V-control broken on old (CRT) TV-Set?
What makes me curious is the 50 Hz noise whenever the picture is bright. Tow possible reasons come to mind:

1) Interference from the (broken?) vertical deflection stage or backwards from there to the power supply and then on to the audio amp

2) Ripple from the power supply (should be 100 Hz, though.) The total power increases for bright pictures, hence the ripple voltag would increase as well.

Does the TV have a traditional power supply that uses a 50 Hz transformer or does it have a switch-mode power supply?

Do you have a scope? Are you able to probe the various supply rails, especially the one that powers the vertical deflection circuit?

Here's an extremely good app'note with tons of typical oscillograms and ICs that are likely very similar to the ones your TV uses: http://www.nxp.com/documents/application_note/APPCHP4.pdf

...

Some more hints after I have checked my old funny book that has pages after pages with pictures of ill TVs and list their possible causes (ISBN 978-3772350580); parts refer to Fig 4 in the TDA3653 data sheet:


Check electrolytic cap in the vertical amp's supply (220 µF). Also check the decouplig resistor (4,7 Ohm)
Check electrolytic cap in the vertical oscillator or flyback circuit (100 µF).
Check big cap at deflection coil (1500 µF) and 1,2 Ohm resistor.
Check feedback circuit (4,7 µF)