Page 1
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TROUBLESHOOTING GUIDE
NO POWER
(POWER INDICATOR OFF)
TROUBLE IN D900
TROUBLE IN FUSE
(F901)
TROUBLE IN
IC901
TROUBLE IN
D941, D942, D951,
D961, D962, D971
TROUBLE IN
Q903, Q952,
Q951, Q942, Q941
CHECK
FUSE OK?
(F901)
CHECK
C908 VOLTAGE?
(AC120V: 160VDC,
AC220V: 304VDC)
NO
YES
YES
YES
YES
NO
NO
NO
CHECK
IC901 PIN 6
WAVEFORM
(SQUARE WAVE
COMES OUT?)
CHECK
D941, D942, D951,
D961, D962, D971
VOLTAGE?
1. NO POWER
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2. NO CHARACTER
NO CHARACTER
CHECK
IC302
PIN 9 (5V) ?
CHECK
IC302 PIN 5, 6, 7 ?
CHECK
IC302 PIN 18, 19, 20 ?
CHECK
IC303
PIN 1, 2, 3 ?
CHECK
IC303 PIN 4 (80V)
PIN 8 (12V) ?
TROUBLE IN
P302 5V LINE
TROUBLE IN
PC SIGNAL,
P301 SIGNAL CABLE
TROUBLE IN
IC302
TROUBLE IN
P303 12V LINE/
80V LINE
TROUBLE IN IC303
NO
YES
NO
NO
YES
YES
YES
YES
NO
NO
CHECK
R, G, B CATHODE
VOLTAGE?
TROUBLE IN
R331~R333,
L311~L313
D307~D312
TROUBLE IN
CRT SOCKET
YES
NO
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NO VIDEO
(POWER INDICATOR ON)
CHECK
POWER INDICATOR
GREEN or ORANGE?
CHECK
D712 ANODE
(-157V)?
CHECK
G1VOLTAGE?
(-55 ~ -15V)
TROUBLE IN
D712
TROUBLE IN
Q799
DPM MODE
(NO H and/or V SYNC)
ORANGE
NO
GREEN
YES
NO
3. NO RASTER
CHECK
CDT HEAT
VOLTAGE? (6.3V)
TROUBLE IN
D941, Q942, Q941
YES
NO
TROUBLE IN
CDT
YES
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4. NO HORIZONTAL DEFLECTION
NO H-DEFLECTION
(ONE VERTICAL LINE)
CHECK
Q706?
CHECK
B+ VOLTAGE
(50V)?
CHECK
T701(FBT) PIN 2
(31KHZ, 60V
69KHZ, 140V ?
CHECK
Q701 COLLECTOR
WAVEFORM?
TROUBLE IN
Q706
TROUBLE IN
50V LINE
TROUBLE IN
Q719, Q720, D710
TROUBLE IN
Q701
TROUBLE IN
T701, P701
NO
NO
YES
YES
YES
YES
NO
NO
0V
T
Page 5
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5. TROUBLE IN H-LINEARITY
UNBALANCED OF H-LIN.
CHECK
IC401
PIN 5, 6, 7 ?
CHECK
Q711~Q716?
CHECK
L703?
TROUBLE IN
IC401 (MICOM)
TROUBLE IN
Q711 ~ Q716
TROUBLE IN
L703
TROUBLE IN
C722, C723, C726, C729
NO
NO
NO
YES
YES
YES
Cs SIGNAL TABLE
HORIZONTAL
FREQUENCY(fH)
30K ~ 33.9K
34K ~ 38.9K
39K ~ 44.9K
45K ~ 48.9K
49K ~ 57.9K
58K ~ 65.9K
66K ~ 70K
Cs1
L
L
H
L
H
L
H
Cs3
L
L
L
H
H
H
H
Cs2
L
H
H
L
L
H
H
Page 6
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6. NO VERTICAL DEFLECTION
NO V-DEFLECTION
(ONE HORIZONTAL LINE)
CHECK
IC601 PIN 3
(15V)?
CHECK
IC601 PIN 7
(40V)?
CHECK
IC701 PIN 12, 13?
TROUBLE IN
R603 15V LINE
TROUBLE IN
HIGH-VOLTAGE OUT
CIRCUIT(FBT),
D721, R606
TROUBLE IN
IC701
TROUBLE IN
IC601, V-CIRCUIT
NO
NO
YES
YES
YES
NO
3V
Page 7
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TROUBLE IN
OSD PERIPHERAL
CIRCUIT
NO OSD
TROUBLE IN
5V LINE
TROUBLE IN
IC601 PIN8 (V-FBP),
T701 40V LINE (H-FBP)
TROUBLE IN
IC302, IC301
TROUBLE IN
IC301, IC302
NO
YES
DC 5V
YES
YES
YES
NO
NO
NO
Pin 5
5V
Pin 10
5V
H+V
5V
H+V
CHECK
IC301 B
+
?
CHECK
IC301 PIN 12
WAVEFORM ?
(ENTER BUTTON MUST BE PRESSED.)
7. TROUBLE IN OSD
CHECK
IC301 PIN 5, 10
WAVEFORM?
CHECK
IC301 PIN 13, 14, 15 ?
Page 8
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CHECK
IC401 (MICOM)
PIN 31, 32 (H/V INPUT)
SIGNAL?
CHECK
IC401 PIN 13
WAVEFORM?
CHECK
IC401 (MICOM)
PIN 2, 3 ?
CHECK
B+LINE
(6.3V,15V, 80V) ?
CHECK PC,
(PC IS NOT GOING INTO
DPM OFF MODE)
TROUBLE IN
X401
TROUBLE IN
IC401 (MICOM)
TROUBLE IN
Q941, Q942, Q951, Q952,
TROUBLE IN PC
OFF MODE FAILURE
INPUT H/V SYNC SIGNAL
H/V SYNC
(NO OFF MODE.)
NO
NO
NO
NO (DPMF: 0V)
DPM TABLE
Mode
Item
NORMAL
STAND-BY
SUSPEND
OFF
DPMF
H
H
H
L
LED
GREEN
AMBER
AMBER
AMBER
DPMS
H
L
L
L
YES
YES
SEE DPM TABLE
YES
YES
8. TROUBLE IN DPM
5V
24MHz
Page 9
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CHECK
IC401 PIN 19
(0V)?
CHECK
Q953 COLLECTOR
VOLTAGE?
CHECK
P902 ?
CHECK
RL901?
TROUBLE IN
IC401 (MICOM)
TROUBLE IN
Q953
TROUBLE IN
P902
TROUBLE IN
RL901
TROUBLE IN
TH901,
DEGAUSSING COIL
NO DEGAUSSING
DC 15V
NO
NO
NO
NO
YES
YES
YES
YES
(DEGAUSS ON THE OSD MENU MUST BE PRESSED.)
9. NO DEGAUSSING
Page 10
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10. NO TILT (NO ROTATION)
NO TILT (NO ROTATION)
TROUBLE IN
IC401 (
MICOM)
TROUBLE IN
15V LINE, 6.3V LINE
TROUBLE IN
Q501~Q503
TROUBLE IN
P501, TILT COIL, D501
NO
YES
YES
YES
CHECK
15V LINE
AND 6.3V LINE ?
CHECK
Q503 EMITTER
VOLTAGE ?
NO
NO
CHECK
IC401 PIN 21
WAVE FORM ?
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