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TROUBLE-SHOOTING GUIDE
1. NO POWER-1
NO POWER (POWER INDICATOR OFF)
CHECK D901 DC VOLTAGE ? (250~350V) YES
NO
TROUBLE IN F901, R902, R903, TH901, IC902, P901, POWER CORD
CHECK IC903 PIN 5 WAVEFORM ?
NO
TROUBLE IN IC903, SUB SMPS CIRCUIT
YES
CHECK C946 DC VOLTAGE ? (5.5~7V)
NO
TROUBLE IN R961, D917
YES
CHECK IC909 OUTPUT VOLTAGE ? (DC 5.0V)
NO
TROUBLE IN IC909 B+ LINE
YES
TROUBLE IN IC801 (MICOM)
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2. NO POWER-2
NO POWER (LED COLOR IS ORANGE)
CHECK H/V SYNC SIGNAL ? (IC801 PIN 29, 27 )
NO
CHECK P802-P552, P702-P303, P553-P302, SIGNAL CABLE?
NO
TROUBLE IN IC801(MICOM)
YES YES TROUBLE IN P802-P552, P702-P303, P553-P302, SIGNAL CABLE, BNC/D-SUB PCB TROUBLE IN BUTTON CONTROL PCB (KBD CIRCUIT) SEE NO.11 NO OSD CONTROL
CHECK IC801 PIN 19 VOLTAGE WHEN POWER SWITCH PRESS ? (0.25 0.25V)
NO
YES
CHECK IC801 PIN 41 ? (LOW)
NO
TROUBLE IN IC801(MICOM)
YES
TROUBLE IN MAIN SMPS (IC901, IC905, IC906, Q903, Q906, Q907, Q254)
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3. NO POWER-3
NO POWER (POWER INDICATOR IS BLINKING OR ABNORMAL, AND ACOUSTIC NOISE FROM INSIDE)
CHECK C939 DC VOLTAGE ? (175V)
NO
TROUBLE IN B+ (12V) LINE, IC905, IC907
YES
CHECK SMPS SECONDARY DIODE ? (D922~D930) YES
NO
TROUBLE IN D922~D930
CHECK Q711(H-OUT) D717 (DAMPER) Q401, D403, D404 ?
NO
TROUBLE IN Q401, Q711, D403, D404, D717
YES
CHECK SMPS SECONDARY B+ CIRCUIT ABNORMAL ?
NO
TROUBLE IN SMPS SECONDARY CIRCUIT
YES
TROUBLE IN IC901, IC902, Q903, Q907, D906
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4. NO VIDEO
NO VIDEO (RASTER IS OK)
CHECK R/G/B SIGNAL OF VIDEO PCB ?
NO
TROUBLE IN SIGNAL CABLE
YES
CHECK IC301 PIN 35, 30, 25 ? (R/G/B SIGNAL)
NO
TROUBLE IN IC301 B+ (12V) LINE, IC301 CIRCUIT
YES
CHECK IC302 PIN 14, 6, 4 ? (R/G/B SIGNAL)
NO
TROUBLE IN IC302 B+ (12V, 75V) LINE, Q301, Q302, Q303
YES
TROUBLE IN CDT
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5. NO RASTER
NO RASTER (POWER INDICATOR IS GREEN)
CHECK C939 DC VOLTAGE ? (175V) YES CHECK IC701 PIN 6, 7 WAVEFORM ? YES CHECK Q711 COLLECTOR PULSE ? (1000Vpp) YES CHECK Q401 COLLECTOR PULSE ? (600~800Vpp) YES CHECK G1 VOLTAGE OF CDT (BRIGHTNESS MAX) ? (0~-20V) YES CHECK HEATER VOLTAGE OF CDT ? (6.0~6.3V) YES TROUBLE IN FBT (TOO LOW FBT SCREEN VOLTAGE)
NO
REFER TO NO POWER FLOW CHART
NO
TROUBLE IN IC701 B+ (12V) LINE
NO
TROUBLE IN Q710, D717, D431
NO
TROUBLE IN Q402, Q403, Q404, D403, D404
NO
TROUBLE IN Q210, Q211, Q214, Q215, Q216, Q217, D776, R710
NO
TROUBLE IN R986, Q960, D924, C938, IC901, P702-P303
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6. TROUBLE IN H-LINEARITY
UNBALANCE OF H-LIN.
CHECK IC801 PIN 13, 14, 20, 21 VOLTAGE ?
NO
TROUBLE IN IC801(MICOM), R848, R849, R850, R851
YES
CHECK Q511, Q520, Q521, Q522, Q523, Q524, Q525, Q526, Q527 ?
NO
TROUBLE IN Q511, Q520~Q527
YES
TROUBLE IN 12V LINE, RL501, C514, C515, C517, C519, C523, C525
Cs SIGNAL TABLE HORIZONTAL FREQUENCY(fH) 30.0~33.0kHz 33.1~36.5kHz 36.6~43.0kHz 43.1~53.0kHz 53.1~59.0kHz 59.1~65.0kHz 65.1~75.0kHz 75.1~85.0kHz 85.1~95.0kHz PIN 21 L L L H H H H H H IC801(MICOM) PIN 20 PIN 14 L L H L H H H H H L H H H L L H H H PIN 13 L L L L L H L H H H: High L : Low
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7. NO VERTICAL DEFLECTION
NO VERTICAL DEFLECTION (ONE HORIZONTAL LINE)
CHECK IC601 PIN 3 ? (13V)
NO
TROUBLE IN R603, D930 D601, D602
YES
CHECK IC601 PIN 6 ? (50V)
NO
TROUBLE IN R608, D929
YES
TROUBLE IN IC601, VERTICAL DEFLECTION CIRCUIT
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8. NO DEGAUSSING
NO DEGAUSSING
(
BUTTON MUST BE PRESSED)
CHECK IC801 PIN 49 ? (LOW)
NO
TROUBLE IN IC801(MICOM), R852, R943
YES
CHECK Q904 COLLECTOR ? (5V)
NO TROUBLE IN Q904
YES
CHECK P902 CONNECTOR ?
NO TROUBLE IN Q902
YES
CHECK RL901 ?
NO TROUBLE IN RL901
YES
TROUBLE IN TH902, DEGAUSSING COIL
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9. NO TILT (NO ROTATION)
NO TILT (NO ROTATION)
CHECK IC602 PIN 5 ? (0 5V)
NO
TROUBLE IN IC801(MICOM), R811, R610
YES
CHECK IC602 ? B+(12V), B ( 12V)
NO
TROUBLE IN D775, R709
YES
TROUBLE IN IC602, Q601, Q602, P602, TILT COIL
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10. TROUBLE IN OSD
NO OSD
CHECK IC303 PIN 7, 8 CLOCK PULSE ? (WHEN ENTER BUTTON IS PRESSED)
NO
TROUBLE IN P802-P552, P553-P302, IC801 (MICOM), R836, R837
YES
CHECK IC303 PIN 5, 18 WAVEFORM ?
NO
TROUBLE IN P553-P302, Q304, Q305, D302, R376, R377, R378, R386
YES
CHECK IC303 PIN 4, 17 ? (5V)
NO
TROUBLE IN D301, R308
YES
TROUBLE IN IC801, IC303
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11. TROUBLE IN OSD BUTTON CONTROL (OSD IS NORMAL)
* BUTTON or CONTROL KEY MUST BE PRESSED DURING CHECKING.
NO BRIGHT UP/DOWN NO DIRECTION RIGHT
CHECK IC801 PIN 18 WAVEFORM AND VOLTAGE ? YES SEE BELOW TABLE
NO
TROUBLE IN CONTROL PCB KBD2 CIRCUIT, Q244~Q246, Q241~Q243, IC201, IC202, VR201, VR202, P801-P201, P202-P203
TROUBLE IN IC801
NO POWER ON/OFF, NO CONTRAST UP/DOWN, NO ENTER OPERATING, NO DIRECTION LEFT
CHECK IC801 PIN 18 WAVEFORM AND VOLTAGE ? YES SEE BELOW TABLE
NO
TROUBLE IN CONTROL PCB KBD2 CIRCUIT, Q250~Q252, Q247~Q249, IC201, IC202, VR201, VR202, P801-P201, P202-P203
TROUBLE IN IC801
KBD1,2 VOLTAGE AND WAVEFORM TABLE
KEY OPERATING BRIGHT UP BRIGHT DOWN DIRECTION RIGHT CONTRAST UP CONTRAST DOWN POWER ON/OFF ENTER DIRECTION LEFT IC801 PIN 19 VOLTAGE 0.25V 5.0V * 5.0V * 1.75V * 5.0V 5.0V 0.25V 0.75V 1.25V IC801 PIN 18 VOLTAGE 0.25V 2.75V 2.25V 5.0V 3.75V * 3.25V * 5.0V 5.0V 5.0V *
2.75V (ACTIVE) 0V
NOTE: * Marks are checked with oscilloscope.
ex. BRIGHT UP
5V
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