You can switch off the backlight (illumination) of the LCD screen of the E5052B. This extends the life of the backlight when using it continuously over a long period.
Press System key.
Press Backlight to switch the backlight ON/OFF.
Switching off the backlight causes indications on the LCD screen to be almost invisible.
The backlight that has been switched off can be turned on again by pressing Preset. When the LCD backlight is off, Preset works as a key for switching the backlight back on.