Hi,

I am new to this forum. I thought the old watches are dead, but they are not.

Well: almost dead. I whanted to reactivate my C-801 casio calculator whatch but I have removed the batteries years before to prevent them to demage the watch. Now I do not know anymore which type of battery is the right one.

Does someone know?

Thanks.

MadMax29

The module 133 takes two 391's.

Thank you.

it took a while but I have ordered 2 batteries and hope that the watch will start to work.

:-)

Madmax

And the clear plastic spacer which sits on top of the RH cell (if batteries are at bottom when you look at back) is absolutely essential to stop the cell shorting out.

If it has gone missing not too difficult to make one from a piece of paper or thin plastic (advantage of paper is you can write a message on it to remind you not to throw it away!).

Hi,

after 30 years the watch works!
Thanks for the help.

One thing that I remember bothered me in the past..

I seem not to be able to set the primary time to 24h mode.
When I use the DT its by default 24h but the day marker does not show up.
On eBay (item 150414139907 canada ) I saw a pic from a 801 that shows the day marker on DT mode. Am I missing something?