I've got a fleet of 'scopes, one of the friskier vessels being a Yokogawa 150MHz digital 'scope, DL1540. Decent 'scope, 4-channels, FFT, GPIB (which I don't use), saves waveforms in .BMP on floppy(!).
(I don't know mine's birth year, but Yokogawa's website says they retired the line in 2003, for whatever that's worth.)
Its 1/2-AA Li RTC/backup battery just finally died Thursday, so the 'scope was losing its time, date, configuration, and setup data every power-off. And displaying an error message on boot. Not a big deal, but slightly tedious.
Replaced the dead cell on Saturday with a AA-sized Li backup. Inside, quite a tight bundle of interconnected boards in a heckua awkward tight space. Lots of fast ICs with heatsinks, in a carefully- planned stream of high-velocity air.
Back in business. The first Li lasted >=13 years, so I figure I'm good for at least another 20. :-)
Cheers, James Arthur