Buzz in sound from video - a porthole

[zeno]

Be sure you are not turning up the AGC too much to
make up for a problem causing weak video.
With no signal you should get a nice clean snow ( dots of snow
no streaking etc) with very good contrast & a nice waterfall
sound. Anything in the tuner, IF, video, CRT & AGC can
give weak video. Start by subbing KNOWN good tubes,
dont trust a checker.......

73 Zeno