ViviCam 5385 LCD screen very dark?

ViviCam 5385
Switching the camera on it performs all usual opening sequences. The LCD screen remains very very dark and images are difficult to see in various lighting situations. The pictures taken are good.
The menus for settings can be dimly seen abd the setting for the LCD screen brightness is plus 5, the highest.
Is there another setting somewhere that can brighten the images on the screen?
Thanking you in anticipation