What most likely happened here is that that the solder connections to the degaussing thermistor went bad and opened up on the initial surge after turnon.

The idea is to magnetise one way and the other at less and less strength, evenually decaying to zero. What hapens in this failure mode is it gets magnetised one way, the connection breaks and the process is incomplete.

Because of the high amperage involved there is usually a brown ring around the connection. To resolder you have to remove the old solder and clean the pin as well as the pad.

The other possibility is the shadow mask (aperature grill in a Sony) cut loose. There is no fix for that, though I can do wonders with magnets around the bell of the CRT. The problem with that is that it might not be stable.