SHARP 27KX2000 Service Manual

27K-X2000
SERVICE MANUAL
S68S727K-X200
COLOR TELEVISION
Chassis No.SN-84
MODEL
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.
27K-X2000
CONTENTS
Page
» ELECTRICAL SPECIFICATIONS......................................................................................................... 1
» LOCATION OF USER'S CONTROL.....................................................................................................4
» INSTALLATION AND SERVICE INSTRUCTIONS ............................................................................... 5
» CHASSIS LAYOUT ............................................................................................................................ 13
» BLOCK DIAGRAM ............................................................................................................................. 15
» SCHEMATIC DIAGRAMS .................................................................................................................. 17
» PRINTED WIRING BOARD ASSEMBLIES........................................................................................27
» REPLACEMENT PARTS LIST ........................................................................................................... 36
» PACKING OF THE SET ..................................................................................................................... 49
ELECTRICAL SPECIFICATIONS
POWER INPUT ................................................... 120 V AC 60 Hz
POWER RATING..................................................................135 W
PICTURE SIZE ........................................... 2,187cm2 (339sq inch)
CONVERGENCE............................................................. Magnetic
SWEEP DEFLECTION .....................................................Magnetic
FOCUS ............................................... Hi-Bi-Potential Electrostatic
INTERMEDIATE FREQUENCIES
Picture IF Carrier Frequency ..................................... 45.75 MHz
Sound IF Carrier Frequency ...................................... 41.25 MHz
Color Sub-Carrier Frequency..................................... 42.17 MHz
(Nominal)
AUDIO POWER
OUTPUT RATING.............. 1.3W + 1.3W (at 10% distortion and
Dual CH Operate)
SPEAKER
SIZE ...................................................................... 8 cm (Round)
VOICE COIL IMPEDANCE............................... 8 ohm at 400 Hz
ANTENNA INPUT IMPEDANCE
VHF/UHF .................................................... 75 ohm Unbalanced
TUNING RANGES
VHF-Channels .............................................................. 2 thru 13
UHF-Channels ............................................................14 thru 69
CATV Channels ..........................................................1 thru 125
(EIA, Channel Plan U.S.A.)
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.
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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
2 2
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.
1.5k ohm 10W
0.15µF
TEST PROBE
TO EXPOSED
METAL PARTS
234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121
CONNECT TO KNOWN EARTH GROUND
SAFETY NOTICE
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.
234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121
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.
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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.
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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.
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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.
S01 PICTURE HEIGHT 0 ~ 127 71 RF signal input (TUNER-B) Deflection processor IC (IC502) adjusted
S02 V-LINEARITY 0 ~ 31 27 ” S03 V-CORRECTION 0 ~ 63 40 40 ” S04 PICTURE WIDTH 0 ~ 63 50 45 ” S05 E-W PARABOLA 0 ~ 63 15 32 ” S06 E-W CORNER 0 ~ 31 13 16 ” S07 TRAPEZIUM 0 ~ 127 65 64 ” S08 AGC SW 0 ~ 1 1 1 ” S09 S10 TINT 0 ~ 63 20 ” S11 COLOR(SUB COLOR) 0 ~ 31 13 ” S12 BRIGHT S13 SHARP(SHARPNESS) 0 ~ 27 5 0 ” S14 V-POSITION 0 ~ 7 0 0 ” S15 H-POSITION 0 ~ 31 17 ” S16 R CUT-OFF 0 ~ 255 64 ” S17 G CUT-OFF 0 ~ 255 64 ” S18 B CUT-OFF 0 ~ 255 64 ” S19 G(R) DRIVE 0 ~ 127 64 ” S20 B DRIVE 0 ~ 127 64 ” S21 Y-MUTE/V-OFF 0 ~ 2 0 ” S22 Y-γ CURVE 0 ~ 3 0 3 VCJ IC (IC401) adjusted S23 VSM PHASE 0 ~ 3 1 3 ” S24 APACON PEAK f0 0 ~ 7 1 1 ” S25 DC RESTORATION 0 ~ 63 21 21 ” S26 S27 S28 APL VS BPS 0 ~ 3 1 1 ” S29 B.L.C. 0 ~ 1 1 1 ” S30 DYNAMIC ABL POINT 0 ~ 7 4 0 ” S31 DYNAMIC ABL GAIN 0 ~ 7 4 7 ” S32 ABL POINT 0 ~ 7 3 3 ” S33 ABL GAIN 0 ~ 7 3 2 ” S34 Y-DL 0 ~ 1 1 0 ” S35 TOF-f0 0 ~ 7 4 7 ” S36 TOF-Q 0 ~ 7 4 4 ” S37 VSM GAIN 0 ~ 3 1 3 ” S38 OSD SL 0 ~ 1 0 1
ADJUSTMENT ITEM
PICTURE(SUB CONTRAST)
(BRIGHTNESS)
DC RESTORATION LIMIT BLACK STRETCH POINT
VARIABLE
DATA RANG
0 ~ 31 28 VCJ IC (IC401) adjusted
0 ~ 101 58
0 ~ 3 0 3 ” 0 ~ 7 3 3
INITIAL
VALUE
FIXED
VALUE
INPUT CONDITIONS
(or EXT. Video input)
CONTROL DESTINATION
00: Normal, 01: Y-mute, 03: Horizontal Y-mute
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27K-X2000
SERVICE
No. S39 C-DECODE 0 ~ 255 105 161 ” S40 OSD POSITION 0 ~ 15 11 C.C. display positioning M01 INPUT LEVEL (ATT) 0 ~ 15 7 MTS IC (IC3001) adjusted M02 MTS VCO 0 ~ 63 37 ” M03 FILTER 0 ~ 63 30 ” M04 WIDE BAND 0 ~ 63 17 ” M05 SPECTRAL 0 ~ 63 22 ” M06 MTS DATA READ 0 ~ 1 0 Note 1 ” Factory-adjusted only P01 P02 PIP TINT (TINT) 0 ~ 63 41 37 ” P03 P04 Y-OFFSET(Y_OFFSET) 0 ~ 31 9 09 ” P05 PIP H-POSI(HXA) 0 ~ 255 9 10 ” P06 BGP(HADJ) 0 ~ 15 0 00 ” P07 C01 C02 TINT-C 0 ~ 63 20 14 ” C03 C04 C05 C06 V-POSITION-C 0 ~ 7 0 0 ” C07 H-POSITION-C 0 ~ 31 19 ” C08 R CUT-OFF-C 0 ~ 255 64 ” C09 G CUT-OFF-C 0 ~ 255 64 ” C10 B CUT-OFF-C 0 ~ 255 64 ” C11 G(R) DRIVE-C 0 ~ 127 64 ” C12 B DRIVE-C 0 ~ 127 64 ” C13 VSM GAIN-C 0 ~ 3 2 3 ” A01 PICTURE-2 0 ~ 31 28 RF signal input (TUNER-A) ” A02 TINT-2 0 ~ 63 20 ” A03 INPUT LEVEL-2 0 ~ 15 7 MTS IC (IC3001) adjusted A04 WIDE BAND-2 0 ~ 63 17 ” A05 SPECTRAL-2 0 ~ 63 22
ADJUSTMENT ITEM
PIP Y-LEVEL(CONTRAST)
PIP COLOR(COLOR_SAT)
FREE RUN(FREE_RUN_ADJ)
PICTURE-C(SUB CONTRAST)
COLOR-C(SUB COLOR) BRIGHT-C(BRIGHTNESS) SHARP-C(SHARPNESS)
VARIABLE
DATA RANG
0 ~ 127 43 P-IN-P adjusted
0 ~ 127 55 RF signal input (TUNER-B) P-IN-P adjusted
0 ~ 15 11 11 ” 0 ~ 31 28 14 Component signal input VCJ IC (IC401) adjusted
0 ~ 63 13 3 ” 0 ~ 101 58 ” 0 ~ 27 5 0
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
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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).
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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.
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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 Figure B 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.
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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".
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