Toshiba 3787DB - Set-Up Adjustment; Color Purity Adjustment

WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”, “SAFETY PRECAU-
TION” AND “PRODUCT SAFETY NOTICE” ON PAGE 3 OF THIS MANUAL.
SET-UP ADJUSTMENT
Bi The following adjustments should be made when a complete realignment is required or a new picture tube is installed.
Perform the adjustments in order as follows :
1. Color Purity
2. Convergence
3. White Balance
Note: The PURITY/CONVERGENCE MAGNET assembly and rubber wedges need mechanical positioning.
Refer to figure 1.
”
pad
=
Lud
=
=
2]
pan)
pr)
Q
<t
wl
<<
oc
Lu
2
Lud
1]
* There are no adjustment of purity and convergence in some picture tube (Unified with purity magnet).
COLOR PURITY ADJUSTMENT
NOTE : Before attempting any purity adjustments, the receiver 5. Remove the Rubber Wedges.
should be operated for at least fifteen minutes. 6. Rotate and spread the tabs of the purity magnet (See fig-
1. Demagnetize the picture tube and cabinet using a degauss- ure 2.) around the neck of the picture tube until the green
ing coil. belt is in the center of the screen. At the same time, enter
2. Set the brightness and contrast to maximum. the raster vertically.
3. Use a green raster from among the built-in test signals. 7. Slowly move the yoke forward or backward until a uniform
4. Loosen the clamp screw holding the yoke and slide the green screen is obtained. Tighten the clamp screw of the
yoke backward or forward to provide vertical green belt yoke temporarily.
(zone) in the picture screen. 8. Check the purity of the red and blue raster.
TEMPORARY
DEFLECTION MOUNTING
YOKE
29.1mm(28", 29") |
25mm(25")
19mm(19", 20", 21") ae
14mm(13", 14") Int
~ oe RUBBER WEDGE
ADHESIVE
PURITY/
CONVERGENCE
DEFLECTION
MAGNET
ASS'Y
r
YOKE
GLASS CLOTH
TAPES
Figure 1.