My VCR will not display on my TV using s-video.

When I returned from vacation, my VCR would not display on my TV. I checked all cables, etc and everything was fine. I took it to the Repair Shop and he cleaned the unit and said it works fine. Of course, as expected, it still DID NOT work for me so I returned to the shop and told him to check the s-video connection I was using. He reported the unit worked perfectly using MY s-video cable on his TV. I re-connected the unit to my TV using the RCA plugs (and not the s-video cable) and it works fine. What is going on?