Red does look a little over-saturated, blue too You may need to look how to adjust convergence on your set. How to do this varies between sets so check around. If you do decide to open your CRT, always exercise caution as it contains very high voltage components that keep their charge even after the set has been powered off.
You’re not saying which Trinitron model, but anyways, try to find the “HWD RED”, “HWD GREEN”, “HWD BLUE” options; they’re usually together with geometry options, though I’m not sure on NTSC models. Lower the RED value a bit and check it out. Over-driven colors (together with the focus) will normally need adjustments only possible by opening up the set, but you may alleviate a bit the problem with the service menu options.