Green shadows surrounding bright whites

Last point first.....contrast max default is normal.....
Next, I would adjust green screen and green focus = see if they
are working normally,if not then G2 / Focus block may be bad...
after that, I would suspect green CRT.........................T.

Finally a consumer that gives us plenty of info :)
sounds like an overdriven green tube, the only thing you can try is to find the G2/Focus block assembly, either behind front speaker grill or remove back of set and look for a black box approximately 5"X5" , this box will have 6 philips type adjustment screws(plastic) 3 are for focus, do NOT adjust these,
the other 3 are marked "screen" the center screen adjustment screw is for green, turn it VERY slowly counterclockwise while the set is running and pray that your problem dis-appears, be advised that this is a HIGH VOLTAGE device so one hand in your back pocket the other hand turns the screwdriver, if the problem does not go away you have a poor green tube, good luck, sorry I can`t give you the exact location of the G2/Focus block, manufacturers move them to different places every year.