Screamed display, showing normal refresh rate from 75 to 60 do not ask, how to deal with

Display there screaming, the normal image, listen carefully, but there Youting not issued, the refresh rate from 75HZ to 60HZ away screaming, and then transferred back to 75HZ, there was screaming.I would like to ask how To deal with.

It is the electronic display, a long-time 1, 10, will be the case, repair it, just in case high-frequency EMP voice, and display a lot of problems that have
direct you to change the LCD be it, no voice, no radiation, no transfer refresh rate as high as issued by the screams display, should be damaged Gao Yabao , The specific circumstances need to send maintenance check can know! Piwan is estimated at fault or high-pressure gun! To solve the problem will certainly need to replace parts.But certainly not more than the cost!!