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In the broader context of the somewhat intimidating business of tackling seemingly complex watch repair and restoration projects, it is funny how something as prosaic as changing a watch battery can assume a significance far greater than the task demands. Three and a half years ago, I bought a Grand Seiko SBGV009, part of the 50th Anniversary Historic Collection released that year, and an homage to the Grand Seiko Self-Dater from 1964. That watch is fitted with the Grand Seiko 9F82A movement, arguably the finest quartz movement ever made. In addition to the phenomenal accuracy, the sealed body of the movement ensures that no additional lubrication is needed for up to fifty years (subject to one buying into the GS marketing hype). In contrast to a high end mechanical movement, routine service costs should therefore be negligible but you do still need to factor in the need to change the battery every now and then. A few weeks back, the seconds hand on my watch went into its two second jump routine, indicating that after three and a half years of ownership, the battery was finally in need of a change.

Seiko UK will charge the thick end of £65 to £70 for a GS battery change but of course, the reality of such an undertaking, even on a watch as lovely as this, is that the fundamentals are no different from a battery change on any other quartz watch. And so of course I am going to perform this minor operation myself. The first step is to buy the correct battery. I know that the factory-fitted battery will have been a Seiko SR920SW and for no rational reason, I wanted to replace like with like, rather than just ordering a Renata battery from Cousins. £2.95 and a couple of days wait, and I have in hand a correct Seiko-branded replacement.

With an hour free yesterday morning, I cleared the decks and set about the task. Before attempting to open the case back, I wanted to clean away three years of grime from around the case back edge to make sure nothing made its way inside as I unscrewed the case back. Next, I considered how best to open the case back without leaving any marks on the case.

I briefly considered using the giant case back opener used to such good effect in the previous post, but that would need the strap removing and so I thought I’d give my trusty Rolson a try first. With the case back protected by a clear grip seal plastic back, some gentle but firm anticlockwise torque applied, the back unscrewed cleanly, providing my first real life view of the 9F82A.

I was half expecting to be slightly underwhelmed by the installation but in fact, it makes for a pretty impressive sight, in spite of the extent to which the case ring that holds the movement in place partially shields the outer parts of the movement from view. The only slight disappointment was to note some smudges on the movement, particularly evident in the vicinity of the battery. Those Seiko watch ninjas are clearly not quite as diligent as one might hope in living up to their reputation for meticulous attention to detail.

The case back gasket was in excellent condition, only needing a clean and so I elected to re-use it rather than source a replacement.

I did take measurements though and will use them to track down the correct part in preparation for the next battery change in three years time. You will have noticed that the outside of the case back does not have the traditionally formatted serial number from which one can deduce the month and year of manufacture (this being a limited special edition). However, on the inside of the case back we find the number 46 printed in black ink. I deduce that this implies a manufacture date of June 2014, four months prior the purchase date.

With the case back threads and mating surface thoroughly cleaned and the gasket freshly lubricated we can remove the spent battery and replace it with the new one.

You’ll notice that I’ve placed the new battery at an artfully jaunty angle compared to the perfect parallel alignment of the original. I do so to reference the fact that I’ve not then left smears of watch oil on the surface of the movement!

With the freshly cleaned and lubricated gasket in place, it is time to refit the case back and conclude proceedings.

Turning the watch back over and I am pleased to see the seconds hand now ticking at a frequency of 1 Hz once more. I complete this humdrum little job by setting the time and date, strap it to my wrist and wear it for the first time since the clocks went back last Autumn.