Sorry - but you're obviously not a TV engineer, and specifically not a Sony one
The problem (on a Sony like this one) is that the scan coils have slid back along the neck of the tube, altering the purity settings - it's a VERY. VERY. VERY common fault (or it was, when CRT's were still in use!).
The answer is to loosen the clamp that holds then in place and push them back forwards, set the purity back up, and re-tighten the clamp.
It can be quite fiddly to realign it, and prone to shocks whilst doing it!.
I hated the Triny tubes, I always got the re-gunned ones to set up again, scan yoke sensitive, permalloy magnets stuck here and there to get corner convergence etc. I hated em with a passion...give me an old Philips G5 any day
My Sony Trinitron 32" TV had some of its convergence magnets laying on the bottom of the cabinet. They were held on the CRT with double-sided foam tape that does not hold when the TV gets to its normal fairly-warm operating temperature.