For the buzz try the AGC adj & buzz control. Next change the
detector tube. If still buzzes you can adj the detector AKA
quad coil. Dont go more than 1/2 turn & flag your stick so you
can go back where it was. If no joy check around the det.
Never had a component failure so no help there. A few sets went
out with just a light buzz on heavily white scenes. Newer content
& lack of OTA make make this a bit of a compromise.
73 Zeno
LFOD !