Another monitor question - very weird geometry distortion

[Jeff7]

This is about someone else's monitor. The picture looks like this.

Just the bottom part there is really off. I read over a monitor FAQ, and it sounds almost like an open winding in a deflection coil. Has anyone seen anything like this? Agree or disagree with my diagnosis?

 

[nineball9]

Possibly. You may have encountered an FAQ describing keystoning which is a trapezoidal pic. Your diagram doesn't really show keystoning though (think of highway signs in PA - the Keystone state.)

I'd check the pincushion circuits - bottom pincushion amplitude to be excessive. Depending on the complexity of the monitor design, there may be seperate side, top and center pincushion circuits. (Simple pincushioning problems would result in a screen bowed in at the sides - both the top and bottom would appear wider. Newer and larger monitors will more complex pincushion circuits.)

Also try checking low voltage supply as faults in this area can cause geometry problems of all sorts including ones similar to your diagram.

Could be vertical foldover, though I don't know if a modern monitor will do this (I suspect it can). what does a crosshatch screen look like?

Good luck!