I've just bought a second-hand cassette deck (without instructions
unfortunately) and am having a bit of difficulty figuring out some
of the controls. The machine is a Technics RS-BX646. The bits I am
having trouble with a

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.

2. Timer. By the power button there is a three-way switch marked
"timer", where the positions available are "rec", "off" and
"play." Again, I cannot seem to make it do anything!

Can anyone advise me what these are for?

Many thanks.