Peavey Classic 20W MH bias signalling and protection circuits explained

In this short video, Im trying to explain how bias circuit and output transformer protection circuits work, please excuse the mistake of K/T points reference, K point obviously does mean 'Cathode' as it would have been marked C as opposed to K, but its where cathodes are connected anyway, if you want to know how to set bias with your multimeter, please watch my previous video about it, thanks for watching.