Got this Philips 14" B&W tv ages ago.
Symptom : Video muted with no sound.
So where would one start? I was thinking maybe tuner section or IF.
Turned out the speaker was shorted, the volume was set to high, hence
supplies were dropping due to an unnatural load. Disconnected speaker
wire and voila, picture was restored. Recoiled the speaker and
everything worked fine.
Jango.