Neo geo two slot, looks to be a conversion cab from a previous machine. Im able to adjust colors etc fine, but when things on the screen are bright, the screen brightness becomes seems to raise, but as soon as most of the colors on the screen are dark, the monitor seems to automatically adjust brightness down. I also get retrace lines when the screen goes very bright. I'm very new to this, but am pretty familiar with any terms mentioned relating to this, but don't have a whole lot of knowledge on the subject. Anyone care to help? Anything thoughts are appreciated.

G2 screen is turned all the way down on the flyback, and brightness can be adjusted via the pot obviously, but the brightness does not change if the image is fairly still.

Also, the monitor is a pentranic A63PNT13X. The chassis doesn't seem to have a model number of any sort on it.

Here is a video trying to show the brightness issue.