Crosley Conductor CR73 Turntable "record cr66" Questions

What is the big knob in the record player area of a Crosley Cr66 http://www.manualslib.com/manual/704250/Crosley-Rochester-Cr66.html?page=8#manual

...CR66 4 in 1 record player and now my records sound distorted and far away It might be that you have caused an earth wire to the cartridge to come off or loose. Check the connections to the

...CR66 Rochester 5 in 1 Entertainment Center with auxiliary input, AM/FM Radio, tape, CD Player Once the turntable mode is selected picking up the arm and moving it to the record should start the deck ...

...but was on all the time, never shut off, but as long as it turned I was fine. Got home to play some records and it wouldn't play. Directions say to turn arm to the right until a click, which starts ...

...cr66 Rochester that plays records very quietly even at highest possible volume. Cds and radio can go to full volume so I know its not the speakers. Any idea what the problem could be? There are 3 ...

CR66 model,we cannot get the turntable to activate,it wont turn!It is brand new! so I dont understand whats wrong? we hear a click sound but nothing happens please help ty Bill remove the rubber plate