[old_tv_nut]

If you have a video playing through the tuner (not still mode, so the audio is not muted) you should see the 4.5 MHz interference dancing around with the audio, and may be able to tune the trap precisely for minimum interference. If the trap is tuned a bit too low, resetting it may reduce your color ringing (but of course, if the previous idiot fiddled with everything, other mistunings may be contributing the color ringing).