1.When servicing, observe the original lead dress. If a short circuit is found, replace all parts which have been overheated or
damaged by the short circuit.
2.After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properly
installed.
3.After servicing, make the following leakage current checks to prevent the customer from being exposed to shock hazards.
1.1.1.Leakage Current Cold Check
1.Unplug the AC cord and connect a jumper between the two
prongs on the plug.
2.Measure the resistance value, with an ohmmeter, between
the jumpered AC plug and each exposed metallic cabinet
part on the equipment such as screwheads, connectors,
control shafts, etc. When the exposed metallic part has a
return path to the chassis, the reading should be between
1M9 and 5.2M9.
When the exposed metal does not have a return path to
the chassis, the reading must be
Figure 1
.
1.1.2.Leakage Current Hot Check (See
Figure 1.)
1.Plug the AC cord directly into the AC outlet. Do not use an
isolation transformer for this check.
2.Connect a 1.5k9, 10 watts resistor, in parallel with a 0.15µF
capacitors, between each exposed metallic part on the set
and a good earth ground such as a water pipe, as shown in
Figure 1.
3.Use an AC voltmeter, with 1000 ohms/volt or more
sensitivity, to measure the potential across the resistor.
4.Check each exposed metallic part, and measure the
voltage at each point.
5.Reverse the AC plug in the AC outlet and repeat each of the
above measurements.
6.The potential at any point should not exceed 0.75 volts
RMS. A leakage current tester (Simpson Model 229 or
equivalent) may be used to make the hot checks, leakage
current must not exceed 1/2 milliamp. In case a
measurement is outside of the limits specified, there is a
possibility of a shock hazard, and the equipment should be
repaired and rechecked before it is returned to the
customer.
Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called
Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field-effect transistors and
semiconductor "chip" components. The following techniques should be used to help reduce the incidence of component damage
caused by electro static discharge (ESD).
1.Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off any ESD on your
body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging ESD wrist strap,
which should be removed for potential shock reasons prior to applying power to the unit under test.
2.After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such as alminum
foil, to prevent electrostatic charge buildup or exposure of the assembly.
3.Use only a grounded-tip soldering iron to solder or unsolder ES devices.
4.Use only an anti-static solder removal device. Some solder removal devices not classified as "anti-static (ESD protected)" can
generate electrical charge sufficient to damage ES devices.
5.Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ES devices.
6.Do not remove a replacement ES device from its protective package until immediately before you are ready to install it. (Most
replacement ES devices are packaged with leads electrically shorted together by conductive foam, alminum foil or comparable
conductive material).
7.Immediately before removing the protective material from the leads of a replacement ES device, touch the protective material
to the chassis or circuit assembly into which the device will be installed.
Caution
Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.
8.Minimize bodily motions when handling unpackaged replacement ES devices. (Otherwise hamless motion such as the brushing
together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static electricity (ESD) sufficient to
damage an ES device).
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 Symbol
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 s oldering iron and set it to 700 ± 20 °F (370 ± 10 °C).
·Pb free solder will tend to splash when heated too high (about 1100 °F or 600 °C).
If you must use Pb solder, please completely remove all 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)
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 can also be used.
1.Self-Check is used to automatically check the bus lines and hexadecimal code of the TV set.
2.To get into the Self -Check mode press the [ Down (
time pressing the [ SET UP ] button on the remote control, and the screen will show :
) ] button on the customer controls at the front of the set, at the same
If the CCU ports have been checked and found to be incorrect or not located then “--” will appear in place of “O.K.”.
5SERVICE HINTS
5.1.Hotel Mode
Purpose
1.At Hotels, this Mode prevent customer from changing the TV preset data, such as Channel preset data.
Note:
This Mode is useful for hotel, you should not get into “Hotel Mode” with Normal use.
Operation
1.To get into “ Hotel Mode”, press “Recall” button on the remote control and Channel up “[
simultaneously, after setting the “Off-Timer” mode.
2.In this mode, The Channel up and down Function will be able as normal Mode, and The maximum volume level for this
mode is set at the current volume level, that means setting at the level before entering the mode. However, other function
will be disable.
3.To exit This mode, press “SET UP” button on the remote control and the “Volume Down [
simultaneously.
* This Information is informed by Service Manual only.
MPU controls the functions switching for each IICs through IIC bus in this chassis. The following setting and adjustment c an be
adjusted by remote control in Service Mode.
8.1.How to enter SERVICE 1
1.In sound menu, set BASS to MAXIMUM, and set TREBLE to MINIMUM.
2.Simultaneously press INDEX button on remote control and DOWN button [
8.2.How to enter SERVICE 2
1.Set the channel to CH99.
2.Press HOLD button on remote control.
Note:
To exit to Service mode, press N or Power button on remote control.
without sub-picture (0), with sub-picture (1)
2 tuner (1), 1 tuner (0)
enable (1)
enable (1)
16:9 (1), 4:3 (0)
ASIA / M.E. (1)
Noise mute enable(0)
Monitor out AV1 mute(1)
MACO tuner (0), ALPS tuner (1)
Power on EC enable (1)
Blanking enable (1)
Blanking enable (1)
WSS enable only in aspect Auto (0), WSS always enable (1)
TV Volume correction enable (1)
If the memory IC (IC1004) or DG Board is replaced, option code should be re-memorized.
Spare part of IC1004 is already memorized all Data for TX-15LT2M/Z.
If you use for other model, you should re-memorized the different option code in SERVICE 2 mode.
1.Connect RF signal generator to antenna terminal.
2.Receive a RF signal, Colour bar.
3.Enter service 1 mode, and select RF AGC.
4.Adjustment begins when the blue button of the remote controller is pushed.
5.It waits to become stable.
6.The STR button of the remote controller is pushed, and adjustment value is saved.
9.2.DVCO Adjustment
1.Connect PAL colour bar signal generator to AV1 (SCART) terminal.
2.Input a PAL Color bar.
3.Enter service 1 mode, and select DVCO.
4.Adjustment begins when the blue button of the remote controller is pushed.
5.It waits to become stable.
6.The STR button on remote controller is pushed, and adjustment value is saved.
22
Remarks:
1. The Power Circuit contains a circuit area which uses a separate power supply to isolate the
earth connection.
The circuit is defined by HOT and COLD indications in the schematic diagram. Take the
follwing precautions.
All circuits, except the Power Circuit, are cold.
Precautions
a. Do not touch the hot part or the hot and cold parts at the same time or you may
be shocked.
b. Do not short- circuit the hot and cold circuits or a fuse may blow and parts may
break.
c. Do not connect an instrument, such as an oscilloscope, to the hot and cold
circuits simultaneously or a fuse may blow.
Connect the earth of instruments to the earth connection of the circuit being
measured.
d. Make sure to disconnect the power plug before removing the chassis.
2. Following diodes are interchangeable.
MA150- MA162 (Replacement part)
TX-15LT2M/Q/T/X/Z
Schematic Diagram Notes
TX-15LT2M/Q/T/X/Z Power Block DiagramTX-15LT2M/Q/T/X/Z Power Block Diagram
TX-15LT2M/Q/T/X/Z Signal Block DiagramTX-15LT2M/Q/T/X/Z Signal Block Diagram
TX-15LT2M/Q/T/X/Z Signal Block DiagramTX-15LT2M/Q/T/X/Z Signal Block Diagram