How old is the watch? It sounds like a battery issue if it keeps resetting. If you have already replaced the battery, did you perform an A/C reset?

 

Thanks For your reply
My brother bought it for me last year from amazon in Malaysia
The price of amazon was 50% cheaper than casio website

 

Perhaps you got a bum battery. I recommend replacing the battery and performing a ac reset on the module. There are videos on youtube, and plenty of people around here to help.

Sent from my SM-G981V using Tapatalk

 

Thanks
I'll replace the battery
I wish it works

 

Try removing the battery and waiting a minute or so then try another ac reset. If that doesn't fix it then replace the battery and don't forget the
ac reset on the new battery. Other than that, I have no more suggestions.

 

Try removing the battery and waiting a minute or so then try another ac reset. If that doesn't fix it then replace the battery and don't forget the
ac reset on the new battery. Other than that, I have no more suggestions.

Thanks for your reply
i did it,unfortunately not worked
but when i opened the cover,hold the back of it by hands it works correctly ,and when i screw it by screw driver after many many times i pressed the mode it resets to 12:00 again

 

Hi guys
I have a casio B640W
to adjust the time i press mode button,but sometimes it resets to 12:00
Month and day resets to 1 - 1
Please help me

Hi. I'm not clear about the steps you are taking to adjust time.
1.Adjust button should be pushed to put the watch in time setting mode.
2.Mode button then pushed to select the field (hours, minutes, seconds, etc) to be adjusted.
3.Start/Stop then pushed to adjust the numbers.

edit: If you don't have a manual one can be downloaded from the site below.
https://support.casio.com/en/manual/manualsearch.php?cid=009&MODULE=3294&submit=

 

Thanks for your reply, i'll download the manual to better understanding the routine

 

Ok, thank you.
You have had the watch for about a year. Has it worked correctly for most of that time?

 

Ok, thank you.
You have had the watch for about a year. Has it worked correctly for most of that time?

Yes,it show the time and date correctly, 1 minute in a month it goes back, i read the manual and it says that its normal

 

Hopefully a new battery will correct the problem.

 

I hope so
CR2025 is compatible or CR2016?

 

CR2016 is indicated the manual.

 

Thanks

 

Hi, did the new battery and AC reset solve the problem?.....I have the same issue with this watch.

 

Hi, yes, its working great!!!

 

New battery and AC reset might be the first thing i'll try. If an issue still persist, I'll try to make sure that all contacts within a module are seated properly. If you are not familiar or not feeling so comfortable disassymbling the module, sending it to Casio service center might be an better idea.

 

Hola chicos
tengo un casio B640W
Para ajustar la hora presiono el botón de modo, pero a veces se restablece a las 12:00
El mes y el día se restablecen a 1 - 1
por favor, ayúdame
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I have the same problem with a Casio F91W, I don't know if the piezoelectric was installed correctly and that has something to do with it. (I doubt the watch is original)