4. CASE STUDY
In many cases, a color deviation will be corrected by return- ing the HIT and WID data for the main deflection side to the initial values.
Followings are cases which need readjustment of the conver- gence by all means.
4-1. When CRT is Replaced.
When the CRT is replaced, readjustment of the main deflec- tion and color matching will be necessary. Perform the ad- justments as follows.
(1)Replace two CRTs, blue and red.
(2)Perform horizontal adjustments for blue and red yokes to the green CRT. Mount the yokes and velocity modu- lation coils + alignments so that they closely touches the CRT without any clearance.
(3)Adjust the red and blue alignments. (refer to item De- tailed adjustments for alignments)
(4)Perform the center adjustment for the blue CRT center and the red CRT center to the green CRT center with the centering magnets.
(5)Adjust the HIT, WID data to obtain the data which gives the most precision to the green.
(6)Perform the color matching in terms of the convergence for each screen. In this case, do not move the green.
(7)After completion of the convergence adjustment for each screen, replace the green CRT. For the green CRT, repeat the steps
4-2. When Convergence Unit is Replaced
When replacing the convergence units, all screens must be adjusted basically. However, performing the adjustment as shown below will reduce the procedures considerably.
(1)Replace the memory (Q713) for the new unit with the memory (Q713) for the failure unit. Mount the con- vergence unit on the set and the screen status before replacement will be directly reproduced.
(2)Mount the new unit with the old memory installed in combination on the set, and turn on the set. A screen as if it is moving vertically or horizontally will appear.
(3)Adjust each center of green, red, and blue with the cen- tering magnets again.
(4)Check to see color deviation and screen size deviation among the colors. If deviated, perform the adjustment for the main deflection and the color matching for the convergence.
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