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TROUBLESHOOTING GUIDE
BASIC GUIDE
CHECK SMPS SECONDARY B+ OUTPUT
NO
FOLLOW NO POWER PROCEDURE
YES
CHECK HORIZONTAL OUTPUT WAVEFORM
NO
FOLLOW NO RASTER PROCEDURE
YES
CHECK VERTICAL OUTPUT WAVEFORM
NO
FOLLOW NO VERTICAL DEFLECTION PROCEDURE
YES
CHECK VIDEO OUTPUT WAVEFORM
NO
FOLLOW NO CHARACTER, NO CONTRAST PROCEDURE
YES
FOLLOW OTHER PROCEDURES
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1. NO POWER
NO POWER
CHECK C908 DC VOLTAGE? DC=MORE THAN 130V YES
NO
TROUBLE IN F901, R901, D901, D902
CHECK T901 PIN 3 ?
NO
CHECK IC901
NO
TROUBLE IN Q901, Q902, IC901,R904, R905, R912, D906, D907
YES YES TROUBLE IN D909, R916 CHECK SMPS SECONDARY DC VOLTAGE ? TROUBLE IN D931~D933, D936 OR THEIR CONNECTED COMPONENTS
NO
6.3V, 14V, 50V, 72V YES
CHECK IC931 PIN 3 VOLTAGE (5V)?
NO
TROUBLE IN IC931 CIRCUIT
YES
TROUBLE IN OTHER PRIMARY CIRCUIT
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2. NO CHARACTER
NO CHARACTER
CHECK IC301 PIN 8 (8V)? YES
NO
TROUBLE IN IC302 14V LINE
CHECK IC301 PIN 2, 4, 6 ? YES
NO
TROUBLE IN PC SIGNAL, C301, C302, C303
CHECK IC301 PIN 19 ? YES CHECK IC301 PIN 11, 15, 18 ?
1.2v
NO
TROUBLE IN CLAMP CIRCUIT
NO
TROUBLE IN IC301 CIRCUIT
YES
CHECK VIDEO OUTPUT Q341, Q351, Q361 ? YES CHECK R, G, B CATHODE VOLTAGE ? NORMAL=44~67V YES CHECK IC301 PIN 9 YES TROUBLE IN CDT SOCKET
NO VIDEO OUTPUT: Q341, Q342, Q343, Q344, Q351, Q352, Q353, Q354, Q361, Q362, Q363, Q364 NO
TROUBLE IN IC301 CIRCUIT
TROUBLE IN VR347, VR357, VR367
NO
FOLLOW NO CONTRAST PROCEDURE
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3. NO RASTER
NO RASTER
(LED COLOR IS GREEN)
CHECK CDT HEATER VOLTAGE? (6.3 0.6V)
? ? ? ?e?@@@@@@@@@@@@@@@@? ?e?@@@@@@@@@@@@@@@@? ? ? ?eh@@ ?eh@@ ?eh@@ ?eh@@ ?eh@@ ?eh@@ ?e?@@@@@@@@@@@@@@@@? ?e?@@@@@@@@@@@@@@@@? ?eh@@ ?eh@@ ?eh@@ ?eh@@ ?eh@@ ?eh@@ ? ? ? ? ?
NO
TROUBLE IN HEATER VOLTAGE SUPPLY CIRCUIT ( Q935, Q936 etc)
YES
CHECK CRT G1 (0 ~ -50V)?
NO
TROUBLE IN G1 SUPPLY CIRCUIT (D793, C785, Q722, Q724, Q756, D794, D797 etc)
YES
CHECK R, G, B CATHODE OF CDT?
NO
FOLLOW NO CHARACTER PROCEDURE
YES
CHECK FBT PIN 2 DC 65~150V?
NO
FOLLOW NO POWER PROCEDURE
YES
CHECK FBT PIN 1?
NO
CHECK HORIZONTAL DEFLECTION CIRCUIT
1.000 ~1.200VP-P
YES
CHECK MUTE OR DPM CIRCUIT
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4. TROUBLE IN H/V SIZE, H/V POSITION, S-PCC, TRAPEZOID
NO ADJUSTED H-/V SIZE, POSITION, S-PCC, TRAP.
CHECK IC401 PIN 1, 2, 3, 38, 39, 40 ?
NO
TROUBLE IN IC401 (MICOM)
YES
CHECK IC701 PIN17, 18, 20, 21, 30, 32?
NO
TROUBLE IN IC701
YES
TROUBLE IN PWM CIRCUIT
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5. NO VERTICAL DEFLECTION
NO V-DEFLECTION (ONE HORIZONTAL LINE)
CHECK IC601 PIN 3 (14V)?
NO
TROUBLE IN 14V LINE, R601, C601
YES
CHECK IC601 PIN 7 (40V)?
NO
TROUBLE IN 50V LINE, R602, C604
YES
CHECK IC701 PIN 12, 13?
NO
TROUBLE IN IC701
YES
TROUBLE IN IC601, V- DEFLECTION CIRCUIT
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6. NO CONTRAST
NO CONTRAST
CHECK Q742?
NO
TROUBLE IN Q742
YES
CHECK Q743?
NO TROUBLE IN Q743
YES
CHECK IC301 PIN 9 ?
NO
TROUBLE IN P902, P302, VR850
DC 0.8~5V YES
TROUBLE IN IC301
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7. TROUBLE IN DPM
OFF MODE FAILURE
(NO OFF MODE)
CHECK IC401 PIN 41, 42 (H/V SYNC)
NO H/V SYNC SIGNAL
CHECK PC, (PC IS NOT GOING INTO DPM OFF MODE) Q451, Q452
INPUT H/V SYNC
CHECK IC401 PIN 8, 9 WAVEFORM? (4MHz)
NO
TROUBLE IN X401, IC401 (MICOM)
YES
CHECK IC401 PIN 20, 21 ?
NO
TROUBLE IN IC401 (MICOM)
YES
CHECK B+ LINE (6.3V, 14V) ?
NO
TROUBLE IN B+ LINE
YES
TROUBLE IN PC
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8. TROUBLE IN AUDIO
NO AUDIO (NO SOUND)
BEFORE REPAIR, PC OR SOFTWARE SHOULD BE CHECKED.
CHECK AUDIO INPUT CABLE ?
NO
TROUBLE IN AUDIO INPUT CABLE
YES
CHECK IC501 PIN 14, 15, 16, 17?
NO
TROUBLE IN IC501(TDA7496L)
YES
TROUBLE IN SPEAKER
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9. NO DEGAUSSING
NO DEGAUSSING
CHECK Q941?
NO
TROUBLE IN Q941, IC401
YES
CHECK Q941 COLLECTOR VOLTAGE?
NO
TROUBLE IN Q941, RL901
YES
CHECK P903?
NO
TROUBLE IN P903
YES
CHECK RL901?
NO
TROUBLE IN RL901
YES
TROUBLE IN TH901, DEGAUSSING COIL
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