Nanao MS8-26 monitor brightness issue

[Tealsnk]

I have an arcade monitor, it's Nanao MS8-26 in a Sega Aero City. It flickers from regular brightness to less bright (dim). Almost like it flickers and dims, then flickers and gets brighter again. You can see what I'm referring to very clearly early in the video attached. Any idea as to what's causing it.
I did notice that when I smacked the side of the machine, it flickered back to it's normal brightness again temporarily.
Link to video below. Thanks!
http://imgur.com/a/WIUsblo

 

[nem]

A cold solder joint and / or dirty pots.

 

[Asobu]

Yeah check every solder point on your monitor chassis.

But moreover, what's going on with those character select sprites? They look so blurry