Colored halo appears around image due to color guns out of alignment.
Cause:
The color guns located in the display unit, which shoot the colors red, green, and blue light at the screen are misaligned. Moving the display around or old age can cause this.
Solution:
Adjust the color controls on the monitor using the external convergence controls.
NOTE: If 'halos' begin to appear constantly around images, you may need to replace the display unit or have it repaired by a qualified computer technician.
1) Locate the convergence controls on the display unit.
NOTE: For the exact location of the controls, consult the manual that came with the display unit.
2) Adjust each knob until the right balance of colors appears on the display image.
