Compaq CRT Monitor s7500 Service Guide - Page 19

HP S7500/MV7500/CV7500 3. Rotate the individualrings of 4-pole convergence magnetsby changing the spacing between the 2 tabs to converge the vertical red and blue lines at the center of the screen. 4. Rotate the pair of rings of 4-pole convergence magnets by maintaining spacing between the 2 tabs to converge the horizontal red and blue lines at the center of the screen. 5. Rotate the individualrings of 6-pole convergence magnetsby changing the spacing between the 2 tabs to converge the vertical red, blue and green lines. 6. Rotate the pair of rings of 6-pole convergence magnets by maintaining spacing between the 2 tabs to converge thehorizontal red, blue andgreen lines. 7. Repeat the steps from 3~6 until the best convergence is obtained. Figure4-2. 4-pole and 6-poleMagnets Movement Blue Red Red/ Blue Green Blue Red Red/ Blue Green 4-pole magnets movement 6-pole magnets movement Note : The 4-pole magnetsand the 6-pole magnets interact, makingdot movement complex. 4-2-5 Degaussing Degaussing is required when poor color impurity appears on the screen. This monitor uses an automatic degaussing circuit that is activated when the power is on. The automatic degaussing will be fully functional again after the monitor has been in operation for 20 minutes. The degaussing effect is confined to the picture tube since the coils are mounted at the back of the tube. Should any part of the chassis or cabinet becomes magnetized, it is necessary to degauss the affected area witha manual degaussing coil. 4-2-6 ManualDegaussing 1. Apply line voltage to the degaussing coil andmove it in a rotary motionover the front, sides, and top of the monitor. The coil should be kept away from therear of the monitor to avoid damaging the magnetic neck components. 2. Slowly rotate and move the coil away from the monitor to about 6 feet beyond the point where no effect on the CRT will be noticeable. For proper degaussing,it is essential that the fieldbe gradually reduced by moving thecoil slowly away from the monitor. The degaussing coil must neverbe shut off or disconnected while near the monitor, as this would introduce a strong field instead of canceling the effect of the stray fields. Page 17