Panasonic CT-20SX10B Schematic
ORDER NO. MTNC000855C1
B1
Service Manual
Color Television
Main Manual
(MJ4M)
Panasonic
Models
Chassis
CT-20SX10B AP354
CT-20SX10CB AP354
CT-24SX10B AP353
CT-24SX10CB AP353
CT-F2110XB XP353
CT-F2510XB XP353
This Service manual i s issued as a service guide for the model s of the MJ4M family listed above. Incl uded in this
manual are a set of schematic, block diagrams, functional descriptions, alignment procedures, disassembly
procedures, and a complete parts list.
“WARNING! This Service Manu al is des igned for ex perienced re pair tech nicians only and is no t designed for use by the general public.
It does not contain warnings or cautions to advise non-technical individuals of potential dangers in attempting to service a product.
Products powered by electricity should be se rviced or repaired only by experienc ed professional tec hnician s. Any a ttem pt to
service or repair the product or products dealt with in this Service Manual by anyone else could result in serious injury or death.”
The service technician is required to read and follow the “Safety Precautions” and “Important Safety Notice” in this Main Manual.
Copyright 2000 by Matsushita Electric Corporation of
America. All rights reserved. Unauthorized copying
and distribution is a violation of law.
®
Important Safety Notice
Special components are used in this television set which are important for safety. These parts are identified on the
schematic diag ram by the s ymbol and printed in BOLD TYPE o n the replac ement part l ist. It is es senti al that
these critical parts are replaced with the manufacturer’s specified replacement part to prevent X-ray radiation,
shock, fire or other hazards. Do not modify the original design without the manufacturer’s permission.
Safety Precautions
General Guidelines
An Isolation Transformer should always be used
during the servicing of a r eceiver whose c hassis is not
isolated from AC power line. Use a transformer of
adequate power rating as this protects the technician
from accidents resulting in personal injury from
electrical shocks. It will also protec t the Receiver from
being damaged by accidenta l shorting that may occur
during servicing.
When servicing, observe the original lead dress,
especially in the high voltage circuit. Replace all
damaged parts (also parts that show signs of
overheating.)
Always Replace Protective Devices, such as
fishpaper, isolation resistors and capacitors, and
shields after servicing the Receiver. Use only
manufacturer ’s recommended rating for fuses, c ircuits
breakers, etc.
High potentials are present when this Receiver is
operating. Operation of the Receiver without the rear
cover introduces danger for elect rical shock. S ervicing
should not be performed by anyone who is not
thoroughly familiar with the necessary precautions
when servicing high-voltage equipment.
Extreme care should be practiced when Handling the
Picture T ube. Rough handling may cause it to implode
due to atmospheric pres sure. (14.7 lbs per sq. in.). D o
not nick or scratch the glass or subject it to any undu e
pressure. When handling, use safety goggles and
heavy gloves for protection. Discharge the picture
tube by shorting the anode to chassis ground (not to
the cabinet or to other mounting hardware). When
discharging con nec t co ld ground (i.e. dag ground lead)
to the anode with a well insulated wire or use a
grounding probe.
Avoid prolonged exposure at close range to unshielded
areas of the picture tube to prevent exposure to
X-ray radiation.
The Test Picture Tube used for servicin g the chassis
at the bench should incorporate safety glass and
magnetic shieldi ng. The safety glass pro vide shielding
for the tube viewing area against X-ray radiation as
well as implosion. The magnetic sh ield limits the X-ray
radiation around the bell of the pict ure tube in addition
to the restricting magnetic effects. When using a
picture tube test jig for service, ensure that the jig is
capable of handling 50.0kV without causing
X-ray radiation.
Before returning a serviced rec eiver to the owner,
the service technic ian must thoroughly test the unit to
ensure that is completely safe to operate. Do not use a
line isolation transformer when testing.
Leakage Current Cold Check
Unplug the AC cord and connect a jumper between the
two plug prongs.
Measure the resistance between the jumpered AC plug
and expose metallic parts such as screwheads,
antenna terminals, control shafts, etc. If the exposed
metallic part has a return path to the chassis, the
reading should be between 240kΩ and 5.2MΩ. If the
exposed metallic part does not have a return path to
the chassis, the reading should be infinite.
Leakage Current Hot Check (Fig. 1)
Plug the AC cord directly into the AC outlet. Do not use
an isolation transformer during the check.
Connect a 1.5kΩ 10 watt resistor in parallel with a
0.15µF capacitor between an exposed metallic part
and ground. Use earth ground, for example a
water pipe.
Using a DVM with a 1000 ohms/volt sensitivity or
higher, measure the AC potential across the resistor.
Repeat the procedure and measure the voltage
present with all other exposed metallic parts.
Verify that any potential does not exceed 0.75 volt
RMS. A leakage curr ent tes ter (suc h a S impson M odel
229, Sencore Model P R57 or equiv alent) may be used
in the above procedure, in which case any current
measure must not exceed 1/2 milliamp. If any
measurement is out of the specified limits, there is a
possibility of a s hock haz ar d and th e R ece iv er m us t b e
repaired and rechecked before it is returned to the
customer.
AC VOLTMETER
COLD
WATER
PIPE
(GROUND)
0.15µF
TO INSTRUMENT’S
EXPOSED METAL
PARTS
1500Ω,10 W
Figure 1. Hot Check Circuit
X-ray Radiation
WARNING: The potential source of X-ray radiation in the
TV set is in the H igh Vol ta ge sect ion an d the p ict ur e tu be.
Note: It is important to use an accurate, calibrated
high voltage meter.
Set the brightness, picture, sharpness and color
controls to Minimum.
Measure the High Voltage. The high voltage shou ld be
30.55kV ± 1.25kV for 25in models and 28.80kV ±
1.25kV for 20in models. If the upper limit is out of
tolerance, immediate service and correction is required
to insure safe operation and to prevent the possibility of
premature component failu re.
- 2 -
Important Safety Notice . . . . . . . . . . . . . . . . . . 2
Safety Precautions . . . . . . . . . . . . . . . . . 2
Service Notes. . . . . . . . . . . . . . . . . . . . . . . . . . . 4
X-ray Protection Circuit Test. . . . . . . . . . 5
Helpful Hints . . . . . . . . . . . . . . . . . . . . . 20
Sub-Data Adjustment . . . . . . . . . . . . . . 21
Cut-Off Adjustment . . . . . . . . . . . . . . . . 21
Geometric Adjustment . . . . . . . . . . . . . 22
S Options Adjustment. . . . . . . . . . . . . . 22
Geomagnetic Adjustment . . . . . . . . . . . 23
Instructional Flow Chart
for Serviceman Mode . . . . . . . . . . . . . . . . 24
Receivers Feature Table . . . . . . . . . . . . . . . . . . 6
Board Designation. . . . . . . . . . . . . . . . . . . . . . . 7
Location of Controls (Receiver)
Receiver Front Control Panel . . . . . . . . . 8
Location of Controls (Remote)
EUR511502 . . . . . . . . . . . . . . . . . . . . . . 9
Disassembly for Service. . . . . . . . . . . . . . . . . 10
Boards Removal. . . . . . . . . . . . . . . . . . 10
Disassembly for CRT Replacement . . . . . . . . 10
Identification of Main components . . . . . . . . .11
Purity and Convergence Procedures . . . . . . 15
Chassis Service Adjustment Procedures . . . 18
140.0V B+ Voltage Confirmation . . . . . 18
Source Voltage Chart . . . . . . . . . . . . . . 18
High Voltage Check . . . . . . . . . . . . . . . 19
Deflection Circuit Pre-adjustment. . . . . 19
Service Adjustments
(Electronic Control). . . . . . . . . . . . . . . . . . 27
Sub-Brightness. . . . . . . . . . . . . . . . . . . 27
Sub-Contrast. . . . . . . . . . . . . . . . . . . . . 27
Tint/Color Adjustment . . . . . . . . . . . . . . 27
Color Temperature Adjustment (W/B). . 28
Complete Adjustment . . . . . . . . . . . . . . 28
Horizontal Centering. . . . . . . . . . . . . . . 29
E-W Pincushion . . . . . . . . . . . . . . . . . . 29
Horizontal Width . . . . . . . . . . . . . . . . . . 29
Vertical Position . . . . . . . . . . . . . . . . . . 29
Vertical Linearity . . . . . . . . . . . . . . . . . . 30
Vertical Correction.. . . . . . . . . . . . . . . . 30
MTS Circuit Confirmation . . . . . . . . . . . 30
Audio Signal Path Block Diagram. . . . . 32
Video-Chroma Signal Path
Block Diagram . . . . . . . . . . . . . . . . 33
IC001 MPU IN/OUT
Pins and Functions. . . . . . . . . . . . . 34
IC101 VCJ IN/OUT
Pins and Functions. . . . . . . . . . . . . 35
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Serviceman Mode (Electronic Controls) . . . . 20
Entering Serviceman Mode . . . . . . . . . 20
Toggle between Modes. . . . . . . . . . . . . 20
Exiting the Serviceman Mode. . . . . . . . 20
Purity Check . . . . . . . . . . . . . . . . . . . . . 20
- 3 -
Service Notes
Chip Components
TRANSISTOR
CAPACITOR
RESISTOR
MH DIODE
SOLDER
CAPS
SOLDER
CAPS
1ST DIGIT
2ND DIGIT
MULTIPLIER
=1600 = 1.6k
GRADE
TYPE
COMMON
ANODES
CATHODE
Note: These components are affixed with glue. Be careful not to break or damage any foil under the
component or at the pins of the ICs when removing. Usually applying heat to the component for a
short time while twisting with tweezers will break the component loose.
Leadless Chip Component
(surface mount)
Chip components must be replaced with identical chips
due to critical foil tr ack spacing. There are no ho les in
the board to mount standard transistors or diodes.
Some chips capacitor or resistor board solder pads
may have holes thr ough the board, however the hole
diameter limits standard resistor replacement to 1/8
watt. Standard capacitor may also be limited for the
same reason. It is recommended that identical
components be used.
Chip resistor have a three digit numerical resistance
code - 1st and 2nd significant digits and a multiplier.
Example: 162 = 1600 or 1.6kΩ resistor, 0 = 0Ω (jumper).
Chip capacitors generally do not have the value
indicated on the capacitor. The color of the compo nent
indicates the general range of th e capacitance.
Chip transistors are id enti fied by a two letter code. The
first letter indicates the type and the second l etter, the
grade of transistor.
Chip diodes have a two lette r i den tif ic ati on code as per
the code chart an d are a dual diode pack with either
common anode or common cathode. Check the parts
list for correct diode number.
Component Removal
1. Use solder wick to remove s older fr om compo nent
end caps or terminal.
2. Without pulling up, carefully twist the component
with tweezers to break the adhesive.
3. Do not reuse removed leadless or chip
components since they are subject to stress
fracture during removal.
Chip Component Installation
1. Put a small amount of solder on the board
soldering pads.
2. Hold the chip component against the soldering
pads with tweezers or with a miniature alligator clip
and apply heat to the pad area with a 30 watt iron
until solder flows. Do not appl y heat for more than
3 sec onds.
How to Replace Flat-IC
- Required Tools -
• Soldering iron • De-solder braids
• Iron wire or small awl • Magni fier
1. Remove the solder from all of the pins of a Fla t-IC
by using a de-solder braid.
De-Solder
Flat-IC
2. Put the iron wire under the pins of the Flat-IC an d
pull it in the direction indicated while heating the
pins using a soldering iron. A small awl can be
used instead of the iron wire.
Iron
Wire
Pull
Soldering
Iron
Soldering
Iron
3. Remove the solder from all the pads of the Flat- IC
by using a de-solder braid.
Soldering
Iron
De-Solder
Braid
Flat IC
4. Position the new Flat-IC in pl ace (apply the pins of
the Flat-IC to the soldering pads where the pins
need to be soldered). Properly determine the
positions of the soldering pads and pins by
correctly aligning the polarity symbol.
Polarity Symbol
Braid
Awl
b
e
c
123.....
5. Solder all pins to the soldering pads using a fine
tipped soldering iron.
Solder
Soldering
Iron
6. Check with a magnifier fo r solder bridge between
the pins or for d r y jo int b e twe en pi ns a nd s old er in g
pads. To remove a solder bridge, u se a de-solder
braid as shown in the figure below.
De-Solder
Braid
Solder
Bridge
Soldering
Iron
- 4 -
Service Notes (Continued)
IMPORTANT: To protect against possible damage to
the solid state devices due to arcing or static discharge,
make certain that all ground wires and CTR DAG wire
are securely connected.
CAUTION:
The power supply circuit is above earth ground and the
chassis cannot be polarized. Use an isolation
transformer when servicing the Receiver to avoid
damage to the test equipment or to the chassis.
Connect the test equipment to the proper ground
(Hot ) or (Cold ) when servicing, or incorrect
voltages will be measured.
WARNING:
This Receiver has been designed to meet or exceed
applicable safety and X-ray radiation protection as
specified by government agencies and independent
testing laboratories.
To maintain original product safety design standards
relative to X-ray radiation and shock and fire hazard,
parts indicated with the s ymbol on the schematic
must be replaced with identical parts. Order parts from
the manufacturer’s parts center using the parts
numbers shown in t his service manual, or provide the
chassis number and the part reference number.
For optimum performanc e and rel iability, all other parts
should be replaced with components of
identical specification.
X-RAY PROTECTION CIRCUIT TEST
Preparation
1. Connect a High voltage mete r (Capable of handle
50kV) to the CRT anode
2. Connect a variable resistor (3K) in series with a
100 ohms resistor, across (in parallel) R849.
3. Connect a jumper in R850 position (make a short
on R850).
Procedure:
1. Plug receiver to120V ac. and turn it on.
2. Apply a monoscope pattern.
3. Set PICTURE and BRIGHTNESS to normal.
4. Set variable resistor to maximum level (3k)
5. Slowly decrease variable resistor value.
6. Adjust beam current between 50µA and 100µA
with the SCREEN VR of FBT.
7. Adjusting the Variable REsistor, check if the set
starts to loose synchrony
8. Confirm the reading fr om the High Voltage meter
is 38KV for 25” models and 34KV for 20”
models.
9. Turn Off the receiver and remove the jumper.
- 5 -
Receiver Feature Table
FEATURE\MODEL
Chassis MJ4M MJ4M MJ4M MJ4M
# of channels 181 181 181 181
Menu language ENG/ESP/FR ENG/ESP/FR ENG/ESP/FR ENG/ESP/FR
Closed Caption XXXX
V-Chip (USA/CANADA) XXXX
75 Ohm Input XXXX
Remote Model # EUR511502 EUR511502 EUR511502 EUR511502
Picture tube A68LUQ085X A68LUQ085X A68LUQ085X A68LUQ085X
Flat (4:3) (4:3) (4:3) (4:3)
Comb Filter 3 Dig 3 Dig 3 Dig 3 Dig
VM XXXX
Color Temp XXXX
V/A norm (X=both) XXXX
MTS/SAP/DBX XXXX
Built-in audio power 7W/CH(10%) 7W/CH(10%) 7W/CH(10%) 7W/CH(10%)
# of speakers 2222
Speaker T y pe Open Dome Open Dome Open Dome Open Dome
CT-24SX10B &
CT-24SX10CB
CT-20SX10B &
CT-20SX10CB
CT-F2510XB CT-F2110XB
Bass/Bl/Tre Control XXXX
AI Sound XXXX
Surround XXXX
A/V in (rear/front) 3(2/1) 3(2/1) 3(2/1) 3(2/1)
Component Input 1111
Audio Out (FAO,VAO) F,V F,V F,V F,V
S-VHS Input (rear/front) 2(1/1) 2(1/1) 2(1/1) 2(1/1)
EPJ/HPJ/MISC HPJ HPJ HPJ HPJ
Dimensions mm
(HxWxD) in
Weight (kg/lbs) 36.09/79.4 25/55 36.09/79.4 25/55
Power source (V/Hz) 120/60 120/60 120/60 120/60
Anode voltage 30.55kV±1.25kV 28.8kV±1.25kV 30.55kV±1.25kV 28.8kV±1.25kV
Video input jack
Audio in put jack 500mV RMS 47kΩ 500mV RMS 47kΩ 500mV RMS 47kΩ 500mV RMS 47kΩ
636x720x573
24.46x27.69x22.3
75Ω phono jack 1 V
1 V
p-p
570x638x569
21.92x24.53x21.88
75Ω phono jack 1 V
p-p
636x720x573
24.46x27.69x22.3
75Ω phono jack 1 V
p-p
570x638x569
21.92x24.53x21.88
75Ω phono jack
p-p
Table 1. Receiver Features
Specifications are subject to change without notice or obligation.
Dimensions and weights are approximate.
- 6 -
Board Designation
Board Part No.
A-Board TNP2AH022 AB AC AE AF Main Chassis
C-Board TNP2AA068 AB AC AB AC CRT Drive
G-Board TNP2AA071 AB AC AB AC Audio Circuit
H-Board TNP2AA070 AA AA AA AA
Q-Board TNP2AA067 AB AC AB AC H-Drive
CT-24SX10B &
CT-24SX10CB
CT-20SX10B &
CT-20SX10CB
CT-F2510XB CT-F2110XB
Description
A/V Input
Switch
IMPORTANT
When ordering boards, please add an “S” to the
part number, for example TNP2AH022AA should
be ordered as TNP2AH022AAS.
- 7 -
Location of Controls (Receiver)
1
Remote Control
Sensor
ACTION TV/VIDEO VOLUME CHANNEL
1
Power Button - Press to turn ON or OFF.
Volume Buttons - Press to adjust Sound Level, or to adjust Audio Menus, Video
2
Menus, and select operating features when menus are displayed
Channel Buttons - Press to sele ct programme d channels. Pre ss to highlig ht desired
features when menus are dis play ed. Also us e to selec t Cable Conv erte r box chan nels
3
after programming Remo te Control Infrared codes (the TV/AUX/C ABLE switch must
be set in CABLE position).
3254
S-VHS
INPUT
A/V INPUT
Figure 2. Location of Controls Receiver
Quick Reference Control Operation
Quick Reference
Control Operation
HPJ
Action Button - Press to display Main Menu and access On Screen feature and
4
Adjustment Menus.
5
TV/Video Button - Press to select TV or any Video Input, for the Main Picture
- 8 -
Location of Controls (Remote )
POWER Button
Press to turn ON and OFF.
MUTE Button
Press to mute sound.
A second press resumes sound.
Press also to access and delete
Closed Caption display.
VCR, DVD, TV, CBL, DBS
Component function buttons
VOL (volume) Buttons
Press to adjust TV sound level.
Use with Channel buttons to
navigate in menus.
R-TUNE (Rapid Tune) Button.
Press to switch to the previous
channel.
ACTION Button
Press to display Main Menu and
access or exit On Screen features
and Adjustment Menus.
LIGHT
Press to light Remote control buttons
TV/VIDEO Button
Press to select TV or any Video input.
CH (channel) Buttons
Press to select channels.
Use with volume buttons to
navigate in menus.
DBS EXIT, DBS GUIDE
DBS function buttons.
RECALL Button
Press to display Time, status
of Sleep Timer, Channel,
Video mode and Channel
Caption (Station Identifier).
“0” - “9”
Press numeric keypad to select any
channel.
REW, PLAY, FF, TV/VCR, STOP,
PAUSE, REC, VCR CHANNEL
Component function buttons.
For more functions and information about this
Remote Control, refer to the Remote Guide listed
in Parts List of this manual
EUR511502
Figure 3. Location of Controls (Remote)
- 9 -
Disassembly for Service
Back Cover
Remove all the screws marked with an arrow( )
from the back of the Receiver.
Note: Screw configuration, type, and number of
screws vary depending on the model of the
Receiver serviced and the app lication; various
models are covered in this Manual. Use same
hardware when reassembling the receiver.
• 3 screws at the top edge of the Receiver.
• 1 screw at each lower corner of the Receiver.
• 2 screws by the A/V bracket top edge.
• 1 screw by the A/V bracket bottom edge.
H-Board - A/V Jacks, S-Video Connectors
and Video Switch
Plugs onto the A-Board at the A11 (H11) connector
Q-Board - Horizontal Drive
Plugs onto the A-Board at the A6, A7 and A8
(QC6, QC7 and QC8) connectors. Is secured to
Q551 heat sink by two screws.
Note: Use a small flat head screwdriver to
release the connector locking tabs.
Speaker Dome
Each speaker is se cu re d to the fr ont ca bin et wi th 2
screws. (See Fig. 6)
A-Board - Main Chassis (See Fig. 5)
The Q and H-Board are assembled on the Main
chassis (A-Board). When servicing these boards,
extension cables may be required. Cables kit can be
ordered from Matsushita Se rvices C ompany, see Parts
List for parts number. The A-Board assembly rest on a
chassis tray along with the G-Board.
Slide chassis tray out. Gently lift, tray and pull out.
Disconnect plug connectors; release wire ties and
holders as required for complete chassis removal.
• A-Board is secured to the chassis tray with 8
screws.
• The G-Board is secured to the chassis tray with 5
screws
• The A-Board is mated to the G-Board with to
flexible connectors: A22 & A23 (G2 and G3 on the
G-Board, respectively). To remove either boards,
unplug the connectors on the A-Board.
Note: Some tie-wraps that secur e the wir e dressings
may need to be unfastened for chassis
removal.
C-Board - CRT Output
Plugs into the socket on the CRT neck.
To unplug Screen and Focus cables from CRT
socket, lift the tabs on the socket and pull the
cables as shown. To plug cables, close the tabs
then insert the cable.
Figure 4. Focus and Screen cables.
Disassembly for CRT
Replacement
1. Discharge the CRT as instructed in the Safety
Precautions (see page 2) and rem ove 2nd anod e
button from the CRT.
2. Remove Speaker Modules (R & L)
3. Disconnect:
A-Board = Deflection Yoke (DY), Deg. Coil
G-Board = Speakers (G8),
C-Board = C2 Conv. Yoke, C1 DAG GND.
4. Remove Convergence and Deflection Yoke from
CRT neck.
5. Perform complete removal of the Main Chassis,
G-Board and CRT-Board as instructed in
Disassembly for Service.
CRT Replacement
1. Perform Disassembly for CRT Replacement
procedure.
2. Insure that the CRT H.V. Anode button is
discharged before handling the CRT. Read the
Safety Precautions (see page 2) on handling the
picture tube.
3. Remove the components from the CRT neck and
place the cabinet face down on a soft pad.
4. Note the original order for the CRT mounting
hardware as they are remove from the CRT
mounting brackets at each corner of the CRT.
5. Remove the CRT with the dega ussing co il and th e
dag ground braid attached.
6. Note the original locations and mounting of the
degaussing coil and the dag ground assembly to
insure proper reinstallation on the replacement
CRT.
To remove and remount the degaussing coil:
The degaussing co il is held in place by clampers
fastened to the CRT corner ears. These c lampers
must be installed onto th e replacement CRT prior
to mounting the degaussing coil.
To remove and remount the dag ground braid:
a.Unhook the coil sprin g from the bottom corners
of the CRT ears.
b.Release the braid loop from the upper corners of
the CRT ears.
7. Mount the dag ground braid on the replacement
CRT. Position the degaussing coil with new ties.
Dress coil as was on the original CRT.
8. Replace the components on CRT neck and
reinstall into cabinet. Verify that all ground wires
and circuit board plugs get connected.
- 10 -
Identification of Main Components
CRT
Secured to Cabinet
by 4 screws on corners
Anode
(High Voltage)
Deflection Yoke C-BoardYo ke Wedges
Speaker
Dome
Deg Coil
Tuner
H-Board Q-Board
Figure 5. Components Identification
A-Board
Main Chassis
DAG Gnd.
T551
Flyback
Note:
After servicing the receiv er, remember
to dress the cables, as shown above.
- 11 -
Identification of Main Components
Speaker Dome
After servicing the receiver, remember
to dress the AC cord as shown
Figure 6. RECEIVER REAR VIEW DETAIL
Note:
Figure 7.
After servicing the receiver, remember
to dress the cables, as shown above.
- 12 -
Identification of Main Components
8
14
15
16
4
11
10
2
12
3
13
6 7
17
9
Figure 8. View of Main Board Assemblies.
NO. LOCATION OF COMPONENTS
INTEGRATED CIRCUITS 7IC005 OTHERS
1 IC001 MPU 8IC80112 Tuner
2 IC6501 Comb Filter CONNECTORS 13 Fuse
3 IC101 VCJ 9 A22,A23 14 Relay
4IC 451 10 A11 15 D801
5IC 002 TRANSISTORS 16 T551 FBT
6 IC 811 COUPLER 11 Q551 17 T801
5
1
- 13 -
Identification of Main Components
CRT Socket Q955 Q950IC351
C-Board
G-Board
H-Board
H4 H5 H6
H11
IC2301 IC2302
Remote
Sensor
IC2352
Power
Bottom
IC2401
IC750
Q755
Q754
Q501
Q-Board
Figure 9. C, H, G and Q Board Main Components.
- 14 -
Purity and Convergence Procedure
G3 G4
Adjustment is necessary only if the CRT or the
deflection yoke is replaced or if the setting was
disturbed. The complete procedure consists of:
1. Vertical Raster Shift Adjustment.
2. Initial static convergence.
3. Setting the purity.
4. Final static convergence.
When the CRT or the Yoke is Replaced
Place the yoke on the CRT neck (do not tighten
the clamp).
Position purity/convergence assembly as shown and
tighten clamp snugly. Remove the hot-melt glue seal
on assembly and position like tabs of purity device
together at 12 o’clock to reduce its magnetic field
effect.
Place the vertical raster shift tabs at 3 o’clock (90
the purity and convergence tabs, see Fig. 10 and
Fig. 11
)
R&B Convergence Rings
R&B&G Convergence Rings
Vertical Raster Shift Ring
Over G3/G4 Gap
o
from
Vertical Raster Shift Adjustment
Apply a green pattern with a horizontal line, adjust the
Deflection Yoke so that has no tilt, then secure it.
Adjust center line of the pattern with the mechanical
center of the CRT, this center is determined by two
marks at the side edges of the screen. To adjust the
line, once the vertical raster shift tabs are place at 3
o’clock to reduce i ts magnetic field effect (see Fig. 10
and Fig. 11) open the tabs the same angle from the
center, until the center line of the pattern becomes a
straight line, center ed with the marks of the CRT. ( see
Fig. 12)
Center line
from pattern
Mechanical
Center Marks
Vertical Raster Shift tabs
Figure 12. Vertical Raster Shift Adjustment
Open the
same angle
from center
Purity Rings
Figure 10. Positioning of Purity/Convergence
Assembly
R&B&G Convergence Rings
R&B Convergence Rings
Vertical Raster
Shift Rings
Purity Rings
90
o
Figure 11. Positioning of Purity/Convergence
Assembly
Turn the Receiver ON. Operate the Receiver for 60
minutes using the first Purity Check field (white screen)
to stabilize the CRT.
Fully degauss the Receiver by using an external
degaussing coil.
Slide the deflection yoke bac k and forth on t he neck of
the CRT until it produces a near white, uniform raster.
Initial Center Static Convergence
Connect a dot/cross hatch generator to the Receiver
and tune in a signal. Observe misconvergence at
center of the screen only.
Adjust the R&B pole magnets; b y separating tabs an d
rotating to converge blue with red.
Adjust the R&B and R&B&G pole magnets: by
separating tabs and rotating to converge blue an d red
(magenta) with green.
Note: Precise convergence at this point is
not important.
Purity Adjustment
When the Receiver is in the Serviceman Mode for
making electronic adjustments, press the Recall button
on the Remote Control to enter Purity Ch eck. (See th e
Service Adjustments Electronic Controls
procedure).
Operate the Receiver for 60 minutes using the first
Purity Check field (white screen) to stabilize the CRT.
Fully degauss the Receiver by using an external
degaussing coil.
Press the Recall button on the Remote Control again
until the Purity Check (green screen) appears.
Loosen the deflection yoke clamp screw an d move the
deflection yoke back as close to the purity magnet
as possible.
- 15 -
Adjust the Purit y rings to set the vertical green raster
NOTES:
1. CRT warm up with white screen
(three guns activated) is needed
to stabilize the shadow mask
expansion.
2. Initial center static convergence
(roughly centers three gun
beams) is required in order to
perform purity adjustment.
Figure 13. Green Raster Adjustment
Green Raster
precisely at the center of the screen (see Fig. 13).
Slowly move the deflecti on yoke forward until the best
overall green screen is displayed.
Tighten the deflection yoke clamp screw.
Press the Recall button on the Remote Control again
until the purity check (blue screen) and (red screen)
appear and observe that good purity is obtained on
each respective field.
Press the Recall button on the Remote Control again
until Purity check (white screen) app ears. Obse rve the
screen for uniform white. If purity has not been
achieved, repeat the above procedure.
Final Convergence Procedure (see Fig. 14
through Fig. 16):
Note: Vertical size and focus adjustments must be
completed prior to performing the convergence
adjustment. Connect a dot pattern generator to the
Receiver. The Brightness level should not be h igher
than necessary to obtain a clear pattern.
Converge the red and the blue dots at the center of the
screen by rotating the R&B pole Static Convergence
Magnets.
Align The converged red/blue dots with the green dots
at the center of the screen by rotating the R&B&G pol e
Static Convergence Magnets. Melt wax with soldering
iron to reseal the magnets.
Slightly tilt vertica lly and ho rizontally (do not ro tate) the
deflection yoke to obtain a good overall convergence.
If convergence is not reached at the edges, insert
permalloy (see fo llowing section) from the DY corners
to achieve proper convergence. Recheck for purity and
readjust if necessary.
After vertical adjustment of the yoke, insert wedge at 11
o’clock position, then make the horizontal
tilt adjustment.
Secure the deflection yoke by inserting two side
wedges at 3 and 7 o’clock positions.
Apply adhesive between tab (thin portion) of wedge
and CRT and place tape over the tab to secure to
the CRT.
Permalloy Convergence Corrector Strip
(Part No. 0FMK014ZZ)
This strip is used in some sets to match the yoke and
CRT for optimum convergence. If the y oke or CRT is
replaced, the strip may not be required.
First converge the set without the strip and observe
the corners.
If correction is needed:
1. Place strip between CRT and yoke, in quadrant
needing correction. Slowly move it around for
desired results.
2. Press adhesive tightly to the CRT and secure
with tape.
- 16 -
As the yoke is tilted
RGB
Figure 14. Vertical Yoke Movement
vertically, the rasters
produced by the
outside guns rotate in
opposite directions.
RGB
As the yoke is tilted horizontally, one
raster gets larger while the other gets
smaller
Figure 15. Horizontal Yoke Movement
Raster produced from one of the
outside electron beams
Raster from the other side electron
beam
Static convergence magnets are set for
center convergence
Static Convergence Magnets
Converges
R/B with G
Purity/Convergence
Assembly Clamp
Converges
R with B
Vertical Raster Shift
Figure 16. Convergence Magnets and Wedges Location
11 o’clock Position
Purity Rings Adj. on
Green Raster
Double sided adhesive tape
3 o’clock Position
Y oke Positioning Wedges
for Dynamic Convergence
7 o’clock Position
- 17 -
Chassis Service Adjustment Procedures
All service adjustments are factory preset and should not require adjustment unless controls and/or
associated components are replaced.
Note: Connect the (-) lead of the voltmeter to the appropriate ground. Use IC801’ s heat sink when the HOT ground
symbol ( ) is used. Otherwise, use COLD ground ( ) — T uner shield, IC451’s heat sink or FA2(TP-3).(See Fig. 8)
Q551
COLD GND ( )
HOT GND ( )
F801
DY
IC451
T801
Q451
TPA146
C837
C849
A11
D841
IC882
TPD72
C6501
C563
TPD76
IC891
TPA143
C038
18
COMB FILTER
IC6501
MPU
IC001
TP
T
U
N
E
R
IC101
140.0V B+ Voltage Confirmation
1. Set the Bright, Picture and Color to Minimum by
using the Picture Menu.
2. Connect the DVM between C849, + side (A-Board)
and cold ground ( ).
3. Confirm that B+ voltage is 140.0V ± 1.5V. This
voltage supplies B+ to the Horizontal Output &
Flyback circuits.
Source Voltage Chart
120V AC line input. Se t the Bright and the Picture to
(
Minimum by using the Picture Menu . Use cold
Hot ( ) ground for the (-) lead of the DVM as needed.
) or
LOCATION
(A-Board)
TPD72
C837 (+)
TPA143
TPD76
TPA146
C6501 (+)
C038 (+)
VOLTAGE
± 2 V DC
24
13.0 ± 2 V DC
9.0 ±1 V DC
± 0.5 V DC
12.0
5.0 ± 0.25 V DC
5.0 ± 0.25 V DC
± 0.1 V DC
3.3
Set all adjustments to normal level.
- 18 -
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