If by "adapter" you mean the coaxial antenna jack on the back of your set, you can fix this with a VCR. Here are two methods, depending on how you are receiving cable channels (with or without a box).
1. WITHOUT A BOX: Connect the cable wall jack to the VCR antenna input. Connect the VCR composite (yellow-red-white) output to similar jacks on your TV. Select that input with your TV's remote. Change channels on the VCR.
2. WITH A BOX: Connect the auxiliary RF output jack on the cable box to the antenna jack on the VCR. Connect the VCR to your TV as above. Set the VCR on channel 3 and leave it there permanently. Option your cable box (through its menu) to output analog ch. 3 at its RF jack (it's probably there already). Change channels with the cable box remote.
I've done this both ways and it definitely works. Good luck.