this more modern nondescript model reminded me of the fx-82.
it comes housed in a protective hard case, but this time the dual power is
supplied from button cells rather than 2 AA batteries.
it has a delete key!
and a few other additions over the, older, fx-85m
(presumably the super-fx wherever they are).
actually, i quite like this unit. its very useful in a general-purpose
kind of way that doesn't irritate or try cram in too many functions that
you never need.
these super-fx models were twin power. most of the time the solar panel
is enough to power the machine, but in low light conditions, the power is
supplemented from a tiny panasonic gr927 battery. eventually, the battery
dies and the machine will no longer work in low light conditions. to replace
the battery, you have to take the back off the machine. presumably, this was
not supposed to be necessary in the machine's lifetime.
to remove the back, unscrew the 6 tiny screws and carefully lift off the
rear cover. you will see the tiny battery.