jvc dvd/vhs combo question


First of all, I hope this is in the right place, searched around and didn't find anything more suitable so thanks for any help.  I have a jvc dvd/combo player that is on a very basic setup.  It's used in a exercise area just for the player and the tv.  I have the coax cable coming into the dvd/vcr and then another coax into the tv.  The odd thing is that when we try to watch tv, all we see if the blue background from the dvd/vcr.  I have tested the cable directly into the tv and that works. I have also tested the other coax cable on another tv and that works.  I can see the channel numbers change on the tv (though I have tried all the tv/video functions) which leads me to believe I am on the right setting.  I also checked the setup to make sure everything was on catv.  One other thing to add is that this worked until a month ago and then one day, it didn't.  Any thoughts?  Thanks again for any help.