Couldn't be bothered getting out the old MBP's power supply, so I'm now charging it from the one belonging to the old MBA that I sold (with a new power supply) almost a year ago. It's charging because there's no spinning HD to consume power.
Otherwise the lower-powered charger would only be able to stop the charge from dropping.
It's all OK now. Must have been battery-related. I'm currently enjoying the "proper" Mac keyboard as used in the pre-unibody 2008 15-in MB Pro. Yesterday I swapped out a suspect SSD & popped in a new one.
Working well, I really love the old Mac laptop keyboards.
MBA is having coniptions, is stuck in a perpetual reboot cycle. Was OK six hours ago, when I shut down a web browser & closed the lid. Battery level was under 15%, maybe it'll come good with a bit of a charge in it.
Certainly hope so.
It's still rare to find traders in the USA willing to ship items here. So I'm happy with the thing I found today on Amazon: a waterproof, shock-resistant case for the 6th gen iPod Touch. Price: US$19.60, including postage. ETA here: March 16.
Strange how freezing a product can change the taste. A particular coffee-flavoured milk has a slight coconut taste in the background when served cold. Yet, when frozen & mostly thawed, it has a peppery taste. Of the two, I prefer the latter.
Today Gary Rosenzweig at Macmost.com released a YouTube video demonstrating how to use Terminal to change the location where screenshots are saved on a Mac. I tried it & it works quite well. But I don't need that method to achieve the same outcome.
Once upon a time (sometime between 2005 & 2007) I acquired a preference pane called (very imaginatively!) Screenshots. With this you can save screenshots to any one of 12 different formats 
and vary the location as you desire.
Naturally, that Preference Pane is no longer available, but I can report that it still works under Sierra 10.12.3.
@nitinkhanna Those two T6 screws are from an old HDD: They replaced others that were lost in the carpet pile last time I replaced the drive.
Operation successful. Pre-unibody MB Pro now boots from a SanDisk SSD instead of the faulty Kingston one. The hardest part of the swap was locating a T6 torx screwdriver.