I have both a GM1 and a GM5. My GM5 hasn’t had trouble keeping time when I change out batteries, but my GM1 needed the clock set every time the battery was removed.
So, I bought a bunch of those Panasonic ML-421S/DN Coin Cell Lithium Rechargeable batteries from Mouser, as they are slated to be discontinued. I just replaced the one in my GM1.
I have a lengthy video that walks you through the details of getting to the top P.C.B., which is much more work than it appears for the GM5. Here’s the link to that video:
I will do the same for my GM5 soon. In the GM1 video, I don’t show unsoldering and then soldering-in the replacement battery on video; but I’ll likely do that in the GM5 video. I repair a lot of electronics and found that a trivial task; but it might be more advanced than I thought for others. And, yes, these batteries are soldered directly to the board (by design).
These cameras are too good to let die on the shelf. Recently, I travelled to Australia with my GM1, GM5, and Sony RX100MK7. The GM’s got the most use, as they simply took the best pictures, effortlessly I might add, with the array of lenses I have for them. The RX was best for blogging and some minor shots here and there. But for the best pictures, the GMs kicked butt.
Although you can still get those batteries on Mouser. Do not buy non-Panasonic batteries, because you really don’t know what you’re getting. These are lithium-ion rechargeable batteries that are recharged by the camera’s battery; so unless you get the right kind of battery, it might work for a while but will not last. And the steps to replace that battery are something I’d rather do every 10 years.
If you follow the service manual, have a precision-tipped soldering iron (like a Weller Model #T0058770715 with a precision, round tip), and are a bit brave (at least with the GM1), I recommend replacing the battery as soon as you can. Use my video as a guide.
I’d also like to give a shout-out to Emily (https://www.microfournerds.com/) for her article on getting into Service Mode on these cameras. Also, her advice on lenses has been unparalleled except for my cousin who had an MFT and recommended the 14-140/3.5-5.6, which is almost permanently mounted on the GM5 now.
