# Battery Problem With New Old Seiko



## bughammer (Feb 10, 2005)

I wonder if anyone has an idea about this...

I just acquired a Seiko quartz with a 7N42 movement. Having cleaned it up it is a beautiful watch, but the come down came when I tried replacing the battery.

The second hand moves about 2 seconds and then stops dead.

Does this mean I need a high drain battery in the watch instead of the low drain one I tried, or have I just got a lemon? (Didn't think it mattered too much as the watch only has a date window).

The two second thing reminds me a little of the "end of life" indication on my other Seiko, but the watch did have a flat battery in it for a long time and has traces of rust inside.

I'd be grateful for any pointers!

Thanks

Kevin


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## julian (Jun 3, 2003)

I had this sort of trouble on a 7548 (?) Seiko diver.

The batter had at some time oozed some stuff out .I cleaned the contacts carefully and and replaced the battery with a new one from a Tandy store using the same ref. no as the old one .Still no movement .

A person on the SCTF advised me to check the voltage on the battery which was ,say 1.5 volts .He then told me that this movement required say,1.55 minimum to work properly .I got the battery ref. no. from Seiko and bought one ,checked the voltage and installed it .It worked .

Sorry I can't remember the voltage figures .I feel that another key factor here was dirty contacts.


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## bughammer (Feb 10, 2005)

Thanks Julian.

I did a bit more cleaning an lo and behold, the second hand moved. For twenty whole seconds!

Also, occasionally the second hand just oscillates on the spot with a high pitched whirr.

Let's hope it's just a speck of rust or something.

Not all that reassuring but I'll keep at it!

Kevin


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## Roger (May 17, 2003)

> A person on the SCTF advised me to check the voltage on the battery which was ,say 1.5 volts .He then told me that this movement required say,1.55 minimum to work properly .


A little bit of mis-understanding here, I think.

All batteries of this particular chemical composition will all have a nominal 1.5 volt rating.

If a particular cell has, say 1.55V, straight off the production line, it will not have that level for very long. Temperature and other factors influence the terminal voltage of a cell ( a 1.5V "battery" is a cell...several cells together make a battery).

It will very soon settle to 1.5v.

Just measuring the terminal voltage of a cell is a pointless excercise ( other that to establish that it is completely flat)...the voltage needs to be measured "under load". Any decent battery tester will incorporate a load resistor designed for that type of cell.

Roger


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