Forum Rules and Etiquette

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hello new owner of a ibm5155

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    my knowledge of computers is mostly having new custom made desktop computers and small upgrades to my laptop. things like psu and rifa are all new to me. in short this is unknown to me.

    older computers i known about are ones that had a keyboard and computer together. the monitor and the B drive where on the outside connected.


      how can i remove the cpu correctly?


        Those pics look really nice! It looks pretty clean inside.

        Originally posted by al1980 View Post
        how can i remove the cpu correctly?
        FIRST Ground yourself. There are a lot of static sensitive parts in there.
        The important thing when removing the cpu is that you don't bend any pins. The best way to accomplish this is to remove the motherboard(it can be done with the motherboard installed, but you have better access with it out of the case) and use an IC extracter. Before removing the moterboard, all expansion cards and both floppy drives must be removed(you need to clean and lube the carriage rails anyway). A 1/4 inch drive ratchet with the appropriate socket helps when loosening the inner floppy scews. When you put the V20 in, be carefull to align the pins with the holes in the socket before carefully pressing it all the way down into the socket (the notch on the end of the IC must line up with the notch on the socket.). Don't push to hard. If it doesn't go fairly easy, you probably don't have it lined up correctly and you'll bend pins if you force it. Again this is difficult if you don't remove the motherboard. Radio Shack makes an IC inserter that helps but you still have to align the pins. Your great pics should help you figure out how to put it back together.
        Last edited by ibmapc; September 17, 2012, 08:16 PM.


          What do you guys recommend for lubricating the rails? Also do you actually do this regularly? To be honest I have never done it and even my 5150 drives (which are original) continue to run w/o a hitch. I know all oil will break down, get dirty, get sticky, but if its working fine maybe it is a case of leaving well enough alone?
          Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!


            Originally posted by Shadow Lord View Post
            What do you guys recommend for lubricating the rails?
            I use isopropyl alcohol to clean then very small amount of silicone lube with a Q-tip.
            Originally posted by Shadow Lord View Post
            Also do you actually do this regularly?
            Maybe once every 15 years.
            Originally posted by Shadow Lord View Post
            To be honest I have never done it and even my 5150 drives (which are original) continue to run w/o a hitch. I know all oil will break down, get dirty, get sticky, but if its working fine maybe it is a case of leaving well enough alone?
            The floppys on my original 5155 started acting up about 5 years ago and cleaning and lubing the rails fixed it right up. I also bought a 5155 from ebay a while back with non functioning drive A. Cleaning and lubing the rails fixed it right up.
            The Qume drives tend to get sticky rails. Maybe the stepper motor is a little weak or maybe the carriage rails aren't well designed or lubricated in the first place.


              On the card in slot 2 is a barrel shaped NiCad battery. The purpose of the battery is to keep the real time clock (RTC) going when the computer is powered off.

              One of the photos suggests to me that it is leaking. If it is leaking, then you need to deal with that before the leakage causes damage. There may already be some damage. After the battery is removed, the suggested (by Druid6900) method of neutralising the NiCad leakage on the card is by the use of vinegar and water.

              The computer can function without the battery. Without it, the date/time will be lost when the computer is powered off.


                For the time being I have removed the card from slot 2 . I seen some corrosion from the battery leak on to the card. IMAG0164.jpg thank you for pointing this out to me


                  Originally posted by Shadow Lord View Post
                  What do you guys recommend for lubricating the rails? Also do you actually do this regularly? HiHi
                  The 5155 uses the same floppy drives as the PCjr which seem to need cleaning more often.
                  I use CRC Silicone spray, but I don't spray it onto the rails directly. I spray some on a Q-tip
                  and wipe the rails down with a light coating.


                    do you have pictures to show how to clean the rails? and what are rails. sorry i don't know much about this.


                      Originally posted by al1980 View Post
                      For the time being I have removed the card from slot 2
                      Also check the motherboard right below where that battery was when the card was installed.
                      I have a couple of motherboards with damage because the battery liquid dripped onto the motherboard.
                      The boards still work though


                        here is some pictures of the card form slot 2. i have no idea who makes it. is there better cards i can get?


                          Just chop off the battery and clean it up.


                            Originally posted by al1980 View Post
                            here is some pictures of the card form slot 2. i have no idea who makes it.
                            MF-100, made by Diamond Flower.
                            Details at
                            One on eBay at item 300764702557


                              Originally posted by al1980 View Post
                              is there better cards i can get?
                              Not really. The 5155 has limited space for cards, and so one card providing many functions is desired.
                              The MF-100 has RAM (to bring total RAM to 640K), RTC, game port, parallel port, serial ports.
                              An example of a different card that provides the same functionality is the SixPakPlus, made by AST.

                              Originally posted by al1980 View Post
                              One on eBay at item 300764702557
                              Warning: No RAM fitted.
                              Warning: "Sold not-working as parts."


                                Hi Al,

                                I didn't notice anything above about cleaning the floppy drive heads. In addition to cleaning and lubing the rails, it's a good idea to get a drive cleaning kit, which has a floppy diskette made of fiber, onto which you apply a few drops of cleaning fluid. Running that floppy in the drive cleans the head. This can also be accomplished with a Q-tip and some isopropyl alcohol, but I've not been able to do as thorough a job as quickly that way as with the cleaning diskette.

                                When I bought my 5155 and immediately experienced problems with my floppy drives, I used the cleaning kit to get them functioning again. I later followed up on the rails, and subsequently I replaced the 5.25 in. 360kb floppies with 3.5 in. 1.44mb floppies. I also have a prototype of pearce-jj's CF board with a 128mb CF card that serves as an HDD.

                                Regarding software for the 5155, what sorts of things do you want to do with the computer... write, create spreadsheets and databases, play games, or what? You can do all those things on the 5155, within the limits of its CPU speed, memory, storage, and 9 in. monochrome display.