[murphyv310]

Hi.
As Steve says you have a hum problem, hence the caps he has suggested, are you using an aurora? If so can you try it with a signal from a freeview box etc, does it stop the hum? I have this on my sets (not them all) perfect with a program but bendy on the testcard, smoothing is perfect and checked out on the scope.

Regarding the centreing try loosening the four nuts on the focus assembly that bolts onto alloy tube cradle and reposition till the space around the tube is roughly equal, retighten the nuts whle holding the focus magnets so the assembly doesnt move tighten the nuts in an X sequence just a bit at a time. This should help the centreing.
I know John has said about the scan coils, perhaps I have been unlucky but I have had the later ones fail too, I believe though any Pye with a 70 degree tube will have scan coils that will do.
good Luck