Joined: Jan Thu 01, 1970 1:00 am Posts: 611 Location: Marshall, Il. USA 62441
You tune these by pressing the button to enguage the tunin slug, then you use the screw on the front of the slug to set a station. The bottom button, when pushed, it enguages the manual mode, and you tune stations with the tuning knob.
These also usually require that the set is in fairly good alignment. So if you need the alignment instructions from the Zenith Service Manual send me a PM and I'll email you a copy.