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Fixable IBM 5155?

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    Fixable IBM 5155?

    I bought a broken IBM 5155 a while ago, and cosmetically it's fine, but it doesn't do anything when I turn it on. I've taken some of the boards out and one of the batteries has leaked, and a few capacitors exploded. I have a very limited understanding of these old computers, but I would really like to get it working. Do you think there would be any chance of that happening? would replacing the broken boards fix it, or could it be the power supply?

    #2
    Start with the PSU and work out from there. PC/XT (5160) motherboards come up on here fairly frequently.

    Comment


      #3
      Please learn to solder and repair electronics. Please don't be one of those who operate on the basis of "if it doesn't work right away, it's garbage". Capacitors age and can be replaced. Power supplies use capacitors and if anything, are more prone to that type of failure.

      The bottom line is that you can probably resurrect it with a little determination--unless it's been through extreme conditions, of course.
      Reach me: vcfblackhole _at_ protonmail dot com.

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        #4
        If you take photos of the problems I'll help you all I can. I'm about 30 miles from Bristol.
        https://www.micromuseum.co.uk/

        Comment


          #5
          The quick and simple answer is yes it can likely be fixed. Just a little practice work and determination and you can replace those bulging capacitors and likely fix the problem for minimal cost. Chris's help will probably be a good experience too.
          Looking to acquire: IBM 5100, Altair 8800

          Comment


            #6
            Sure, I'll take some pictures and put them up tomorow. From what I remember, one of the boards was fine, one had exploded capacitors and one a corroded battery. From what I could see the rest seemed fine, but I didn't delve any deeper than that... I think I need a screwdriver with a different bit to get to the rest.

            Comment


              #7
              from the sounds of it you may be dealing with an expansion board that went south. An old RTC board perhaps? Try taking out all the board BUT the graphics card and start from there, pics will help greatly though
              Nothing beats the roar of a 36yr old drive coming to life after a decade in storagg

              Comment


                #8
                I started to take it apart again, but I only got as far as the cards and one floppy drive (it's got two, but one is different). I'll get the motherboard out over the weekend, but I could see the 8088 in the back

                So here are the pictures (sorry some of them are a bit blurry):

                P5032180.jpg

                The Computer itself, with two floppy drives

                P5032183.jpg

                Here's how the boards are laid out. The thin cable coming in from the left goes to the far left board (board 1), the two coloured ribbon cables are coming from the middle board (board 2), going out the back of the computer. One of the thick ribbon cables is coming from the smaller board on the right (board 3), and goes to the floppy drives. The 8088 is in the top left behind the cables (there is an empty slot for a similar size IC beside it, I don't know if there's something supposed to be there.

                Board 1

                P5032196a.jpg

                Here's a close up:
                P5032197.jpg

                The exploded capacitor is the only fault on that board, and so far (I haven't taken it apart fully yet) the only exploded capacitor.

                I can only attach 5 files a post, so I'll do another one in a minute. Sorry for the long posts :P
                Attached Files

                Comment


                  #9
                  That capacitor is a tantalum--they detonate on old gear with remarkable regularity. But that isn't going to keep your system from booting, so keep digging.

                  If I'm trying to work on a system, I'll take it apart and reassemble the boards, peripherals and power supply on a tabletop, so I can see what's going on.
                  Reach me: vcfblackhole _at_ protonmail dot com.

                  Comment


                    #10
                    Originally posted by CannedBread View Post
                    but it doesn't do anything when I turn it on.
                    This could indicate that the fuse in the power supply has blown, because of a short circuit that could have been created by one of the exploded or damaged capactitors.

                    Comment


                      #11
                      While I haven't used a 5155 PSU, the power supplies normally have an auto-cutoff if their outputs are shorted. You can tell if this is the case because when you turn them on you see the fan nudge a little but not spin. To keep it alive, my 5160 board has had to have ~4 capacitors removed now.

                      Just to clarify, is the system turning on but not displaying anything, or does literally nothing happen when the power switch is flicked?

                      p.s. http://www.minuszerodegrees.net/5150...iag_config.htm (test at bottom is extremely useful, still applicable to a 5155, would recommend you follow it through)
                      Last edited by SpidersWeb; May 3, 2012, 12:48 PM.
                      Twitter / YouTube

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                        #12
                        Originally posted by Chuck(G) View Post
                        Please learn to solder and repair electronics. Please don't be one of those who operate on the basis of "if it doesn't work right away, it's garbage". Capacitors age and can be replaced. Power supplies use capacitors and if anything, are more prone to that type of failure.

                        The bottom line is that you can probably resurrect it with a little determination--unless it's been through extreme conditions, of course.
                        I really missed the "Like it" from facebook

                        Get the PSU disconnected from everything, and turn on the PSU, take a look if the FAN spins, if not, then it's time to disassemble it, and try to fix. If it spins, then it's time to begin to repair that dead components.

                        Comment


                          #13
                          I can't remember weither or not the 5155 has a fan
                          If it doesn't then you can use a sacrificial hard drive (make sure it's a hard drive you don't like, just in case).
                          If it does, then ignore this post :P
                          Twitter / YouTube

                          Comment


                            #14
                            Originally posted by SpidersWeb View Post
                            I can't remember weither or not the 5155 has a fan
                            If it doesn't then you can use a sacrificial hard drive (make sure it's a hard drive you don't like, just in case).
                            If it does, then ignore this post :P

                            Whops, I didn't think about this... One time I grabbed a 5155 Clone around here, and there was a fan on him... my bad.

                            Comment


                              #15
                              yeah I'd forgotten to check that as well lol
                              it might do, I just can't remember.
                              Twitter / YouTube

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