Some time ago one of my colleagues at work showed up with a vintage calculator watch he just bought at an auction. This triggered me to check if my vintage Casio CA 901 from the early 1980’s would still work. The best thing about this watch was not only the calculator but it had a game included.

Unfortunately I did not remove the batteries some 30 years ago… Well, this caused some issues with contacts and some parts of the circuit board needed some touch up.

But at the end, after some intense checking of the circuits and some frustration along the way the watch is back to live and working nicely. Only issue is that you cannot set the calendar to a date beyond 1999. But who thought, that a watch like this would still be used in 2019…

4 Gedanken zu “Repairing my vintage Casio CA 901 calculator watch

  1. Hi there
    I got this casio ca-901 model watch from old box in the house and when i replace the battery it worked but the LCD display screen is damaged partially.
    Where can i get the lcd screen?
    Please HELP


    • Hi,

      maybe you do not need a new display and there is only a bad connection between the display and the contacts. Sometimes the zebra strip (not sure, if this is the correct term) between the display and the curcuit board has a bad connection. You can gently remove the zebra strip and clean the contacts, maybe it also does not connect propberly because it is loose on some areas.
      However, if the LCD display lookes like it leaked this will not help.
      Unfortunately I have no idea where you could get a replacement display other than from another watch.

      Good luck…


  2. Great! So don`t worry! Just go back to the future! 😉
    Filmemacher, Taucher und jetzt auch noch Uhrenmacher! Thomas, du bist einfach ein Allroundtalent!
    Liebe Grüße,


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