Purity Adjustment; Focus Adjustment - Emerson 20" Color Television 6420FE Service Manual

14. Sub-Brightness Adjustment
Purpose: To get proper brightness.
Symptom of Misadjustment: If Sub-Brightness is
incorrect, proper brightness cannot be obtained by
adjusting the Brightness Control.
Test Point Adj. Point
CH o / p
---
buttons
Tape M. EQ.
Pattern
---
Generator
Figure
White
Note: IQW Setup level --- 7.5 IRE
Use service remote control unit
1. Enter the Service mode. (See page 5-1)
Then input IQW signal from RF Input.
2. Press "MENU" button on the service remote control
unit and Select "BRT" mode. (Display changes
"BRT," "CNT," "CLR," "S-CLR," "TNT," "V-TNT," "S-
TNT," "SHARP," and "S-SRP," cyclically when
"MENU" button is pressed). Press "CH o/p" buttons
so that the bar is just visible (See above figure).
3. Turn the power off and on again. (Main power but-
ton on the TV unit.)

15. Focus Adjustment

Purpose: Set the optimum Focus.
Symptom of Misadjustment: If Focus Adjustment is
incorrect, blurred images are shown on the display.
Test Point Adj. Point
--- Focus Control
Tape M. EQ.
Pattern
---
Generator
Note: Focus VR (FBT) - Main CBA,
FBT=Fly Back Transformer
1. Operate the unit more than 30 minutes.
2. Face the unit to the East and Degauss the CRT
using Degaussing Coil.
3. Input the Monoscope Pattern.
4. Adjust the Focus Control on the FBT to obtain
clear picture.
Mode Input
RF IQW
Spec.
See below
Black
This bar
just
visible
Fig. 4
Mode Input
Mono-
---
scope
Spec.
See below
5-6
The following adjustments normally are not
attempted in the field. Only when replacing the
CRT then adjust as a preparation.

16. Purity Adjustment

Purpose: To obtain pure color.
Symptom of Misadjustment: If Color Purity Adjust-
ment is incorrect, large areas of color may not be
properly displayed.
Test Point Adj. Point
Deflection
--- Yoke Purity
Magnet
Tape M. EQ.
Pattern
---
Generator
Figure
GREEN RED
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. Loosen the screw on the Deflection Yoke Clamper
and pull the Deflection Yoke back away from the
screen. (See Fig. 6)
5. 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. 5,6)
6. Slowly push the Deflection Yoke toward bell of
CRT and set it where a uniform red field is ob-
tained.
7. Tighten the clamp screw on the Deflection Yoke.
Mode Input
Red
---
Color
Spec.
See below.
BLUE
Fig. 5
L2401EA