This simplified service manual is issued to add listed models CT-27SX12F/UF and CT-27SX32F/UF to the main
service manual order No. MTNC010527C1 (CT-27SX31E) and CT-24SX12F/UF models to simplified service manual
order number MTNC010837A1 (CT-24SX11E). A set of unique schematics, unique settings and a complete parts list
are included in this manual.
Please file and use this simplified service manual together with main service manual, order No. MTNC010527C1
(CT-27SX31E) and simplified service manual order number MTNC010837A1 (CT-24SX11E).
“WARNING! This Service Manualisdesigned for experienced repair technicians only and is not designed for useby 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 serviced or repaired only by experienced professional technicians. Any attempt to
service or repair the product or products dealt with in this Service Manual by anyone else could result in seriousinjury or death.”
Chassis
The service technician is requiredtoreadand follow the “Safety Precautions”and“Important Safety Notice” in the Main Manual.
Copyright2002by 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 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.)
Always Replace Protective Devices,suchas
fishpaper, isolation resistors and capacitors, and
shields after servicing theReceiver. Use only
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 Handling 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
capableofhandling50kVwithoutcausing
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 p ath 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 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.
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 High Voltagesection and the picture tube.
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 should be 30.55 ± 1.25kV. 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 failure.
-2-
About lead free solder (PbF)
component
Note: Lead is listed as (Pb) in the periodic table of elements.
In the information below, Pb will refer to Lead solder, and PbF will refer to Lead Free Solder.
The Lead Free Solder used in our manufacturing process and discussed below is (Sn+Ag+Cu).
That is Tin (Sn), Silver (Ag) and (Cu) although other types are available.
This model uses Pb Free solder in it’s manufacture due to environmental conservation issues. For
service and repair work, we’d suggest the use of Pb free solder as well, although Pb solder may be
used.
PCBs manufactured using lead free solder will have the PbF within a leaf Symbolstamped on the
back of PCB.
Caution
• Pb free solder has a higher melting point than standard solder. Typically the melting
point is 50 ~ 70 °F(30~40°C) higher. Please use a high temperature soldering iron
and set it to 700 ± 20 °F(370± 10 °C).
• Pb free solder will tend to splash when heated too high (about 1100 °For600°C).
If you must use Pb solder, please completely remove a ll of the Pb free solder on the
pins or solder area before applying Pb solder. If this is not practical, be sure to heat the
Pb free solder until it melts, before applying Pb solder.
• After applying PbF solder to double layered boards, please check the component side
for excess solder which may flow onto the opposite side. (see figure below)
component
remove all of the
excess solder
pin
slice view
solder
Suggested Pb free solder
There are several kinds of Pb free solder available for purchase. This product uses Sn+Ag+Cu
(tin, silver, copper) solder. However, Sn+Cu (tin, copper), Sn+Zn+Bi (tin, zinc, bismuth) solder
canalsobeused.
0.3mm X 100g
0.6mm X 100g1.0mm X 100g
-3-
ImportantSafetyNotice...................2
SafetyPrecautions .................2
GeneralGuidelines................ 2
LeakageCurrentColdCheck .........2
X-rayRadiation....................2
About lead free solder . . . . . . . . . . . . ........3
Note:These components are affixed with glue. Be careful not to break or damage any foil under t he
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 Inst allation
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.
TYPE
b
e
ANODES
MH DIODE
Chip Components
GRADE
c
TRANSISTOR
COMMON
CATHODE
SOLDER
CAPS
CAPACITOR
1ST DIGIT
RESISTOR
SOLDER
CAPS
2ND DIGIT
MULTIPLIER
=1600 = 1.6k
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.
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.
2nd solder
Soldering
Iron
1st solder
-5-
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.
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.
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.
Board Table Description
BOARD
CT-24SX12F
CT-24SX12UF
CT-27SX12F
CT-27SX12UF
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
shouldbereplacedwithcomponentsof
identical specification.
ChassisNA8MS
No. of channels181
Menu languageENG/SPAN/FR
Closed CaptionX
V-Chip (USA/CANADA)X
Picture in Picture---X
2RF---X
75Ω inputX
Remote Model No.EUR7613Z10EUR7613Z10EUR7613Z30
Picture tubeA60LU Q085 XA68QCP893XUM68LUQ085X
Picture tube SupplierMMECSAMSUNGMDDA
Comb Filter3DIG
HEC/VECVEC
VMVM
V/A norm (X=BOTH)X
CT-27SX12F/UF
and
CT-27SX32F/UF
use different
picture tubes.
Please confirm
the model
name before
placing orders.
Color TempX
MTS/SAP/DBXX
BASS/BL/TRE ControlX
AI SoundX
SurroundX
SPATIALIZER/BBEBBE
Built-in audio power7W X 2
No. of speakers2
A/V in (rear/front)3(2/1)
S-VHS Input (rear/front)1/1
Component Input
(Y,Pb,Pr)
Audio Out
(FAO:F,VAO:V)
EPJ/HPJ/MISCHPJ
Dimensionsmm
(WxDxH)in
Weight (kg/lbs)35/77.1644.5/98.1
Power source (V/Hz)120/60
Anode voltage30.55kV ± 1.25kV
Video input jack
Audio input jack500mV RMS 47kΩ
626x596x733.5
27.1x19.8x23.8
1V
p-p
1
F, V
772x596x733.5
27.1x19.8x23.8
75Ω,phono jack
Specifications
are subject to
change
without notice
or obligation.
Dimensions
andweights
are
approximate.