Sony KV-28WF1A Service Manual ▷ View online
KV-28WF1
— 21 —
2-4. WIRE DRESSING
2-5. A BOARD REMOVAL
A board.
2-6. A EXTENSION BOARD
BE-3D EXTENSION BOARD
A board
KV-28WF1
— 22 —
2-7. PICTURE TUBE REMOVAL
Two DGC holers
Anode cap
•
REMOVAL OF ANODE-CAP
Note:
Short circuit the anode of the picture tube and the anode cap to the metal chassis, CRT shield or
carbon paint on the CRT, after removing the anode.
b
b
Anode button
a
* REMOVING PROCEDURES.
c
Turn up one side of the rubber cap in
the direction indicated by the arrow a
the direction indicated by the arrow a
1
2 Using a thumb pull up the rubber cap
firmly in the direction indicated by the
arrow b
arrow b
3
When one side of the rubber cap is
separated from the anode button, the
anode-cap can be removed by turning
up the rubber cap and pulling it up in
the direction of the arrow c
separated from the anode button, the
anode-cap can be removed by turning
up the rubber cap and pulling it up in
the direction of the arrow c
•
HOW TO HANDLE AN ANODE-CAP
Don't damage the surface of anode-cap with sharp shaped material !
Don't press the rubber hardly not to hurt inside of anode-caps !
A metal fitting called as shatter-hook terminal is built into the rubber.
Don’t turn the foot of rubber over hardly !
The shatter-hook terminal will stick out or damage the rubber
Don't press the rubber hardly not to hurt inside of anode-caps !
A metal fitting called as shatter-hook terminal is built into the rubber.
Don’t turn the foot of rubber over hardly !
The shatter-hook terminal will stick out or damage the rubber
.
1
2
3
Cushion
Chassis assy
Spring extension
Four PT screws
Picture tube
6
4
9
1
10
Degaussing coil
7
2
Deflection yoke
5
Neck assy
8
3
C board
KV-28WF1
— 23 —
REMOVAL AND REPLACEMENT OF THE MAIN-BRACKET
BOTTOM PLATES.
BOTTOM PLATES.
(1) REMOVING THE PLATES
In the event of servicing being required to the solder side of the D Board printed
circuit, the bottom plates fitted to the main chassis bracket require to be removed.
This is performed by cutting the gates with a sharp wire cutter at the locations
shown and indicated by arrows.
circuit, the bottom plates fitted to the main chassis bracket require to be removed.
This is performed by cutting the gates with a sharp wire cutter at the locations
shown and indicated by arrows.
Note : There are 5 plates fitted to the main bracket and secured by 4 or 6 gates.
Only remove the necessary plate to gain access to the circuit board.
FOR SAFETY REASON THIS
PLATE MUST BE REMOUNTED
AFTER CUTTING AND
TAKING AWAY.
Fig 1
For safety reasons, on no account should the plates be removed
and not refitted after servicing.
and not refitted after servicing.
Because the plates differ in size it is important that the correct plates are refitted in their
original location.
The plates are identified by markings A-B-C-D-E on their top side.
original location.
The plates are identified by markings A-B-C-D-E on their top side.
1.
Identify the plate by locating its marking.
2.
Turn the plate over noting where the marking is located.
3.
Locate the corresponding marking indicated on the main chassis bracket. See Fig 2.
4.
Refit the plate as indicated in Fig 3 with the markings located next to each other.
(2) REFITTING THE PLATES
FOR SAFETY REASON THIS
PLATE MUST BE REMOUNTED
AFTER CUTTING AND
TAKING AWAY.
ATTENTION
FOR SAFETY REASON THIS
PLATE MUST BE REMOUNTED
AFTER CUTTING AND
TAKING AWAY.
ATTENTION
E
D
INDEX MARKING
AT BRACKET FRAME
Fig 2
In the event of the plates requiring to be
removed at a later stage, this can be achieved
by inserting a screwdriver in the snap-recess
indicated as in Fig 4 and lifting out.
removed at a later stage, this can be achieved
by inserting a screwdriver in the snap-recess
indicated as in Fig 4 and lifting out.
INSERT FROM
THE BOTTOM
SIDE
THE BOTTOM
SIDE
Fig 3
MAIN BRACKET
Fig 4
KV-28WF1
— 24 —
SECTION 3
SET-UP ADJUSTMENTS
•
Carry out the following adjustments in this order :
1.
Beam landing
2.
Convergence
3.
Focus
4.
White balance
Note: Testing equipment required.
1. Color bar/pattern generator
2. Degausser
3. DC power supply
4. Digital multimeter
5. Oscilloscope
2. Degausser
3. DC power supply
4. Digital multimeter
5. Oscilloscope
•
When complete readjustment is necessary or a new
picture tube is installed, carry out the following
adjustments.
picture tube is installed, carry out the following
adjustments.
•
Unless there are specific instructions to the contrary,
carry out these adjustments with the rated power
supply.
carry out these adjustments with the rated power
supply.
•
Unless there are specific instructions to the contrary, set
the controls and switches to these settings :
the controls and switches to these settings :
Contrast ............ 80%
(or remote control
normal)
Brightness ........... 50%
Preparation:
•
In order to reduce the influence of geomagnetism on
the set's picture tube, face it east or west.
the set's picture tube, face it east or west.
•
Switch on the set's power and degauss with the
degausser.
degausser.
3-1. BEAM LANDING
1.
Input the white signal with the pattern generator.
CONTRAST
BRlGHTNESS
CONTRAST
BRlGHTNESS
2.
Set the pattern generator raster signal to red.
3.
Move the deflection yoke forward and adjust with the
purity control so that the red is at the centre and the
blue and the green take up equally sized areas on
each side. (See Fig. 3-1 - 3-3)
purity control so that the red is at the centre and the
blue and the green take up equally sized areas on
each side. (See Fig. 3-1 - 3-3)
4.
Move the deflection yoke forward and adjust so that
the entire screen becomes red. (See Fig. 3-1)
the entire screen becomes red. (See Fig. 3-1)
5.
Switch the raster signal to blue, then to green and
verify the condition.
verify the condition.
6.
When the position of the deflection yoke has been
decided, fasten the deflection yoke with the screws.
decided, fasten the deflection yoke with the screws.
7.
If the beam does not land correctly in all the corners,
use a magnet to adjust it. (See Fig. 3-4)
use a magnet to adjust it. (See Fig. 3-4)
Fig. 3-1
Fig. 3-4
G1
G2
A buckle
NECK ASSY
Deflection yoke
Purity control
Fig. 3-2
Fig. 3-3
Blue
Green
Red
normal
Deflection yoke positioning
corrects these areas.
corrects these areas.
Purity control corrects
this area.
this area.
Disk magnets or
rotatable disk
magnets correct
these areas (a - d).
rotatable disk
magnets correct
these areas (a - d).
a
b
c
d
a
c
b
d
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