The clock I have is a black-light clock radio similar to the Sony Digimatic at this URL: http://www.radiomuseum.org/r/sony_digimatic_tfm_c690w_tfm_c.html

I've tried just setting the alarm set dial to the right time and then pressing the alarm, but the alarm just goes on immediately. The sleep knob works independently of the alarm, and the reset alarm (snooze) button just delays the alarm for 10 minutes.