
34 | CHAPTER 5 – TROUBLESHOOTING
To remove a
persistent image
1. Turn off the interactive display and the computer.
2. Leave the interactive display and the computer off for the same length of time as 
the persistent image was on-screen. For example, if the interactive display 
displayed an image for one hour and a residual image remains, don’t turn on the 
computer and the interactive display until after a minimum of one hour.
Troubleshooting Unstable or Unfocused ImagesComplete the following steps if your LCD screen displays an unstable or unfocused 
image.
To troubleshoot
unstable or unfocused
image issues
1. Turn off the interactive display, and then turn off the computer.
2. Disconnect the video cable that connects the interactive display’s bottom terminal 
panel to the computer.
3. Connect the video cable from the interactive display’s bottom terminal panel to the 
computer.
4. Turn on the interactive display, and then turn on the LCD monitor.
5. If the LCD monitor still dis plays an unstable or unfocused image, open the 
on-screen menu, and then change the image settings in the Adjust sub-menu. If 
this resolves the issue, you could need to change the image settings again the 
next time you change display modes.
Troubleshooting Resolution IssuesTo troubleshoot
resolution issues
Open the on-screen menu, and adjust the resolution. For more information, see 
Wireless Remote Control Buttons on page 25.
For additional troubleshooting suggestions, see the NEC MultiSync S521 User’s 
Manual (document 145185).