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Thread: IBM 5155 Error 601, two beeps, no Floppy LED

  1. #1

    Default IBM 5155 Error 601, two beeps, no Floppy LED

    hello all,

    my name is Gregor, I am from germany (46 yrs old) and collect "old" computers...

    Today my IBM 5155 portable arrived - but there is a problem with the 2 floppy drives.

    I read in the forum and looked for similar errors, but my main difference is, that the floppy has no power.

    the RAM test is ok -> 640
    then i get 2 beeps
    and the error 601 - press F1 message
    after pressing F1 the system goes to basic

    i opened the computer and the floppys do not spin.
    i removed the controller, changed the cables, removed the powercable from the flooy but i always get error 601 with two beeps.

    any hints, what the problem is and how i can solve it?

    are there some settings which I can look at?

    thanks in advance

  2. #2
    Join Date
    May 2009
    Blog Entries


    Check the motherboard switches. Easy to accidentally bump one.

    Otherwise, could be a problem with the power cable or data cable being broken or a component on both floppy drives having failed. Using a multimeter to verify that the motor on signal will pass through the data cable might be a good check.

  3. #3


    thanks for the advices. I will do at the weekend. Can you tell me where i can measure this: "verify that the motor on signal will pass through the data cable "

  4. #4
    Join Date
    May 2006
    Melbourne, Australia


    Welcome to these forums.

    Lots of IBM 5155 information at

    In case you are unaware, note that the motherboard in the 5155 is actually an 5160 motherboard. That is why you may sometimes see people pointing you to 5160 information.

    Be aware that during the power-on self test (POST), that the POST only interacts with the first floppy drive (the one at the end of the cable), do not expect any activity on the second floppy drive (on middle of cable).

    See the 'Cable and Termination' section of [here], and verify that your setup is per that.

    Also, because the floppy drive in the middle of the cable is optional, perhaps you should disconnect it for now, just in case of interference from it. If you do that, then ensure that the remaining floppy drive is terminated.

  5. #5


    thx for the advices.

    I will do the tests at the weekend.

    hopefullyI will get the floppies working again

  6. #6


    Voltages are ok (5 and 12 V)
    But C56 is damaged. Could this be the reason?
    I think I need to extract the board now

  7. #7


    I read here that I can cut out the cap56.

    This didnt help. I still got the error message and no "LED" at the floppy. I controlled the jumper settings and the "data cable" between the controller card and the floppy. there are no problems
    the 5 and 12V at the floppy cable are also ok.

    any ideas, which i could try next?

  8. #8


    When i first got my 5155 one of the faults was both floppy drives were not working, It turned out to be the hub pulley in both drives were seized, With the belt on the motor could not turn the hub pulley. Worth checking on yours if you haven't already, Carefully remove the belts and see if you can turn the hub pulley by hand, They should turn freely and easily, Some lubrication got mine working again.

  9. #9


    2018-10-22 11_13_54-Window.jpg

    so this is the floppy A... any to do here?

  10. #10


    working again. a new controller solved the problem


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