Q: S-Video composite adapter does not work

I have an Mini-DVI to S-video/composite/cinch adapter from apple that is supposed to work with my MacBooks. Actually I have two MacBooks, one from early 2009 and one from mid 2008 (both white, 13"). The point is: on the 2008 MacBook the adapter works as it should, on the 2009 MacBook it does not work. Do you have any suggestions?

I have another Mini-DVI - VGA adapter which works ok on both MacBooks.So it seems that the MiniDVI port is working on both computers and also the s-video adapter works on one MacBook. So from the hardware site it seems ok. 2008 MacBook runs MacOS 10.6.8. The 2009 MacBook has El Capitan installed (problem exites with Yosemite already). I am not aware that any drivers need to be installed.

thank you very much!