Graeme Cogger wrote:

1. "ATC" - I believe this is some kind of auto-tuning system - but
neither of the two controls ("select" and "off/on" pushbuttons)
appear to do anything, or make anything appear on the display.



Not sure about this, but you don't tune cassette decks!

You do.
At least you can adjust the bias for the best frequency response with
different tapes.
On mine this is achieved by pressing the Auto-tuning start button with
a recordable tape loaded.

--
Eiron

I have no spirit to play with you; your dearth of judgment renders you
tedious - Ben Jonson.