TV humming sound

If you mute or turn down the volume, does the hum go away?  If it does, there is a capacitor inside the set, in the power supply that feeds b+ to the audio IC, and most likly to other locations inside the set.  The correct way to fix this set is to get a service schematic, locate the said power supply feed, and start replaceing capacitors, unless, you have an ESR meter to check the capacitors in the circuit.  If you have no TV repair experience, please seek out the assistance of a trained tech as this set has alot of high voltage inside them, and there are no real user replaceable parts inside these sets.  Please keep us informed on the repair of this set and Good Luck

Ok then you have a "singing" coil or transformer.  The only thing I can recommend is if you know your way around a TV circuit, and know the saefty rules for serviceing TV sets, open the back, turn on the set, and see if you can localize where the humming is comming from.  It could be the deflection yolk on the back of the picture tube around the neck, or the high voltage trasformer, or a smaller coil or transformer somewhere on the board.  These can be dificult to locate.  If you can hear where its comming from, lite pressure with a wooden dowl or wooden spoon may changre the tone so you can be sure what to replace.  Now sometimes, there is a noise comming from the sweep and main power supply because of a capacitor going bad.  A test of the power supply waveforms on an ocilliscope will verify that.  Like I said, if you have no TV serviceing experience, please play it safe and call in a pro to assist you with this repair.  Good Luck and keep us posted on the repair progress.

If it is a bad capacitor thats causing the noise, the set will simply get another  fault symptom.  If it is a coil or transformer causing it, Nothing will happen except it could get louder.