Emerson 6420FE service manual Sub-Brightness Adjustment, Focus Adjustment, Purity Adjustment

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	Mode		Input
---		CH o / p	RF		IQW
		buttons
	Tape	M. EQ.		Spec.
---		Pattern	See below
		Generator
		Figure

White	Black
	This bar
	just
	visible
	Fig. 4

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	Mode	Input
---	Focus Control	---	Mono-
			scope

Tape	M. EQ.	Spec.
---	Pattern	See below
	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.

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	Mode		Input
	Deflection			Red
---	Yoke Purity	---
				Color
	Magnet
Tape	M. EQ.		Spec.
---	Pattern	See below.
	Generator
	Figure

GREEN RED BLUE

Fig. 5

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.

5-6 L2401EA