It's likely to be just a dry joint to the co-ax socket centre pin inside the tuner. As a result of mechanical stress, you often get hairline fracture to the printed circuit at the point the socket centre pin connects to board, particularly if you've had to apply pressure over a long period or manipulate the socket to obtain a picture. Also common are dry joints to the chassis connection inside tuner and coils inside I.F. module. If resoldering is unsuccessful then the Tuner & I.F. are expensive parts to replace and probably not worth replacing on an old TV.
Cobweb
September 2004