Abstract: A vertical compensation circuit for a digital TV receiver having a vertical drive signal that is insensitive to changes in CRT beam current includes a variable gain amplifier and means for sensing changes in B+ operating potential that track changes in CRT high voltage which is related to CRT beam current. The voltage sensing means detects a change in B+ operating potential and applies a voltage indicative of that change to a feedback circuit for changing the feedback level on a variable gain amplifier to which the vertical drive signal is applied.

Abstract: A system for preventing CRT phosphor burn in a multiple CRT projection type television system is disclosed. The absence of an electron beam deflection signal in the deflection yoke of a CRT is detected and used to provide a signal to CRT shutdown circuitry by means of an unbalanced transformer approach in which the various deflection yoke signals energize a plurality of primary transformer coils with a shutdown signal provided by the transformer secondary when a primary coil flux unbalance occurs.