Convergence Adjustment; Purity Adjustment - Emerson CR202EM8 Service Manual

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.

17. Purity Adjustment

Purpose: To obtain pure color.
Symptom of Misadjustment: If Color Purity
Adjustment 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
1. Set the unit facing east.
2. Operate the unit for over 30 minutes before
adjusting.
3. Fully degauss the unit using an external
degaussing coil.
4. Loosen the screw on the Deflection Yoke Clamper
and pull the Deflection Yoke back away from the
screen. (See Fig. 7)
5. Loosen the Ring Lock and adjust the Purity
Magnets so that a red field is obtained at the
center of the screen. Tighten Ring Lock. (See Fig.
6,7)
6. Slowly push the Deflection Yoke toward the bell of
CRT and set it where a uniform red field is
obtained.
7. Tighten the clamp screw on the Deflection Yoke.
Mode Input
--- Red Color
Spec.
See below
RED BLUE
Fig. 6

18. Convergence Adjustment

Purpose: To obtain proper convergence of red, green
and blue beams.
Symptom of Misadjustment: If Convergence
Adjustment is incorrect, the edge of white letters may
have color edges.
Test Point Adj. Point
C.P. Magnet (RB)
--- C.P. Magnet (RB-G)
Deflection Yoke
Tape M. EQ.
--- Pattern Generator
CRT
DY WEDGE
DEFLECTION YOKE
C.P. MAGNET (RB)
R
G
B
C.B. MAGNET (RB-G)
RB
G
1. Loosen the Ring Lock and align red with blue dots
or Crosshatch at the center of the screen by
rotating (RB) C.P. Magnets. (See Fig. 8)
2. Align red / blue with green dots at the center of the
screen by rotating (RB-G) C.P. Magnet. (See Fig.
9)
3. Paintlock the C.P. Magnets after adjustment.
5-7
Mode Input
Dot Pattern
--- or
Crosshatch
Spec.
See below
Figure
PURITY RB RB-G
COIL
SCREW
RING LOCK
SCREW
C.P. MAGNET CLAMPER
C.P. MAGNET
COIL CLAMPER
Fig. 7
R
G
B
Fig. 8
RB
Fig. 9
P7150EA
G