Case study – Toshiba TW40F80 User Manual

Page 96

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 2-5 to make the color matching in terms

of the convergence by using the red and blue as the

reference.

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.