In the interests of user-safety (Required by safety regulations in some countries) the set should be restored to its
original condition and only parts identical to those specified should be used.
Specifications are subject to change without
prior notice.
SHARP CORPORATION
This document has been published to be used for after
sales service only.
The contents are subject to change without notice.
1
27K-X2000
IMPORTANT SERVICE SAFETY PRECAUTION
Service work should be performed only by qualified service technicians who are thoroughly
familiar with all safety checks and the servicing guidelines which follow:
WARNING
1. For continued safety, no modification of any circuit
should be attempted.
2. Disconnect AC power before servicing.
3. Semiconductor heat sinks are potential shock
hazards when the chassis is operating.
4. The chassis in this receiver has two ground systems
which are separated by insulating material. The nonisolated (hot) ground system is for the B+ voltage
regulator circuit and the horizontal output circuit. The
isolated ground system is for the low B+ DC voltages
and the secondary circuit of the high voltage
transformer.
To prevent electrical shock use an isolation
transformer between the line cord and power
receptacle, when servicing this chassis.
CAUTION: FOR CONTINUED
PROTECTION AGAINST A
RISK OF FIRE, REPLACE
4A 125V
ONLY WITH SAME TYPE 4A125V FUSE.
SERVICING OF HIGH VOLTAGE SYSTEM
AND PICTURE TUBE
When servicing the high voltage system,
remove the static charge by connecting a
10k ohm resistor in series with an insulated
wire (such as a test probe) between the picture tube ground and the anode lead. (AC
line cord should be disconnected from AC
outlet.)
1. Picture tube in this receiver employs integral
implosion protection.
2. Replace with tube of the same type number for
continued safety .
3. Do not lift picture tube by the neck.
4. Handle the picture tube only when wearing
shatterproof goggles and after discharging the high
voltage anode completely.
X-RADIATION AND HIGH VOLTAGE LIMITS
1. Be sure all service personnel are aware of the
procedures and instructions covering X-radiation. The
only potential source of X-ray in current solid state
TV receivers is the picture tube. However, the picture
tube does not emit measurable X-Ray radiation, if
the high voltage is as specified in the "High Voltage
Check" instructions.
It is only when high voltage is excessive that Xradiation is capable of penetrating the shell of the
picture tube including the lead in the glass material.
The important precaution is to keep the high voltage
below the maximum level specified.
2. It is essential that servicemen have available at all
times an accurate high voltage meter.
The calibration of this meter should be checked
periodically.
3. High voltage should always be kept at the rated value
−no higher. Operation at higher voltages may cause
a failure of the picture tube or high voltage circuitry
and;also, under certain conditions, may produce
radiation in exceeding of desirable levels.
4. When the high voltage regulator is operating properly
there is no possibility of an X-radiation problem. Every
time a colour chassis is serviced, the brightness
should be tested while monitoring the high voltage
with a meter to be certain that the high voltage does
not exceed the specified value and that it is regulating
correctly .
5. Do not use a picture tube other than that specified or
make unrecommended circuit modifications to the
high voltage circuitry.
6. When trouble shooting and taking test measurements
on a receiver with excessive high voltage, avoid being
unnecessarily close to the receiver.
Do not operate the receiver longer than is necessary
to locate the cause of excessive voltage.
2
22
IMPORTANT SERVICE SAFETY PRECAUTION
(Continued)
27K-X2000
BEFORE RETURNING THE RECEIVER
(Fire & Shock Hazard)
Before returning the receiver to the user, perform
the following safety checks.
1. Inspect all lead dress to make certain that leads are
not pinched or that hardware is not lodged between
the chassis and other metal parts in the receiver.
2. Inspect all protective devices such as non-metallic
control knobs, insulating materials, cabinet backs,
adjustment and compartment covers or shields,
isolation resistor-capacity networks, mechanical
insulators, etc.
3. To be sure that no shock hazard exists, check for
leakage current in the following manner.
» Plug the AC cord directly into a 120 volt AC outlet,
(Do not use an isolation transformer for this test).
» Using two clip leads, connect a 1.5k ohm, 10 watt
resistor paralleled by a 0.15µF capacitor in series with
all exposed metal cabinet parts and a known earth
ground, such as electrical conduit or electrical ground
connected to earth ground.
» Use an AC voltmeter having with 5000 ohm per volt,
or higher, sensitivity to measure the AC voltage drop
across the resistor.
» Connect the resistor connection to all exposed metal
parts having a return to the chassis (antenna, metal
cabinet, screw heads, knobs and control shafts,
escutcheon, etc.) and measure the AC voltage drop
across the resistor.
AII checks must be repeated with the AC ine cord
plug connection reversed. (If necessary, a nonpolarized adapter plug must be used only for the
purpose of completing these check.)
Any current measured must not exceed 0.5 milliamp.
Any measurements not within the limits outlined
above indicate of a potential shock hazard and
corrective action must be taken before returning the
instrument to the customer.
Many electrical and mechanical parts in television
receivers have special safety-related characteristics.
These characteristics are often not evident from visual
inspection, nor can protection afforded by them be
necessarily increased by using replacement components
rated for higher voltage, wattage, etc.
Replacement parts which have these special safety
characteristics are identified in this manual; electrical
components having such features are identified by "å"
and shaded areas in the Replacement Parts Lists and
Schematic Diagrams.
For continued protection, replacement parts must be
identical to those used in the original circuit. The use of
substitute replacement parts which do not have the same
safety characteristics as the factory recommended
replacement parts shown in this service manual, may
create shock, fire, X-radiation or other hazards.
3
27K-X2000
LOCATION OF USER'S CONTROL
4
27K-X2000
INSTALLATION AND SERVICE INSTRUCTIONS
Note:(1)When performing any adjustments to resistor controls and transformers use non-metallic
screwdrivers or TV alignment tools.
(2)Before performing adjustments, the TV set must be on at least 15 minutes.
CIRCUIT PROTECTION
The receiver is protected by a 4.0A fuse
(F701), mounted on PWB-A, wired into one
side of the AC line input.
X-RADIATION PROTECTOR CIRCUIT TEST
After service has been performed on the horizontal
deflection system, high voltage system, B+ system,
test the X-Radiation protection circuit to ascertain
proper operation as follows:
1) Apply 120V AC using a variac transformer for
accurate input voltage.
2) Allow for warm up and adjust all customer controls
for normal picture and sound.
3) Receive a good local channel.
4) Connect a digital voltmeter to TP653 and make sure
that the voltmeter reads 8.9V ±0.5V.
5) Apply external 10.9V DC at TP653 by using an
external DC supply, TV must be shut off.
6) T o reset the protector , unplug the AC cord. Now make
sure that normal picture appears on the screen.
7) If the operation of the horizontal oscillator does not
stop in step 5, the circuit must be repaired before the
set is returned to the customer.
HIGH VOLTAGE CHECK
High voltage is not adjustable but must be checked
to verify that the receiver is operating within safe
and efficient design limitations as specified checks
should be as follows:
1. Connect an accurate high voltage meter between
ground and anode of picture tube.
2. Operate receiver for at least 15 minutes at 120V AC
line voltage, with a strong air signal or a properly tuned
in test signal.
3. Enter the service mode and select the service
adjustment "S21" and Bus data "01" (Y-mute on).
4. The voltage should be approximately, 28.1kV (at zero
beam).
If a correct reading cannot be obtained, check circuitry
for malfunctioning components. After the voltage test,
make Y-mute off to the normal mode.
5
27K-X2000
For adjustments of this model, the bus data is converted to various analog signals by the D/A converter
circuit.
Note: There are still a few analog adjustments in this series such as focus and master screen voltage.
Follow the steps below whenever the service adjustment is required. See "Table-B" to determine, if service adjustments are required.
1. Service mode
Before putting unit into the service mode, check that
customer adjustments are in the normal mode. Use
the reset function in the video adjustment menu to
ensure customer controls are in their proper (reset)
position.
2. Service number selection
Once in the service mode, press the Ch-up or Chdown button on the remote controller or at the set.
The service adjustment number will vary in
increments of one, from "S01" to "A05". Select the
item you wish to adjust.
3. Data number selection
Press the Vol-up or down button to adjust the data
number.
SERVICE ADJUSTMENT NUMBER
To enter the service mode and exit service mode.
While pressing the Vol-up and Ch-up buttons at the
sametime, plug the AC cord into a wall socket.
Now the TV set is switched on and enters the service
mode.
To exit the service mode, turn the television off by
pressing the power button.
DATA NUMBER
CHANNEL
(INPUT)
S01 081
2
ANT-B
S01 D:00
Figure A.
6
27K-X2000
» To call up the service mode, hold down the CH UP and VOL UP keys of the unit at once and plug the AC power
cord into a wall outlet. The unit switches on and comes in the service mode.
» Now hold down both the CH UP and CH DOWN keys of the unit for 2 seconds or longer. The above default values
are written in the EEPROM.
SERVICE
No.
S01PICTURE HEIGHT0 ~ 12771RF signal input (TUNER-B)Deflection processor IC (IC502) adjusted
0 ~ 151111 ” ”
0 ~ 312814Component signal inputVCJ IC (IC401) adjusted
0 ~ 63133 ” ”
0 ~ 10158 ” ”
0 ~ 2750 ” ”
INITIAL
VALUE
FIXED
VALUE
INPUT CONDITIONS
CONTROL DESTINATION
Note 1 : This item is used only at the manufacturing factory.
Do not change the data. (If this setting is changed to "1", the adjustment data may get wrong.)
Table - A
8
27K-X2000
Holding down both the CH-up/down buttons on the TV set at service mode for more than 2 seconds will automatically
write the above initial values into IC2002.
PART REPLACED
IC2001
IC401
IC2002
CRT
IC3001
IC1801
ADJUSTMENT
NECESSARY
X
X
X
X
X
UNNECESSARY
X
Table - B
NOTES
Data is stored in IC2002.
The adjustment is needed to compensate for characteristics
of parts including IC401.
Holding down both the CH-up/down bottons on the TV set in
the service mode for more than 2 seconds will automatically
write the above initial values into IC2002. Then perform a
complete adjustment.
Adjust items related to picture tube only.
Adjust items related to MTS only (M01~M05).
Adjust items related to P-IN-P only (P01~P07).
9
27K-X2000
SERVICE ADJUSTMENT
Entering The Fixed Values
1. Before starting all the adjustments, enter the fixed
values listed in Table - A.
Screen Adjustment
1. Feed the B/W pattern signal from the signal generator.
2. Connect the oscilloscope probe between TP854 and
GND.
3. Set the S21 bus data to "01" to get the Y signal mute.
4. Adjust the S16(R), S17(G) and S18(B) settings to
Step "64".
5. Adjust the S12 (SUB-BRIGHT) setting to fix the
voltage between TP854 and GND at 2.15V.
6. Adjust the SCREEN control until the raster becomes
as dim as possible and just visible.
7. Select a luminance-short gun, and adjust the bus data
of S16(R), S17(G) or S18(B) to have the luminance
at the white level.
8. Adjust the SCREEN control again to cut off the CRT.
9. Set the S21 bus data to "00" to deactivate the Y signal
mute.
Sub-Picture Adjustment
1. Receive a good local channel signal through the
antenna B.
2. Make sure the customer picture control is set to
maximum.
3. Enter the service mode and select the service
adjustment "S09".
4. Adjust the data value to achieve normal contrast
range.
5. Receive the same local channel through the antenna
A.
6. Adjust the "A01" setting to achieve the same contrast
as that with the antenna B.
Sub-Tint Adjustment
1. Receive a good local channel through the antenna
B.
2. Set customer tint control to center of it's range.
3. Enter the service mode and select the service
adjustment "S10".
4. Adjust "S10" data value to obtain normal flesh tones.
5. Receive the same local channel through the antenna
A.
6. Adjust the "A02" setting to achieve the same tint as
that with the antenna B.
2.15 ± 0.15 V
DC
GND
White Balance Adjustment
White balance adjustment of composite signal input
1. Feed the B/W pattern signal via the video input
terminal from the signal generator.
2. Adjust the "S19" and "S20" settings to obtain the
specified white level.
White balance adjustment of component signal input
1. Feed the B/W pattern signal via the component signal
input Y terminal from the signal generator.
2. Set the S21 bus data to "01" to get the Y signal mute.
3. Adjust the C08(R), C09(G) and C10(B) settings to
step "64".
4. Select a luminance-short gun, and adjust the bus data
of C08(R), C09(G) or C10(B) to have the luminance
at the white level.
5. Adjust the "C11" and "12" settings to obtain the
specified white level.
Sub-Color Adjustment
1. Receive a good local channel.
2. Make sure the customer color control is set to center
position .
3. Enter the service mode and select service adjustment
"S1 1".
4. Adjust "S11" data value to obtain normal color level.
10
27K-X2000
Sub-Brightness Adjustment
1. Have unit receive a good local channel.
2. Make sure the customer brightness control is set to
center position.
3. Enter the service mode and select the service
adjustment "S12".
4. Adjust "S12" data value to obtain normal brightness
level.
5. Enter the same data value as the "S12" setting to
"C04".
Vertical Linearity Adjustment
1. Feed the circular or crosshatch pattern signal.
2. Enter the service mode and select the service
adjustment "S02".
3. While observing the top and bottom of the screen,
adjust "S02" data value to proper vertical linearity.
Vertical Size Adjustment
1. Feed the circular or crosshatch pattern signal.
2. Enter the service mode and select the service
adjustment "S01".
3. While observing the top and bottom of the screen,
adjust "S01" data value to proper vertical size.
Horizontal Position Adjustment
1. Have unit receive a good local channel.
2. Enter the service mode and select the service
adjustment "S15".
3. Adjust "S15" data value so that picture is centered.
4. Enter the "S15" setting plus 2 steps to "C07".
Caption Position Adjustment (Horizontal)
1. Have unit receive a good local channel.
2. Enter the service mode and select the service
adjustment "S40".
3. A black text box appears on the screen. (see FigureB below)
4. Adjust "S40" data value so that text box is positioned
in the center of the screen.
Vertical Phase Adjustment
1. Enter the service mode and select the service
adjustment "S14".
2. Adjust data value to "00".
Note: This must be set "00" when changed data retrace
line will appear.
Figure B.
11
27K-X2000
P-IN-P ADJUSTMENTMTS ADJUSTMENT
MTS Level Adjustment
1. Feed the following monaural signal to pin (14) of
IC3001.
Monaural signal : 300Hz, 245mVrms
2. Connect the rms voltmeter to pin (39) of IC3001.
3. Enter the service mode and select the service
adjustment "M01".
4. Adjust the data so that the rms voltmeter reads.
Spec.: 490 ±10mVrms.
MTS VCO Adjustment
1. Keep the unit in no-signal state.
2. Connect the frequency counter to pin (39) of IC3001.
3. Connect a capacitor (100µF, 50V) in between
positive(+) side of C3005 and ground.
4. Enter the service mode and select the service
adjustment "M02"
5. Adjust the data so that the frequency counter reads.
Spec.: 62.94 ±0.75kHz.
Filter Adjustment
1. Feed the following stereo pilot signal to pin (14) of
IC3001 .
Stereo pilot signal: 9.4kHz, 600mVrms.
2. Enter the service mode and select the service
adjustment "M03".
3. Adjust the data at the point where "OK" appears on
the screen. The "OK" represents the approximate
center of the adjustable range of the data.
Separation Adjustment
1. Connect the rms voltmeter to pin (39) of IC3001.
2. Receive the following composite stereo signal 1.
Composite stereo signal: 30% modulation, left
channel only, noise reduction on, 300Hz
3. Enter the service mode and select the service
adjustment "M04".
4. Adjust the data until the AC voltage reading of the
rms voltmeter is minimum.
5. Receive the following composite stereo signal 2.
Stereo signal: 30% modulation, left channel only,
noise reduction on, 3kHz
6. Enter the service mode and select the service
adjustment "M05".
7. Adjust the data until the AC voltage reading of the
rms voltmeter is minimum.
8. Take the above steps 1 thru 8 again for fine
adjustment.
P-IN-P Y LEVEL Adjustment
1. Receive a good local channel.
2. Enter the service mode and select the service
adjustment "P01".
3. Adjust "P01" data value to obtain normal contrast
level.
P-IN-P TINT Adjustment
1. Receive a good local channel.
2. Enter the service mode and select the service
adjustment "P02".
3. Adjust data value to "37".
P-IN-P COLOR Adjustment
1. Receive a good local channel.
2. Make sure the customer color control is set to center
position.
3. Enter the service mode and select service adjustment
"P03".
4. Adjust "P03" data value to obtain normal color level.
P-IN-P Y -OFF SET Adjustment
1. Receive a good local channel.
2. Enter the service mode and select the service
adjustment "P04".
3. Adjust data value to "09".
P-IN-P H-POSITION Adjustment
1. Receive a good local channel.
2. Enter the service mode and select the service
adjustment "P05".
3. Adjust data value to "10".
P-IN-P BURST GATE PULSE (for MAIN)
1. Receive a good local channel.
2. Enter the service mode and select the service
adjustment "P06".
3. Adjust data value to "00".
P-IN-P FREE RUN
1. Recieve a good local channel.
2. Enter the service mode and select service adjustment
"P07".
3. Adjust data value to "11".
12
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