Are you sure it is Horiz collapse and not Vertical??? Usually (but not always) when you have a Horiz fault you will lose EHT to the tube and so you will not actually see any picture at all.
Horiz and vert are determined by the way you would lokk at a NORMAL TV set - not a vertically mounted tube in an arcade machine.
So if you have a vertically mounted tube and you have a line up and down the screen, that is actually Vertical collapse and is much simpler to sort out.