Brightness issue Nanao Ms8-26U

[Tadao]

Hi, i have a brigthness issue in my Nanao Ms8-26u.   I reflowed the chassis, neckboard, replace the brightness knob and recaped the entire chassis, but the problem remains.  Shaking the cables don't make any difference. The problem is the same with a jamma pcb or mister fpga via J-pac and is very random, sometimes have the issue and sometimes works perfect.  żAny suggestion?

This is a video of the issue



Regards