Magnavox 19MDTR20 Service Manual page 18

12. Head Switching Position Adjustment
Purpose: Determine the Head Switching Point during
Playback.
Symptom of Misadjustment: May cause Head
Switching Noise or Vertical Jitter in the picture.
Note: Unit reads Head Switching Position automati-
cally and displays it on the screen (Upper Left Corner).
1. Playback test tape (VFMS0001H6).
2. Enter the Service mode. (See page 1-4-1.)
Then press the "5" button on the service remote
control unit.
3. The Head Switching position will display on the
screen; if adjustment is necessary follow step 4.
6.5H(412.7µs) is preferable.
4. Press "CH o" or "CH p" button on the service
remote control unit if necessary. The value will be
changed in 0.5H steps up or down. Adjustable
range is up to 9.5H. If the value is beyond adjust-
able range, the display will change as:
Lower out of range: 0.0H
Upper out of range: -.-H
5. Turn the power off and on 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.
13. 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.
Adj. Point
Deflection Yoke Purity Magnet
M. EQ.
Pattern Generator
GREEN
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. 6.)
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. 5,6.)
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.
1-4-5
Input
Red Color
Spec.
See below.
Figure
RED
BLUE
Fig. 5
TD857EA