Bally Gamemagic Monitor

[vette6048]

I have a Bally Gamemagic Tatung monitor. After 20 minutes or so the picture gets blurry. The monitor again is a Tatung E832-88 Rev B. Somewhere on the back should be a knob to adjust the picture. I do not want to start turning any knobs and cause any more problems. Anybody have any idea where this knob would be. Any help greatly appreciated!!

[montech]

Hello
See attached picture. The black transformer is the Flyback transformer. It has a 20KV output on the red wire to the CRT. The reason they named the transformer this is because if you touch it...you will  fly back!    No it actually has to do with retrace during Horz sweep times, but these will give you a NASTY shock.The top control of the two controls on the flyback is the focus control. Wait till your monitor warms up, turn off the game and pull the monitor out. Adjust the focus control slightly counterclockwise and reinstall monitor. Repeat this until you get the picture you want. I probably could use a recap job too.
Good Luck and be careful.

[cowboygames]

I wouldn't mess with that control till you find the cause of the problem. If it's running fine for 20 minutes before the focus goes to crap you probably have a capacitor going bad. The screen and focus controls control knob settings don't change with temperature. Something else has to be behind it. I've seen carbon shorts on the guns that didn't present themselves until after the tube warmed up and that is a possibility also