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TROUBLE SHOOTING GUIDE
BASIC GUIDE
CHECK FOLLOW
NO
SMPS SECOND NO POWER
B+ OUTPUT PROCEDURE
YES
CHECK
HORIZONTAL NO FOLLOW
OUTPUT NO RASTER
WAVEFORM PROCEDURE
YES
FOLLOW
CHECK NO NO VERTICAL
VERTICAL OUTPUT
DEFLECTION
WAVEFORM
PROCEDURE
YES
CHECK FOLLOW
VIDEO OUTPUT NO
NO CHARACTER,
WAVEFORM NO CONTRAST
PROCEDURE
YES
FOLLOW OTHER
PROCEDURES
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1. NO POWER
NO POWER
CHECK C908 NO
TROUBLE IN
DC VOLTAGE?
F901, R901, D901, D902
DC=MORE THAN 130V
YES
CHECK TROUBLE IN
NO CHECK NO
T901 Q901, Q902, IC901,R904,
PIN 3 ? IC901 R905, R912, D906, D907
YES
YES
TROUBLE IN
D909, R916
CHECK TROUBLE IN
SMPS SECOND NO D931~D933, D936, D937
DC VOLTAGE ? OR THEIR CONNECTED
COMPONENTS
6.3V, 11.5V, 39V,
65V, 77V
YES
CHECK
NO TROUBLE IN
IC931 PIN 3
IC931 CIRCUIT
VOLTAGE (5V)?
YES
TROUBLE IN
OTHER PRIMARY CIRCUIT
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2. NO CHARACTER
NO CHARACTER
CHECK NO TROUBLE IN
IC301 PIN 8 (8V)? IC302 11.5V LINE
YES
CHECK NO TROUBLE IN
IC301 PIN 2, 4, 6 ? PC SIGNAL,
C301, C302, C303
YES
CHECK NO TROUBLE IN
IC301 PIN 19 ? CLAMP CIRCUIT
YES
CHECK NO TROUBLE IN
IC301 PIN 11, IC301 CIRCUIT
15, 18 ?
1.2v
YES
CHECK
VIDEO OUTPUT NO TROUBLE IN
Q341, Q351, Q361 ? IC302 CIRCUIT
VIDEO OUTPUT:
Q341, Q342, Q343, Q344,
Q351, Q352, Q353, Q354,
YES
Q361, Q362, Q363, Q364
CHECK TROUBLE IN
NO
R, G, B CATHODE VR347, VR357, VR367
VOLTAGE ?
NORMAL=44~67V
YES
CHECK NO FOLLOW
IC301 PIN 9 NO CONTRAST
PROCEDURE
YES
TROUBLE IN
CRT SOCKET
- 16 -
3. NO RASTER
NO RASTER (LED COLOR IS GREEN)
CHECK TROUBLE IN
NO HEATER VOLTAGE
CRT HEATER VOLTAGE?
(6.3 0.6V) SUPPLY CIRCUIT
( Q935, Q936 etc)
YES
CHECK TROUBLE IN
NO
CRT G1 (0 50V)? G1 SUPPLY CIRCUIT
(D793, C785, Q722,
Q724, Q756, D794,
D797 etc)
YES
CHECK FOLLOW
R,G,B CATHODE NO
NO CHARACTER
OF CRT? PROCEDURE
YES
CHECK FOLLOW
NO NO POWER
FBT PIN 2
DC 65~150V? PROCEDURE
YES
CHECK NO CHECK HORIZONTAL
FBT PIN 1? DEFLECTION CIRCUIT
1.000
~1.200VP-P YES
CHECK MUTE OR DPM
CIRCUIT
- 17 -
4. TROUBLE IN H/V SIZE, H/V POSITION, S-PCC, TRAPEZOID
NO ADJUSTED H-/V SIZE,
POSITION, S-PCC, TRAP.
CHECK NO TROUBLE IN
IC401 PIN 1, 2, 3,
IC401 (MICOM)
38, 39, 40 ?
YES
CHECK NO TROUBLE IN
IC701 PIN17, 18, 20, 21,
IC701
30, 32?
YES
TROUBLE IN
PWM CIRCUIT
- 18 -
5. NO VERTICAL DEFLECTION
NO V-DEFLECTION
(ONE HORIZONTAL LINE)
CHECK NO TROUBLE IN
IC601 PIN 3
(11.5V)? 11.5V LINE, R601, C601
YES
CHECK NO TROUBLE IN
IC601 PIN 7
39V LINE, R602, C604
(39V)?
YES
CHECK NO TROUBLE IN
IC701 PIN 12, 13? IC701
YES
TROUBLE IN
IC601, V-CIRCUIT
- 19 -
6. NO CONTRAST
NO CONTRAST
CHECK NO TROUBLE IN
Q742 Q742
YES
CHECK NO
TROUBLE IN
Q743 Q743
YES
CHECK NO TROUBLE IN
IC301 PIN 9 ?
P702, P703,
VR852
DC 0.8~5V
YES
TROUBLE IN
IC301
- 20 -
7. TROUBLE IN DPM
OFF MODE FAILURE (NO OFF MODE)
CHECK CHECK PC,
IC401 PIN 41, 42 NO H/V SYNC SIGNAL (PC IS NOT GOING INTO
(H/V SYNC) DPM OFF MODE)
Q451, Q452
INPUT H/V SYNC
CHECK
IC401 PIN 8, 9 NO TROUBLE IN
WAVEFORM? X401, IC401 (MICOM)
YES
CHECK
NO TROUBLE IN
IC401
IC401 (MICOM)
PIN 20, 21 ?
YES
CHECK NO TROUBLE IN
B+ LINE (6.3V, 11.5V) ? B+ LINE
YES
TROUBLE IN
PC
- 21 -
8. NO DEGAUSSING
NO DEGAUSSING
CHECK NO TROUBLE IN
Q941 ? Q941, IC401
YES
CHECK
NO TROUBLE IN
Q941 COLLECTOR
Q941, RL901
VOLTAGE?
YES
CHECK NO TROUBLE IN
P903? P903
YES
CHECK NO TROUBLE IN
RL901? RL901
YES
TROUBLE IN
TH901,
DEGAUSSING COIL
- 22 -