sounds like CRT. Try this.
In totally dark room turn down( off) color level.
Turn down brite & contrast most the way but still has pix.
Is it a good B&W pix or a color?
Now turn up the brite & contrast does the pix get worse ?
Does the color of the pix change ? Focus go bad ?
Are streaks shooting to the right of brite areas ?
Bottom line is a set with a weak jug can look normal when you
dont drive it hard. If you put up some screen shots may be able to
tell for sure. In person 99.9% I can make the call fast.
Sorry to hear about your mother. Lost mine last fall & it sure
changes things. But she was 97 and happy with the time she had
& ready for the next step. Now we talk of her & smile remembering her
& all she did for us.
73 & GB Zeno