akira CT-21XF9, Service Manual

Page: 13 / 77

13
Model No: CT-21XF9A
Version 1.0
FOCUS ADJUSTMENT
1. Use the remote control to set the contrast to maximum and the brightness, chroma to medium.
2. Set H. V. lines near Philips picture center to thinnest with the focus adjustment potentiometer
on the FBT. After finishing adjustment, ensure that no poor focusing exist near the center or
around of the frame.
Before Adjusting After adjusting
SET-UP ADJUSTMENT
The following adjustments should be made when a complete realignment is required or a new picture
tribe is installed. Perform the adjustments in order as follows:
1. Colour purity
2. Convergence
3. White Balance (See page 17)
Note: The PURITY/CONVERGENCE MAGNET assembly and rubber wedges need mechanical
positioning. Refer to figure 6.
COLOUR PURITY ADJUSTMENT
NOTE: Before attempting any purity adjustment, the receiver should be operated for at least
fifteen minutes.
1. Demagnetize the picture tube and cabinet using a degaussing coil.
2. Set the brightness and contrast to maximum
3. Receive the green raster test signal.
4. Loosen the clamp screw holding the deflection coil and slide, the backward or forward to
provide vertical green belt (zone) in the picture screen.
5. Remove the Rubber Wedges.
6. Rotate and spread the tabs of the purity magnet (See figure 7) around the neck of the picture
tube until the green belt is in the centre of the screen.
7. Slowly move the deflection coil forward or backward until a uniform green screen is obtained.
Tighten the Clamp screw of the coil temporarily.
8. Check the purity of the red and blue raster.