Having several variants of these watches with this particular movement, and being a fairly good tinkerer, I do my own repairs within my limitations. These particular movements give a warning when the battery needs to be replaced. The warning is the typical "Seiko low battery two-step" The timekeeping second hand advances two seconds at a time. When the watch does this it is time to replace the battery. Despite being a complex movement, battery replacement is fairly easy and straight-forward, so it is not difficult at all.
Using the proper tools(case wrench or case knife depending on whether the watch has a screw-down or a snap-on caseback)remove the caseback.
This is what you should be looking at:
Once the watch is opened remove the battery. This can be done different ways. The way I do it is like this, gently lift the battery contacts(very gently as not to bend the prongs. One prong is the battery contact the other is for the alarm signal for these watches)slide the battery out of it's position either with your fingers or the aid of a pair of tweezers could be helpful.
Again, this is what you should be looking at:
Once the battery has been removed, check the contacts for signs of corrosion. If there are signs of corrosion or battery leakage, this needs to be cleaned out. This can be done using a small cotton swab and a little denatured alcohol. If at this point the corrosion or battery leakage looks severe, the watch should be sent to a qualified professional for service or repair. If there is little or no corrosion, once cleaned, you are ready to re-install the new battery. If the contacts were cleaned make sure they are dry before installing the new battery. The battery required for this movement is a SR-927/395.
Installing the new battery. This is done very much like removing the battery, only in reverse. Gently lift the contacts and slide the new battery into position positive(+) side up.
It should look like this:
After installing the new battery, the movement may or may not spring to life. If the movement does not start right up, do not dispair, it merely needs to be reset.
Resetting the movement. If the movement does not come to life after installing the new battery it will need to be reset. This is easily done by touching the "AC"(All Clear) contact with the positive(+) side of the battery. This can be done using a small gauge wire, paperclip, or fine point tweezers.
Once the battery is installed and the watch has been reset and is now running it's time to replace the caseback and reset the features of the watch. Usually when I re-install the caseback on any watch I open I like to put a little waterproof grease on the gasket. This keeps the gasket pliable and helps with water resistance. Resetting the features can be found by following this link:
This pretty much concludes this DIY tutorial. I do wish to say that I am not a watchmaker and I do my own repairs at my own risk. That being said, by following these instructions and the watch still does not work it should be sent to a qualified professional for service or repair.
Watch and pics are Dennis Lacey's. Graphics and link provided by Matt(aka.Crossfeed).