FAULT FINDING
- This trouble shooting guide is arranged by fault conditions. Following each fault condition is a check for a signal on condition to be answered YES or NO.
- For NO answer proceed to the right and continue until the fault is located.
- For a YES answer continue in the left column to the next numbered check.
- Again followed this procedure until the fault is located.
- When Troubleshooting this monitor, some precaution should be observed.
- Use a high quality isolation tranformer is capable of providing 3 Amps or more.
- Never connect primary ground and secondary ground together including use with an isolation transformer.
- Measure high voltage with respect to chassing ground only, and with a high impedance prove of 1000 mega-ohm or higher and rated for 30KV DC or higher.
- Measure QH09 collector pulse with a high quality 100:1 probe rated for 1500 volts or higher.
Symptom
|
Check(YES)
|
Action(NO)
|
Image
is scrolling
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1)
Check for Vsync at pin 40 of ICM01
|
Check 15 pin D-sub
connector, cable, ZDM02
|
2) Check for positive going
Vsync at pin
2 of ICH01.
|
Check
ICM01, ICH01
|
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3)
Will V-oscillator is locked with input signal? (pin 22 of ICH01)
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Check
CH01, CH02, RH05
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4)
Check V-amp at pin 23 of ICH01.
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Replace
ICH01.
|
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5)
Check V-out at pin 5 of ICV01.
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Check
B+ at pin 4,6 of ICV01.
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1)
Check for Hsync at pin 39 of ICM01
|
Check 15 pin D-sub
connector, cable,
ZDM01.
|
|
Image
is unstable.
|
2) Check for positive going
Hsync at pin
1 of ICH01.
|
Check
ICM01, ICH01
|
3)
Will H-oscillator is locked with input signal? (pin 6 of ICH01)
|
Check
CH06, RH06
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4)
Check H-out at pin 26 of ICH01
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ReplaceICH01
|
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5)
Check for flyback pulse at pin 12 of ICH01.
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Check
RH10
|
|
1) Check for G2, pin4 of
CRT.
Around
500 volts?
|
Check
DH28, RH94, RH92, CH53, CRT socket. G2 Wire
|
|
Screen
is black but high voltage is present.
|
2) Check for heater voltage
at pin 6 of CRT.
(about 6.3V)
|
Check
DP13, RP24, RP25, QP05, QP06 CRT socket. RC55, BC04, CNC01
|
3) Can screen be lit with
brightness control
at MAX?
|
Check DH21, DH25, QH18,
QH19, RH85
CRT socket. RH82, RH83
|
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4) Check for video at pin
5, 8, 10 of ICC01
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Check 15 pin D-sub
connector, cable, DC13,
DC14, DC15
|
|
5)
Check for positive pulse for clamp at pin 18 of ICC01.
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Check
ICM01, ICH01
|
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6)
Check if contrast controls video level at pin 21, 24, 26 of ICC01.
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Check
ICM01, RH24, ICC01
|
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7) Check for video at pin
1, 2, 3 of ICC03.
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Check ICC03,80 75VDC(pin 4) 12VDC(pin 8)
|
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8)
Check if R, G, B cut-off control the video DC level at pin 6, 8, 11 of CRT.
|
Check
QC03 to QC08
|
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9)
Check CRT.
|
||
1)
Is the LED01 lighting in Green color.
|
Check H.V Sync at pin39, 40
of ICM01. Check pin 7, 8 of ICM01.
Check
ICM01, ICM02,ICC03
|
|
Screen
is black with no high voltage.
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2)
Check for 14V at collector of QP07.
|
Check
QP07, QP08. Check pin 9 of ICM01.
Check for Vcc at pin 29 of
ICH01.
Check oscilation pulse at
pin 29 of ICH01.
Check X-Ray voltage below
6.2V at pin
2 of ICH01.
Check
RH11, RH12, RH13
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3) Check output pulse at
pin 6, 8 of ICH01.
|
Check for Vcc at pin 29 of
ICH01.
Check oscilation pulse at
pin 29 of ICH01.
Check X-Ray voltage below
6.2V at pin
2 of ICH01.
Check
RH11, RH12, RH13
|
|
4) Check Hor-Drive pulse at
Base of QH09.
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Check
QH08, TH01.
|
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5)
Check B+ at pin 2 of TH04.
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Check DH07, LH01, QH07,
QH04,QH05, QH06, QH51, RH41,
RH42,RH39,
RH18, ICH01
|
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No
power
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1)
Check ICP01 pin 4, 7
2)
Check switch pulse at Drain of QP04.
3)
Check voltage for, 55V at Cathode of Dp11 and for 7V at Cathode of DP13 and
for 14V at cathode of DP15
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Check
QP01, QP02, DP05,
DP09, TP02.
Check
pin 6, 3 of ICP01.
Recheck
above Item(d).
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