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The IF is the intermediate frequency section of the receiver, whereby the carrier signals sent out by the transmitting station (or other analog RF source) are demodulated, mixed, and converted into baseband signals which the rest of the TV's circuitry can work with. For instance, an NTSC signal is 6MHz wide, per VHF or UHF channel. In that allocated bandwidth lies the color subcarrier which is extracted from the station carrier, along with the sync pulses, sound, and actual video information.
What I was suggesting in my earlier post is to attempt an alignment of the Sound IF section, which sometimes contains adjustable coil for the trap or an additional discriminator coil.
To perform this procedure, you typically require some test gear, consisting of an sweep/marker-generator, a suitable oscilloscope (dual-trace is preferred), and the original documentation specific to your set. It really does help, IMO, to have the original documents, since they often outline the exact curves you are seeking to replicate, and a bunch of other test data.
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