In my experience those were the best type, but fairly rare (we only had one like that, and were unable to source any more) - most you could buy were rod shaped, a bit like a small rolling pin. I would have thought the chnaces of finding them now is pretty remote, as CRT is long obsolete.they used to make handheld degaussing coils to eliminate residual magnetism on the shadow mask and internal steel parts on the TV... they are about 18" diameter hoops with a power cord and switch and many turns of wire make up the hoop.
Not much point setting up the purity facing north or south, and then moving it to where you wantiirc, there were some TVs an computer monitors where you were supposed to do the degaussing and purity adjustment with the crt facing north or south to minimize the effects of the earth's magnetic field. gegaussing hoops were common in the USA, the only rod shaped ones i ever saw were small ones made for tape head degaussing. i suppose one of those could be used for a crt in a pinch, but they only cover a small area at a time
As I recall we used to keep three different (and incompatible) types, two were three pin, and the later one was only two pin. Those three fitted pretty all TV's.the degaussing coil of the crt is driven on startup by a component that was commonly called a degaussing 'posistor'; if you google it for that make of tv you may still find it as a spare part - otherwise if you can salvage one from another tv of the same make there's a good chance it will be an identical component.
That sounds a HIGHLY unlikely occurrence?, and Trintron tubes don't even have a shadow mask (which I presume you mean by 'hole mask'?), they have an array of vertical wires instead, supported by a small number (two or three) horizontal wires.When degaussing has no effect, the hole mask inside the CRT could be out of position.
Then the CRT is'nt reperable, because You can't open it.
I had this once long time ago at a Sony TV.
I guess the tube has got a mechanical shock in this case to get this failure.
I suggest your book is a load of crapI've take a look into my TV screen error Book.
1. Degaussing unit failure. Degaussing Coil out of position ( That was testet here ? )
2. Faulty Mask by massive mechanical shock
Fact is the Electronic Ray doesn't fit to the luminiscent pixels at some positions of the screen.
Tanmay could show a grid or a test picture on the screen to see other faults too ( E/W or N/S correction ).