Phil Allison wrote:
"Tim Worthington"

I'm thinking about putting a posister, the coil and a degauss
button
in series with the 240v mains available inside the box.


** You need a bit more than that - usually a hefty relay is used to
engage
the posistor circuit with a timer to hold it on for 5 seconds or so.
The
button just initiates the timing cycle.

I have Sanyo TVs built over 20 years ago that use nothing but a
posistor in series with the degaussing coil.