Are you sure you local TV station is broadcasting NTSC ? There are only a handful of low power NTSC broadcasts left in the country - the rest have converted to digital.
Referring to the scematic I uploaded:
http://www.bobandersen.com/images/sc...o/tv390-06.JPG
The old yellow wire is actually on the output side and it ties into the volume control. Perhaps for feedback ? I'm not sure about using an xfrmr without that tap.
Maybe a divider with two resistors could be used
