Seiko 7A38 - by the numbers

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Forum Home > Parts Info, Tech Tips and Tinkering > 7A38 chronograph problem .

rogart
Member
Posts: 19

Hi all

New member here hopping to get some help :) Have a 7A38 that is behaving strange? Change the battery and everything is nice. But after a while the chronographe starts. Only thing that could fix is to take the battery out and put it back and it's working again. Could be a day or it's happenig right away? Like random? Have any clues what the problem is? The pushers works. Watch runs perfect otherwise. 

March 22, 2016 at 6:06 PM Flag Quote & Reply

rogart
Member
Posts: 19

Wrong part of the forum? No answers yet? I am getting the watch next week. So i will have a closer look at it? Could be oxid maybe? The owner says its very anoying? 

March 24, 2016 at 12:16 PM Flag Quote & Reply

donwatch
Member
Posts: 566

Roger, it could be a stray signal to the circuit board.   Caused by battery leakage or moisture.   Yes, oxid---probably need to take out board for cleaning. 

March 24, 2016 at 1:19 PM Flag Quote & Reply

Seiko7A38
Site Owner
Posts: 12380

Also wrong part of the forum, really, Roger. :/

It might better belong here: http://www.seiko7a38.com/apps/forums/show/6600711-Parts-Info-Tech-Tips-and-Tinkering

Subtitled: The place to ask questions; hopefully get some help - and share advice.

I'll move the thread there presently. ;)


March 26, 2016 at 8:10 AM Flag Quote & Reply

rogart
Member
Posts: 19

Great thread. Have been suspecting there are fake batteries out there. Always buy my batteries from the same place. Like GP batteries. 


I am continuing this thread here instead .http://www.seiko7a38.com/apps/forums/topics/show/13328826-7a38-chronograph-problem-

Got the watch today. The watch is running nice and works okay.It.s when the chronograph is running that things happen. After a while the subhands stops and only the big chronograph is running. It stops after 10-20 minutes of running the chrono. The movement is nice and clean and has no corrosion or haven't got any leaking batterys in it's history. 


April 4, 2016 at 4:23 PM Flag Quote & Reply

Seiko7A38
Site Owner
Posts: 12380

Roger.

The 1/10s sub-dial (RH) hand should stop spinning after 10 minutes have elapsed. It's an in-built energy saving device.


April 5, 2016 at 3:59 AM Flag Quote & Reply

rogart
Member
Posts: 19

Thanks for moving the thread to the right place. I found the problem:) Now it's working as it should again. Have no idea where all the oil comes from? The owner doesn't now either. This is how it looked under antmagnetic shield and under the circuit board .

 

The last picture is probably the answer to the chronograph problem? 

Could the owner have clean the outside of the watch with some oily stuff? It looks like it's has entered throught the pushers? 

Or oiled the pushers? Should probably need to be serviced soon but it's working for now. 

April 5, 2016 at 2:34 PM Flag Quote & Reply

Seiko7A38
Site Owner
Posts: 12380

Roger.

Looking at your photos (and the amount of oil present), I'd suspect someone opened the back of the watch and gave it a quick squirt of WD-40. Maybe as a shortcut to a service, or to clean up some rust / corrosion on the anti-magnetic back-plate. I'd get it mopped up as best you can, ASAP. Rodico is the ideal cleaning media, but if you don't have that, dab it off carefully with something absorbent - kitchen paper towel or tissue.


April 6, 2016 at 3:36 AM Flag Quote & Reply

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