wrote in message
...
i am trying to repair a video slot machine. the monitor image is not
correct. the image is shifted to the left and cut off. there is a black
vertical bar, about 15% of the screen size in the right 3/4 of the screen
. to the right of that is the beginning of the image that is shifted to
the left. i took the monitor to a repair shop, and he says the
monitor/chassis is ok. i'm not too sure about that. a different mpu in the
slot has the same result. its a tatung VT-1440S monitor, VGA . i would
like to hook up a desktop vga monitor.

i posted an image from the slot schematics he
http://s408.photobucket.com/user/mho...GA%20interface

It sounds like a phasing problem - its a simple fault to fix, but not simple
to find the part.

Usually; the phase is sampled from a winding on the horizontal transformer.
There's usually a high resistor in series with that signal on its way to the
horizontal oscillator. If that's in a chip - its usually easy to trace the
path to the transformer.

Another possibility is the scan energy recovery system, the left to centre
part of the scan is driven by recovered energy - the horizontal transistor
drives from centre to RHS, the energy is recovered at the end of that. A
fault there usually causes cramping (horizontal linearity) but early onset
faults can distort the waveform back to the phase discriminator.