This simplified service manual is issued to add listed models to the main service manual, order No. MTNC010306C1
(CT-27G6E); Models CT-27G7DF/DUF are similar to CT-27G6E. A full set of schematics, unique settings, and a com-
plete parts list are included in this simplified manual.
Please file and use this simplified service manual together with main service manual, order No. MTNC010306C1.
“WARNING! ThisServiceManual is designedfor experienced repairtechniciansonly and isnot designedfor use bythe generalpublic.
It does not contain warnings or cautions to advise non-technical individuals of potential dangers in attempting to service a product.
Products poweredby electricity should be serviced or repaired only by experienced professionaltechnicians. Any attempt to
service or repair the product or products dealt with in this Service Manual by anyone else could result in serious injury or death.”
Chassis
The service technician is requiredtoreadand follow the “Safety Precautions”and“Important Safety Notice” in this Manual.
Copyright 2001 by Ma tsus hi ta El ectr ic Cor pora tion o f Am eric a. Al l rig hts res erve d. Un auth or ize d copy in g and dis trib utio n is a violation of law.
Page 2
Important Safety Notice
Special components are used in this television set which are important for safety. These parts are identified on the
schematic diagram by the symboland printed in BOLD TYPE on the replacement part list. It is essential 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 receiver whose chassis 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 protect the receiver from
being damaged by accidental 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.)
Alwaysreplaceprotectivedevices,suchas
fishpaper, isolation resistors and capacitors, and
shields afterservicing thereceiver. Useonly
manufacturer’s recommended rating for fuses, circuits
breakers, etc.
High potentials are present when this receiver is
operating. Operation of the receiver without the rear
cover introduces danger for electrical shock. Servicing
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 ha ndling the
picture tube. Rough handling may cause it to implode
due to atmospheric pressure. (14.7 lbs per sq. in.). Do
not nick or scratch the glass or subject it to any undue
pressure. When handling, use safety goggles and
heavy gloves for protection. Discharge the picturetube by shorting the anode to chassis ground (not to
the cabinet or to other mounting hardware). When
discharging connect cold 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 servicing the chassis
at the bench should incorporate safety glass and
magnetic shielding. The safety glass provide shielding
for the tube viewing area against x-ray radiation as well
as implosion. The magnetic shield limits the x-ray
radiation around the bell of the picture 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 50kV without causing x-ray
radiation.
Before returning a serviced Receiver to the owner,
the service technician 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 p arallel 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 current tester (such a Simpson model
229, Sencore Model PR57 or equivalent) may be used
in the above procedure, in which case any current
measure must not exceed 0.5 milliamp. If any
measurement is out of the specified limits, there is a
possibility of a shock hazard and the receiver must be
repaired and rechecked before it is returned to the
customer.
Figure 1. Hot Check Circuit
X-ray Radiation
WARNING: The potential source of x-ray radiation in the
receiver is in the High Voltage section and the picture
tube. Refer to “X-ray Protection Circuit Check &
Adjustments” on page 5 to confirm HHS voltage.
High Voltage (CRT Anode)
Set the brightness, picture, sharpness and color
controls to minimum (to obtain dark image). Measure
the High V oltage. The high voltage should be
29.25kV ± 1.25kV. If the upper limit is out of tolerance,
immediate service and correction is required.
Note:It is important to use an accurate, calibrated
high voltage meter.
-2-
Page 3
ImportantSafetyNotice .................. 2
SafetyPrecautions................. 2
ServiceNotes........................... 4
X-Ray Protection Circuit Check
&Adjustments................. 5
ReceiversFeatureTable.................. 6
LocationofReceiverControls............. 7
Chassisview........................... 8
PartsList .............................. 9
SchematicNotes....................... 14
A-Boardschematic..................... 16
A-BoardICvoltages .................... 21
A&C-Boardlayout..................... 22
C-Boardschematic..................... 24
A&C-transistorvoltages................ 27
A-Boardwaveforms..................... 27
-3-
Page 4
Service Notes
Note:Some components may be affixed with glue. Be careful not to break or damage 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 track spacing. There are no holes in
the board to mount standard transistors or diodes.
Some chips capacitor or resistor board solder pads
may have holes through 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 component
indicates the general range of the capacitance.
Chip transistors are identified by a two letter code. The
first letter indicates the type and the second letter, the
grade of transistor.
Chip diodes have a two letter identification code as per
the code chart and 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 solder from component
end caps or terminal.
2. Without pulling up, carefully twist the component
with tweezers to break the adhesive.
3. Donotreuseremovedleadlessorchip
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 apply heat for more than
3 seconds.
Chip Components
How to Replace Flat-IC
- Required Tools -
• Soldering iron• De-solder braids
• Needle nose pliers• Magnifier
• Wire cutters (sharp & small)
1. Cut the pins of a defective IC with wire cutters.
Remove IC from board. If IC is glued to the board,
heat the IC and release the IC. See Note above.
Flat IC
2. Using soldering iron and needle nose pliers
remove the IC pins from the board.
Soldering
Iron
3. Using de-soldering braid and soldering iron remove
solder from affected are on board (pads).
De-soldering
Braid
Soldering
Iron
4. Position the new flat-ic in place (apply the pins of
the flat-ic to the soldering pads where the pins
need to be soldered). Determine the positions of
the soldering pads and pins by correctly aligning
the polarity symbol. Solder pin #1 first, align the IC.
Polarity
symbol
Solder the pin opposite to pin #1. This will assist
positioning the IC.
5. Solder all pins to the soldering pads using a fine
tipped soldering iron.
2nd solder
1st solder
Solder
6. Check with a magnifier for solder bridge between
the pins or for dry joint between pins and soldering
pads. To remove a solder bridge, use a de-solder
braid as shown in the figure below.
-4-
Soldering
Iron
Page 5
IMPORTANT: To protect against possible damage to
the solid state devices due to arcing or static discharge,
make certain that all ground wires and CRT 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 ( ) or
() 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 symbolon the schematic
must be replaced with identical parts. Order parts from
the manufacturer’s parts center using the parts
numbers shown in this service manual, or provide the
chassis number and the part reference number.
For optimum performance and reliability, all other parts
should be replaced with components of identical
specification.
X-ray Protection Circuit Check &
Adjustments
This test must be performed as final check before the
receiver is returned to the customer. If voltages are out
of tolerance, immediate service and correction is
required to insure safe operation and to prevent the
possibility of premature component failure.
Equipment:
1. Isolation transformer.
2. High voltage meter.
3. Short jumper.
4. Jumper diode (same as D823, PN S3L60P154004).
diode should be rated a minimum of 150V.
Procedure:
1. Connect the receiver to an isolation transformer.
turn receiver ON.
2. Apply a monoscope pattern.
3. In service mode (see service mode section in this
manual) select register C0B.
4. Measure TP5 (located near the tuner). Compare
the measured value to the left column of the table
below. Set C0B with value from the right column
corresponding to the measured level at TP5.
Example, if the measured level at TP5 is 1.03V, set
C0B to 03.
TP5 MEASUREMENTSET C0B TO (HEX)
0 ~ 0.93V00
0.93 ~ 0.97V01
0.97 ~ 1.01V02
1.01 ~ 1.05V03
1.05 ~ 1.09V04
1.09 ~ 1.13V05
1.13 ~ 1.17V06
1.17 ~ 1.21V07
5. Exit service mode and shut the TV OFF.
6. Connect the short jumper between TPD16 and
TPD17.
7. Connect the jumper diode between TPD14 and
TPD15 (cathode connected to TPD14, anode
connected to TPD15, see Fig. 3 for locations).
8. Apply 75VAC to the input of the isolation
transformer.
9. Turn receiver ON.
10. Set PICTURE and BRIGHTNESS to minimum.
11. Slowly increase the voltage at the input of the
isolation transformer and confirm HHS voltage
measure 35.0KV when the receiver starts to go out
of sync.
12. Turn receiver OFF and remove jumper & diode.
-5-
Page 6
Receiver Feature Table
FEA TURE / MODELALL MODELS
ChassisJP363
No. of channels181
Menu languageEng/Span/Fr
Closed CaptionX
V-Chip (USA/CANADA)X
75 Ω inputX
Remote model numberEUR501450
Picture tubeM68LGL061X
Panablack tubeX
Comb filter2Dig
V/A normV
MTS/SAP/DBXX
AI SoundX
Built-in audio power1.5W x 2 (10%)
Number of speakers2
A/V in (rear/front)1(1/1)
S-VHS input (rear/front)1/0
Headphone jackX
Dimensionsmm
(WxDxH)in
Weight (kg/lbs)35 / 77.2
Power source (V/Hz)120 / 60
Anode voltage29.25kV ±1.25kV
Video input jack
Audio input jack500mV RMS 47kΩ
A-Board TNP2AH040BH*
C-Board TNP2AA106AG*
665.2 x 545 x 594.8
26.2 x 21.5 x 23.4
75Ω, phono jack
1V
p-p
Table 1. Receiver Features
Specifications are subject to change without notice or obligation.
Dimensions and weights are approximate.
*Note:When ordering a replacement board assembly,
append an “S” next to the board number.
Example: to order the A-Board for CT-27G7DF, the
replacement board is
TNP2AH040BHS
.
-6-
Page 7
Location of Receiver Controls
Remote control
sensor
1
32
45
Figure 2. Location of controls
Quick reference control operation
1
Power button - Press to turn ON or OFF.
Volume buttons - Press to adjust sound level, or to adjust audio menus, video menus,
2
and select operating features when menus are displayed
Channel buttons - Press to select programmed channels. Press to highlight desired
features when menus are displayed. Also use to select cable converter box channels
3
after programming remote control infra-red codes (the TV/AUX/CABLE switch must be
set in CABLE position).
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 video input.
M016TQB2AA0431MANUAL, OWNERS
M0017EUR501450REMOTE CONTROL
M0018UR50EC1190ABATTERY COVER, REMOTE CONTROL
PARTS LIST
022-02
-13-
Parts List
Page 14
Schematic Notes
IMPORTANT SAFETY NOTICE
THIS S CHEMATIC DIAGRAM INCORPORATES SPECIAL
FEATURES THAT ARE IMPORTANT FOR PROTECTION FROM
X-RADIATION, FIRE AND ELECTRICAL SHOCK HAZARDS.
WHENSERVICINGIT ISESSENTIALTHAT ONLY
MANUFACTURERS SPECIFIED PARTS BE USED FOR THE
CRITICAL COMPONENTS DESIGNATED WITH AIN THE
SCHEMATIC.
SCHEMATIC NOTES
1. Resistors are carbon 1/4W unless noted
otherwise.
2. Capacitors are ceramic 50V unless noted
otherwise.
3. Coil value notes is inductance in µH.
4. Tes t point indicat ed by; Test point but no
pin .
5. Components indicated withare critical
parts and replacement should be made
with manufacture specified replacement
parts only.
6.(BOLD LINE) indicates t he route
of B+ supply.
7. The schematic diagrams are current at
the time of printing and are subject to
change without notice.
-AC input t o t he Receiver is 120V.
NTSC (HD, 1125i & 525P when
applicable)signalgeneratoris
connected to the antenna of the
Receiver. (Color bar pattern of 100
IRE white and 7.5 IRE black.)
-All Picture and Audio adjustments are
set to Normalize.
TV ANT/CABLE - (Set-Up Menu) in
TV/ANT Mode
Volume - Min.
TV/Video SW - TV position
Audio Mode - Stereo
-Voltage readings are nominal a nd
may vary ±10% on active devices.
Some voltage reading will vary
with signal strength and picture
content.
-Supply voltages are nominal.
2. Ground symbolindicates ground lead
connection of meter.
Incorrect ground connection will result
in erroneous readings.
CAUTION: Incorrect ground connection
of the test equipment will result in
erroneous readings.
CHIP TRANSISTOR
LEAD DESIGNATION
B
E
used for engineering design
purposes.
C
3
1.indicates waveformmeasurement.
(Measurement can be taken at the best
accessible location in c ommon to the
indicated point.)
2. Tak en with an NTSC signal generator
connected to the antenna terminal.
(NTSC c olor bar pattern of 8 bars of EIA
colors, 100 IRE white and 7.5 IRE black.)
3. Customer Controls (Picture/Audio Menu) are
set to Normalize. Volume is set to “MIN”.
WAVEFORM MEASUREMENTS
4. All video and color waveforms are taken
with a wideband scope and a probe
with low capacitance (10 to 1). Shape
andpeakaltitudesmayvary
depending on the type of Oscilloscope
used and its settings.
5. Ground symbolshown on waveform
number indicates (Hot) ground lead
connection of the Oscilloscope.
CAUTION: Incorrect ground connection of
the test equipment will result in erroneous
readings.
PARTS LIST
-14-
Page 15
Schematic Notes
NOTA DE SEGURIDAD
LOSDIAGRAMASELÉCTRICOSINCLUYEN
CARACTERÍSTICAS ESPECIALES M UY IMPORTANTES
PARALAPROTECCIÓNCONTRARAYOS-X,
QUEMADURAS Y DESCARGAS ELÉCTRICAS. CUANDO
SE DE SERVICIO ES IMPORTANTE USAR PARA
REEMPLAZO DE COMPONENTES CRITICOS, SOLO
PARTES ESPECIFICADAS POR EL FABRICANTES. LOS
COMPONENTES CRITICOS ESTAN SEÑALADOS EN LOS
DIAGRAMAS POR EL SIMBOLO.
NOT AS DE LOS DIAGRAMAS
1.Las Resistencias son de Carbón de 1/4W, a
menos que se indique otra característica.
2.Los Capacitores son de Cerámica para
50V, a menos que se indique otra
característica.
3.El valor indicado de las Bobinas es la
inductancia expresada en µH.
4.Los puntos de prueba en la terminal de
algún componente son indicados por Los
puntosdepruebafueradelos
componentes se indican con .
5.Los componentes señalados con el
símbolosonconsiderados
componentes críticos y deben ser
6.(LINEA G RUESA)indicalas
7.Los diagramas eléctricos están sujetos a
8.El símboloindica que es una
NOTA: Losdemassímbolosde
IDENTIFICACIÓ NDE TERMINALES
PARATRANSISTORESEN
B
E
reemplazados sólo con las partes
especificadas por el fabricante.
líneas de alimentación de los Voltajes
B+.
cambio sin previo aviso.
conexión a Tierra Caliente y el símbolo
indica conexión a Tierra Fría.
CHIP
C
componentesincluidosson
usados con fines de diseño.
MEDICIÓN DE VOLTAJES
1.Medición de voltaje:
-El voltaje de ent rada al Receptor es de
120VdeCorriente Alterna.Un
generador de patrones con formato
NTSC se conecta a la entrada de la
antena. (Patrón de Barras de Colores
con 100 IREs para el Blanco y 7.5 IREs
para el Negro.)
-Los ajustes de los Menus Picture y
Audio se normalizan.
En el Menú Set-Up, en la opción
ANTENA, se selecciona el modo de
CABLE.
El nivel de Volumen se minimiza.
De los modos TV y Video, seleccionar el
modo TV.
Seleccionar modo Estereo del Audio.
-Las mediciones de los voltajes son
nominales y pueden variar hasta
10%encomponent esen
funcionamiento. Las lecturas de los
voltajes pueden variar por la
potencia de la señal y el contenido
de la imagen.
-Las fuentes de voltajes son
nominales.
2.El símboloindica el tipo de tierra que
se utiliza en la conexión del medidor.
PRECAUCION: SI no se utiliza la
conexión a la tierra adecuada, se
obtendrán mediciones equivocadas y
podría dañar el equipo de medición.
MEDICIÓN DE FORMAS DE ONDA
1. Un símbolocomoindicael punto para medir
una señal. (La medición puede hacerse en
el punto con mayor accesib ilidad, siempre
que sea común al indicado.)
2. Se midieron utilizando un generador con
PARTS LIST
formato NTSC conectado a la terminal de la
antena. (Patrón de 8 Bar ras de Colores
EAI, formato NTSC de 100 IREs para el
Blanco y 7.5 IREs para el Negro.)
3. Los ajustes de usuario de los Menus
PICTURE y AUDIO se normalizaron.
Posteriormente el nivel de volumen se
ajusta al mínimo.
4. Las formas de onda de Video y Color
fueron tomadas con un osciloscopio de
3
banda alta y con un punta de pru eba de
baja capacitancia (10 a 1). La forma y
amplitud de las ondas puede variar
según el t ipo de osciloscopio que se
utilice y sus caracterí sticas.
5. El símbolo de tierraque aparece j unto al
número de la forma de onda, indica que
se utiliza conexión a Tierra Caliente en
el extremo negativo de la punta de
prueba.
PRECAUCION: Si no se utiliza la conexión
a la tierra adecuada, se obtendrán
mediciones equivocadas y podría dañar el
equipo de medición.