Purity Adjustment - Sylvania CD202SL8 Service Manual

11. Cut-off Adjustment
Purpose: To adjust the beam current of R, G, B, and
screen voltage.
Symptom of Misadjustment: White color may be
reddish, greenish or bluish.
Test Point Adj. Point
Screen VR
--- [CH. o / p]]
buttons
Tape M. EQ.
Pattern
---
Generator
Figure
PATTERN GENERATOR
RF INPUT
Note: Screen VR FBT --- Main CBA
FBT= Fly Back Transformer
Use the service remote control unit
1. Degauss the CRT and allow the unit to operate for
20 minutes before starting the alignment.
2. Input the Black Raster Signal from RF Input.
3. Enter the Service mode in TV/VIDEO mode.
4. Press [VOL n] button on the service remote
control to enter "C/D" mode. (Display changes "C/
D," "YUV MEMORY," "TUNER," "QAM," "DTV-H,"
"D-SOUND," "DL V-CHIP," and "RC5" cyclically
when [VOL n] button is pressed.)
5. Press [1] button on the service remote control unit
and select "COR" mode.The display will
momentarily show "COR". Now there should be a
horizontal line across the center of the picture tube.
If needed, gradually turn the screen control on the
flyback clockwise until the horizontal line appears.
Adjust the Red Cut off by pressing the "[CH. o /
p]" buttons. Proceed to Step 6 when the Red Cut
off adjustment is done.
6. Press [2] button on the service remote control unit
and select "COG" mode. The display will
momentarily show "COG". Adjust the Green Cut off
by pressing the "[CH. o / p]" buttons. Proceed to
step 7 when the Green Cut off adjustment is done.
Mode Input
Black Ras-
RF
ter
Spec.
See Reference
Notes below.
Fig. 5
6-6
7. Press [3] button on the service remote control unit
and select "COB" mode. The display will
momentarily show "COB". Adjust the Blue cut off
by pressing the "[CH. o / p]" buttons. When done
with steps 5, 6 and 7 the horizontal line should be
pure white. If not, then attempt the Cut off
adjustment again.
The following 2 adjustments normally are not
attempted in the field. They should be done
only when replacing the CRT then adjust as a
preparation.

12. Purity Adjustment

Purpose: To obtain pure color.
Symptom of Misadjustment: If Color Purity Adjust-
ment is incorrect, large areas of color may not be prop-
erly displayed.
Test point Adj. Point
Deflection Yoke
---
Purity Magnet
Tape M. EQ.
--- Pattern Generator
Figure
GREEN
* This becomes RED COLOR if the [7] button is
pressed while in service mode.
1. Set the unit facing east.
2. Operate the unit for over 30 minutes before adjust-
ing.
3. Fully degauss the unit using an external degauss-
ing coil.
4. Set the unit to the AUX mode which is located
before CH2, then input a red raster from video in.
5. Loosen the screw on the Deflection Yoke Clamper
and pull the Deflection Yoke back away from the
screen. (See Fig. 7.)
6. Loosen the Ring Lock and adjust the Purity Mag-
nets so that a red field is obtained at the center of
the screen. Tighten Ring Lock. (See Fig. 6,7.)
7. Slowly push the Deflection Yoke toward the bell of
the CRT and set it where a uniform red field is
obtained.
8. Tighten the clamp screw on the Deflection Yoke.
Mode Input
--- *Red Color
Spec.
See below.
RED
BLUE
Fig. 6
P7450EA