Focus; White Balance - Sony TRINITRON KV-21FX20A Service Manual

(3) Screen corner convergence.
• If you are unable to adjust the corner convergence properly,
correct them with the use of permalloy assemblies.
a
a-d: screen-corner
convergence defect
c
Install the permalloy assembly
for the area that needs correcting.
b
Permalloy Assy
d
b
d
a
c

Focus

Screen
19
3-3. FOCUS
1. Receive a television broadcast signal.
2. Normalise the picture setting.
3. Adjust the focus control on the flyback transformer for the
best focus at the centre of the screen.
Bring only the centre area of the screen into focus, the magenta
ring appears on the screen. In this case, adjust the focus to
optimize the screen uniformly.

3-4. WHITE BALANCE

G2 Screen Adjustment
1. Switch the TV set into AV mode [apply a cross-hatch signal].
2. Enter into the 'Service mode' and select 'Picture Control'.
3. Enter 'Picture Control' and select 'Personal' press OK.
4. Return to 'Picture Control' menu and select 'Reset'.
5. Measure the voltages on the 3 cathodes of the CRT, Kr,Kg
and Kb using an oscilloscope with a 100:1 probe.
6. Connect the oscilloscope to the CRT cathode which recorded
the highest voltage and adjust [RV702 SCREEN] located on
the C Board to obtain a reading of 175V.
White Balance Adjustment
Note: Before carrying out the following adjustment perform the Sub
Contrast adjustment indicated in Section 4 [Circuit
Adjustments]
1. Input an all white signal from the pattern generator.
2. Enter into the Service Mode.
3. Enter into the 'Picture Adjustment' service menu.
4. Select the 'Green drive' and adjust so that the white balance
becomes optimum.
5. Select the 'Blue drive' and adjust so that the white balance
becomes optimum.
6. Press the 'TV' button on the remote commander to return to
TV operation.