Sega Nascar Arcade - Wells Gardner 9300 series monitor issue

[Irish2010]

I have a Sega Nascar Arcade with Wells Gardner 9300 series monitor.  Everything works great.  When I got it I noticed the the screen was rolling top to bottom.  After a while it stopped.  Then I noticed that the monitor was blinking on and off every so often.  Then one time it blink off and showed "No Signal" then came right back on.  I played around with it looking for loose wires.  No I have a issue with the H Size.  The screen is only about 1.5" wide and it is still rolling top to bottom.  I can't get it to adjust to the full screen.  Thhis is a 29" monitor that has the control bottons instead of the nobs you can turn.  It is a push button control.  With the screen being so skiney I can read it to see what the on screen menu is showing to adjust the H size.  Any sugestions on how to fix this?   

[Irish2010]

Here is a picture of what the screen looks like.

[grantspain]

check for a bad solder joint

[Irish2010]

is there a certain spot to look for this?

[grantspain]

check around flyback transformer,yoke connectors,horizontal deflection circuit -it could be almost  anywhere on the chassis
a quick check to make is to bang the side of cab to see if it affects the screen