Samsung LS27E591CS/XV, LS27E591CS/EN, LS27E591CS/CI Screen issue, Not Optimum Mode is displayed

8Troubleshooting Guide

Screen issue

Issues	Solutions
The power LED is off. The screen will not switch	Check that the power cable is connected
on.	properly. (Refer to "2.2 Connecting and Using a
	PC")
The message Check Signal Cable appears.	Check that the cable is properly connected to the
	product. (Refer to "2.2 Connecting and Using a
	PC")
	Check that the device connected to the product is
	powered on.
Not Optimum Mode is displayed.	This message appears when the signal from the
	graphics card exceeds the maximum resolution or
	frequency for the product.
	Change the maximum resolution and frequency to
	suit the product performance, referring to
	Standard Signal Mode Table (page 86).
The images on the screen look distorted.	Check the cable connection to the product (Refer
	to "2.2 Connecting and Using a PC")
The screen is not clear. The screen is blurry.	Adjust Coarse (page 53) and Fine (page 54).
	Remove any accessories (video extension cable,
	etc.) and try again.
	Set the resolution and frequency to the
	recommended level.
The screen appears unstable and shaky.	Check that the resolution and frequency for the
	PC are within the range of resolution and
There are shadows or ghost images left on the
	frequency compatible with the product. Next, if
screen.
	required, change the settings, referring to
	Standard Signal Mode Table (page 86) in this
	manual and the Information menu on the
	product.
The screen is too bright. The screen is too dark.	Adjust Brightness (page 37) and Contrast (page
	38).
Screen color is inconsistent.	Change the Color settings. (Refer to "3.5 Color")
The colors on the screen have a shadow and are	Change the Color settings.
distorted.	(Refer to "3.5 Color")
White does not really look white.	Change the Color settings.
	(Refer to "3.5 Color")

8 Troubleshooting Guide 79