Quote:
Originally Posted by old_tv_nut
Yes, definitely a sign of something in the video during retrace. Does the visibility increase when you turn the brightness up? Can you see the h sync then? This would mean there's insufficient retrace blanking. (Not familiar with this schematic, so don't know what provisions there may be for blanking.)
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Yes increasing the brightness does increase the brightness of the white vertical line along with the background brightness. If I lower the brightness so the whole screen just goes dark I can still see the vertical white line as shown on a couple of previous pictures. I could not see anything else, so I guess I do not see the h sync. With the brightness all the way up I do see some slanted retrace lines (like on the 40's BW sets), but they go away just under full brightness. Here is a screen capture of the SAMs showing the vertical blanking signal on the cathode of the CRT. My scope shows the 15V pulse riding on a 142V DC level.