Just finally had my 7 year old HEB house brand tv piss me off. Black spot in middle that persists.
Replaced her today with a relatively inexpensive sharp 50 inch LED
Try demagnetizing the screen. Many color CRTs have/had demag circuits ("degaussers") in them, but not all.
That can happen when kids or experimentally-minded 70yos bring magnets to the screen to watch the colors shift when the magnet bends the electron beams. Leaves the iron-based color matrix screen with a bazillion holes in it (the "shadow mask") right behind the phosphor layer magnetized in spots and throws the beams off permaninkly at those locales.
So the electron beams hit the iron-based screen (shadow mask) and are barely able to hit the phosphors. (This generates soft x-rays, by the way.) This results in possible dark spots or spots where the colors are off --as in if the now-bent "green" electron beam hits the red phosphors.
Terry
