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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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