Sony KV-21FX250 Service Manual ▷ View online
KV-21FX250/21FX250A/21FX250C
KV-21FX250/21FX250A/21FX250C
9
1-1. REAR COVER REMOVAL
SECTION 1: DISASSEMBLY
1-2. CHASSIS ASSEMBLY REMOVAL
1 Remove screws from top of Rear Cover. 8 Screws
+BVTP 4x16 TYPE2 IT-3
2 Remove screws from top of Rear Cover. 1 Screw +BVTP
4x16 TYPE2 IT-3
Slide to remove Rear Cover from Beznet.
1 Disconnect speaker wire and H1 Board connector.
2 Remove AC cord holder from bottom cover.
3 Release wire from purse lock.
4 Release claw and slide out A Board.
Slide to move A Board
1
2
1
3
4
2
KV-21FX250/21FX250A/21FX250C
KV-21FX250/21FX250A/21FX250C
10
1-3. SERVICE POSITION
1 Release HV Cable holder.
Rotate A Board.
1
KV-21FX250/21FX250A/21FX250C
KV-21FX250/21FX250A/21FX250C
11
1-4. PICTURE TUBE REMOVAL
WARNING: BEFORE REMOVING THE ANODE CAP
High voltage remains in the CRT even after the power is disconnected. To avoid electric shock,
discharge CRT before attempting to remove the anode cap. Short between anode and CRT
coated earth ground strap.
High voltage remains in the CRT even after the power is disconnected. To avoid electric shock,
discharge CRT before attempting to remove the anode cap. Short between anode and CRT
coated earth ground strap.
ANODE CAP REMOVAL PROCEDURE
WARNING: High voltage remains in the CRT even after the power is disconnected. To avoid electric shock, discharge CRT before attempting to remove
the anode cap. Short between anode and coated earth ground strap of CRT.
NOTE: After removing the anode cap, short circuit the anode of the picture tube and the anode cap to either the metal chassis, CRT shield, or carbon
painted on the CRT.
the anode cap. Short between anode and coated earth ground strap of CRT.
NOTE: After removing the anode cap, short circuit the anode of the picture tube and the anode cap to either the metal chassis, CRT shield, or carbon
painted on the CRT.
REMOVAL PROCEDURES
HOW TO HANDLE AN ANODE CAP
1. Do not use sharp objects which may cause damage to the surface of the
anode cap.
2. To avoid damaging the anode cap, do not squeeze the rubber covering too
hard. A material fi tting called a shatter-hook terminal is built into the rubber.
3. Do not force turn the foot of the rubber cover. This may cause the shatter-
hook terminal to protrude and damage the rubber.
Turn up one side of the rubber cap in
the direction indicated by arrow a .
the direction indicated by arrow a .
Use your thumb to pull the rubber
cap fi rmly in the direction indicated
by arrow b .
cap fi rmly in the direction indicated
by arrow b .
When one side of the rubber cap separates from
the anode button, the anode cap can be removed
by turning the rubber cap and pulling it in the
direction of arrow c .
the anode button, the anode cap can be removed
by turning the rubber cap and pulling it in the
direction of arrow c .
a
b
Anode Button
c
2
5
9
10
7
8
6
3
1
4
1 Discharge the anode of the CRT and remove the
anode cap.
2 Unplug all interconnecting leads from the defl ection
yoke, neck assembly, degaussing coils and CRT
grounding strap.
grounding strap.
3 Remove the CV Board from the CRT.
4 Remove the chassis assembly.
5 Loosen the neck assembly fi xing screw and
remove.
6 Loosen the defl ection yoke fi xing screw and
remove.
7
Place the set with the CRT face down on a cushion
and remove the degaussing coil holders.
8
Remove the degaussing coils.
9
Remove the CRT grounding strap and spring
tension devices.
10
Unscrew the four CRT fi xing screws [located on
each CRT corner] and remove the CRT. [Take care
not to handle the CRT by the neck tube.]
not to handle the CRT by the neck tube.]
KV-21FX250/21FX250A/21FX250C
KV-21FX250/21FX250A/21FX250C
12
The following adjustments should be made when a complete realignment
is required or a new picture tube is installed.
is required or a new picture tube is installed.
These adjustments should be performed with rated power supply voltage
unless otherwise noted.
unless otherwise noted.
Set the controls as follows unless otherwise noted:
Picture control
Picture control
NORMAL
Brightness control NORMAL
SECTION 2: SET-UP ADJUSTMENTS
Perform the adjustments in order as follows:
1.
1.
Beam
Landing
2.
Convergence
3.
Focus
4.
Screen
(G2)
5.
White
Balance
Note Test Equipment Required:
1.
Color Bar Pattern Generator
2.
Degausser
3.
DC Power Supply
4.
Digital
Multimeter
2-1. BEAM LANDING
Before beginning adjustment procedure:
1. Feed in the white pattern signal.
2. In order to reduce the geomagnetism on the set’s picture tube, face
it east or west.
Adjustment Procedure
1. Input a raster signal with the pattern generator.
2. Loosen the defl ection yoke mounting screw, and set the purity
control to the center as shown below:
Purity control
3. Turn the raster signal of the pattern generator to green.
4. Move the defl ection yoke backward, and adjust with the purity
control so that green is in the center and red and blue are even on
both sides.
both sides.
Red
Blue
Green
5. Move the defl ection yoke forward, and adjust so that the entire
screen becomes green.
6. Switch over the raster signal to red and blue and confi rm the
condition.
7. When the position of the defl ection yoke is determined, tighten it
with the defl ection yoke mounting screw.
8. If landing at the corner is not right, adjust by using the disk
magnets.
Purity control
corrects this area.
corrects this area.
Disc magnets or rotatable
disc magnets correct these
areas (a-d).
disc magnets correct these
areas (a-d).
Deflection yoke positioning
corrects these areas.
corrects these areas.
a
b
b
c
c
d
d
a
5.
Oscilloscope
6.
Landing
Checker
7.
XCV
Adjuster
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