|
Saticons are constantly burning in the image, even of ordinary scene areas that are not overly bright. The three-saticon high def cameras used early in HDTV could not be left staring at a fixed scene without it becoming visible as a ghost image. Fortunately, if pointed at a white card/wall for a while (like 20 minutes), the burned image would gradually disappear. Your ceiling light may have overdone it and become permanent - the only way to find out is to do the white card treatment and see if it disappears.
The tiny sharply defined white spots are likely internal particles from pointing the camera down and will not be fixable.
I agree with Dave A that the black spot is likely dirt that could be cleaned off the tube face.
The green blotches are a problem of single-tube cameras, which depend on sensing the carrier frequency caused by color filter stripes on the tube faceplate. If the beam focus and/or astigmatism varies across the target, it changes the amplitude of the red and blue signals compared to the green. Usually it is just the focus (more than astigimatism), meaning that both red and blue are reduced in the poor focus areas and green predominates. If the astigmatism gets bad, it could preferentially attenuate red more than blue or vice-versa. The Quasar VK747 seems to have good spot focus in a ring half-wayout from the center (where the reds are strong), and poor focus in both the center and edges. When new, all these single tube cameras had some color imbalance near the edges, but they should not be as bad as your example. The camera needs a good adjustment of beam alignment, and also you would need to check if there is a dynamic focus voltage in this design, in which case it may not be correct due to aging of components or misadjustment.
The vertical stretch at the bottom is caused by poor vertical scan linearity. The fault in the camera is a shrinkage of the scan near the bottom, which produces the opposite effect in the image. I'd suspect a leaky capacitor somewhere in the vertical sweep circuit.
|