Are you sure the playback on the Cam is functioning?
If that's not an issue, then do you have a remote (an original hopefully) for the VCR? Mine has to be set to the "input channels" via either the remote or the channel buttons on the VCR (not the one on the back that selects CH 3/4 output for the TV, the ones on front that control what TV channel is passed through the VCR). The common "historical" [feels weird to say that
] TV/VCR setup used the VCR (the antenna/cable was plugged into the back of the VCR's "Ant In" or "Vid In" port) to control what channel you viewed on the TV; and you always left the TV on either CH3 or CH4 (whatever setting corresponded to the selector on back of the VCR).
Try cycling through the VCR's channels and see if you can find something that says "input" or some other funky designation (mine says "L1" and "L2").
Ex: L1, L2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10...19...28...etc.