Philips 24MC4306/37 Service Manual page 27

13. Head Switching Position
Adjustment
Purpose: Determine the Head Switching Position
during Playback.
Symptom of Misadjustment: May cause Head
Switching Noise or Vertical Jitter in the picture.
Note: Unit reads Head Switching Position
automatically and displays it on the screen (Upper Left
Corner).
1. Playback test tape (VFMS0001H6).
2. Enter the Service mode. (See page 1-7-1.)
Then press the number [5] button on the 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 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
adjustable range, the display will change as:
Lower out of range: 0.0H
Upper out of range: -.-H
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.
14. 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
--- Pattern Generator
GREEN
* This becomes RED COLOR if the [7] button is
pressed while in service mode.
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. 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
Magnets 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.
1-7-6
Mode
--- *Red Color
M. EQ. Spec.
See below
Figure
RED
Input
BLUE
Fig. 5
T2221EA