On Tuesday, July 4, 2017 at 8:44:59 PM UTC-4, wrote:
ive got a tovis mtg-1901cn cga color monitor. in use, or with a test pattern, the image starts out perfectly at the top. as you move down toward the middle , it gradually starts to compress the image, with more compression the closed you get to center. and when it gets to mid screen, its a full vertical collapse. bright while line across the center, with no image whatsoever in the lower 50% of the screen. also sold as a vision pro .

battery voltage is good at 123, 12v and 24 v are good. 123 volts at the flyback.
the vertical output ic is a LA7833. pin 6 has good 24 volt supply, and pin 2 ( output) is a nice 24 v square wave. i recapped the monitor, and the image is exactly the same. now im stuck.

thanks

I didn't read back through all the posts, but if you haven't, check the pump up diode. The anode will be connected to the Vcc and the cathode to the pump up pin of the vert IC. A weak diode here will cause all sorts of havoc (don't check it with a dmm - they often sag under load). Also, I know you said you recapped the monitor, but make sure the yoke coupling capacitor was included. This is typically a high value capacitor (around 1000uf or more).