50530

                            Comment


                              #15
                              Originally posted by norm8332 View Post
                              It is usually buried in spec sheets.. Usage avoids the need for reformation. A few hours of on time every three-four years should keep them viable. It is best summarized here:

                              https://www.badcaps.net/forum/showthread.php?t=50530
                              Thanks for that, every few years is all good. I was a bit worried because some old things I have don't get turned on for months.

                              Comment

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