The Amateur TV Repair
The CRT And The Scope Screen
Examining the vertical deflection waveform with the scope showed the problem being a parasitic high frequency oscillation around the vertical output IC. The X-Ray radiation in a TV set is emitted from the effect of the High Voltage drive generating the electron beam. The density of the holes in the shadow mask set an upper limit on the resolution supported by that monitor.
The Cause Of A Missing Power Supply Voltage
In the picture above the push button is on the other side of the board along with the LEDs. The connection to the CRT is usually a separate wire running from the flyback or its neighborhood to the CRT neck board. The higher the number the more sensitive to light, in that the less light is needed to take a well exposed photo.