Focus Adjustment; Purity Adjustment - Durabrand DCT2405R Service Manual

17. 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.
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The following adjustments normally are not
attempted in the field. Only when replacing the
CRT then adjust as a preparation.

18. Purity Adjustment

Purpose: To obtain pure color.
Mode Input
Symptom of Misadjustment: If Color Purity
--- Monoscope
Adjustment is incorrect, large areas of color may not
Spec. be properly displayed.
See below
1. Set the unit facing east.
2. Operate the unit for over 30 minutes before
3. Fully degauss the unit using an external
4. Loosen the screw on the Deflection Yoke Clamper
5. Loosen the Ring Lock and adjust the Purity
6. Slowly push the Deflection Yoke toward bell of
7. Tighten the clamp screw on the Deflection Yoke.
5-7
Test Point Adj. Point
Deflection Yoke
---
Purity Magnet
Tape M. EQ.
Pattern
---
Generator
Figure
GREEN RED
adjusting.
degaussing coil.
and pull the Deflection Yoke back away from the
screen. (See Fig. 6)
Magnets so that a red field is obtained at the
center of the screen. Tighten Ring Lock. (See Fig.
5,6)
CRT and set it where a uniform red field is
obtained.
Mode Input
--- Red Color
Spec.
See below
BLUE
Fig. 5
L3401EA