Seiko Kinetic Battery Replacement (5M42, 5M62)

My father had an old Seiko Kinetic sitting dead in his drawer.  It is a 5M42 which was an early generation model with a capacitor and a 14 day power reserve.  The current calibers of today (5M62 for example) have transitioned to rechargeable batteries with 6 months or greater power reserves.

I offered to try to fix it for him.  I typically don't do repair jobs for people as I break the watch more often than actually fixing it.  But since this one was sitting unused for at least 10 years and I have since replaced it with several other watches for my father, I thought there's be no harm in the potential failure of fixing this kinetic.  Since I could get the second hand moving with some shaking of the watch, I figured all it needed was a new power cell.

A common problem with the Kinetics, especially the early models, was power cell failure due to frequent depletion.  Unlike solar charged watches which can maintain full charge just sitting on a dresser or watch box provided it sees some level of ambient light each day, the kinetics obviously require activity to keep it fully charged.  This poses a problem with owners who either own multiple watches or just choose not to wear the watch on a regular basis.

Finding a new replacement cell was pretty easy.  I have purchased from BatteryBob in the past and was happy with the service so I checked there.  Sure enough they had the Seiko genuine replacement kit for less than $20 US.  One important note about the kit is that it can be used for not only the current calibers, but will also convert the older calibers to the 6 month power reserve battery.  The replacement part is Seiko number 30235MZ.

So I'm not going to provide a detailed walkthrough of the process.  There is already an excellent tutorial posted on the PMWF which I used and I will simply redirect you there by clicking HERE.

Following the tutorial I was able to successfully remove and replace the power cell in about 30 minutes. And this with a cheap set of tools I bought off eBay several years ago.  The most challenging steps were the simple removal of the caseback as it was really tight and the removal of the rotor as the screw head has a very shallow groove and my screw driver could not get enough bite.  Other than that things were easy.  Just go slow, work without any distractions and pay attention to how everything is connected and you can do it too.  One word of caution is that the screws are very small and easily lost.  Unfortunately these don't come in the replacement kit, so be sure not to lose them.  Also take EXTREME care around the copper coils.  One nick of the thin copper thread and you're done.

Below are some pictures I took of the process.  They aren't very good and were only to be used as a reference for me with reassembly, but I'll post them here as there aren't enough pictures of Seiko kinetics on the internet. A few surprises to me were that the 5M42 has 6 jewels and the massive size of the copper coils.  Other than that it was basically a utilitarian looking movement which was never intended to be seen by its owner.  Besides my pictures, HERE is a great read with some pictures of the 5M62.