Emerson EWC1902 Service Manual Page 37
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1-8-15 T5300TR1
Check Fuse (F601) is blown
out or not.
If fuse is blown out,
do repair method #1
Check whether the primary
rectifying DC of the Switching
power supply has an output.
(Reading should be about 168V.
Voltage of the 105V line
higher than normal?
The transformer of the power
supply makes a higher sound
or the oscillation wave form is
abnormal.
(E.g. intermittent oscillation)
Connect the positive probe of
oscilloscope to the pin 16 of
T601, then connect the negative
probe to the pin 12. Observe the
waveform and check to see if
the waveform is out of limit of
value shown in Fig.1.
There is no problem on the
SW power supply
CHECK
#1
#2
#3
#4
Repair method
NO
NO
NO
YES
YES
YES
YES
NO
Power Supply Trouble Shooting Guide
It is highly recommended that a variable isolation
transformer which can monitor current be used.
(Alternatively a variable AC source which moni-
tors current will do). Read directions below before
power is added!
Repair method #1
(Power must be off)
Short circuit in the secondary side. check diode D613,
D614, D616, D617 and D618, switching transistor
(Q601), control transistor (Q602), diode and resistor
replace as necessary.
Disconnect 105V diode (D613), 25V diode (D614), 8V
diode (D616), 12V diode (D617), 12V diode (D618)
and Check the load continuity of 105V line, 25V line,
8V line, 12V line through a tester (resistance range).
If the tester indicates a lower resistance value around
0 ohm, the line is short-circuited.
Before repairing the switching power supply, find out
the short-circuited area of such line and repair it.
If the tester does not indicate any low resistance value
(around 0 ohm), no load is short-circuited and there is
no problem.
Check for any defective parts while the secondary rec-
tifying diodes are disconnected (D613, D614, D616,
D617 and D618) perform a diode check in both for-
ward and reverse directions through a tester.
Fig.1
0V
Voltage approx. 5Vp-p
T=Approx. 6 to 14 sec
Oscilloscope setting: 1V/DIV.
2 sec./DIV
- SERVICE MANUAL 1
- IMPORTANT SAFETY NOTICE 2
- MAIN SECTION 3
- SPECIFICATIONS 4
- <AUDIO> 5
- IMPORTANT SAFETY PRECAUTIONS 6
- Precautions during Servicing 8
- Safety Check after Servicing 9
- STANDARD NOTES FOR SERVICING 10
- Tweezers 11
- Soldering Iron 11
- Presolder 12
- Flat Pack-IC 12
- Instructions for Handling 13
- Semiconductors 13
- PREPARATION FOR SERVICING 14
- 1 92 3 4 5 6 7 8 15
- 1011 1412 15
- [1] Rear Cabinet 17
- [2] Tray Chassis 17
- [4] Main CBA 17
- [3] Deck Unit 17
- 1-6-2 T7300DC 18
- 1-6-3 T7300DC 19
- 1-6-4 T7300DC 20
- 1-6-5 T7300DC 21
- Fig. 1-1 22
- Remote control unit (Bottom) 22
- 3. TV AGC Adjustment 23
- 4-1. H Adjustment 23
- 4-2. C-Trap Adjustment 23
- 4-3. Y DL Time Adjustment 24
- 5. V. Size Adjustment 24
- 6. V. Shift Adjustment 24
- PATTERN GENERATOR 25
- RF INPUT 25
- 9. Sub-Brightness Adjustment 26
- 10. Focus Adjustment 26
- 12. CCS Text Box Location 26
- 13.Purity Adjustment 27
- 14. Convergence Adjustment 27
- BLOCK DIAGRAMS 29
- Video Block Diagram 30
- Audio Block Diagram 31
- Chroma/Tuner Block Diagram 32
- CRT/H.V. Block Diagram 33
- HOT COLD 34
- MECHANICAL TROUBLE INDICATOR 35
- Countermeasure for Mechanical 36
- Malfunction 36
- Repair method #1 37
- Repair method #2 38
- Repair method #3 38
- Repair method #4 38
- Standard Notes 39
- T7300SCM1 41
- 1-9-6 1-9-7 1-9-8 T7300SCM2 42
- T7300SCM3 43
- Main 4/4 Schematic Diagram 44
- Main CBA Top View 45
- Sensor CBA 45
- Top View 45
- (START-SENSOR) 45
- Main CBA Bottom View 46
- CRT CBA Top View 47
- CRT CBA Bottom View 47
- Z11WF1-10-1 1-10-2 48
- WIRING DIAGRAM 49
- SYSTEM CONTROL TIMING CHARTS 50
- IC PIN FUNCTION DESCRIPTIONS 52
- LEAD IDENTIFICATIONS 54
- DECK MECHANISM 55
- STANDARD MAINTENANCE 56
- A/C Head 57
- J-1-1, J-1-2 58
- Cam Gear 59
- LDG Belt (B) 59
- Incorrect 61
- Waveform 62
- Erase Head 62
- OF DECK MECHANISM 63
- [20],[23] 63
- Lead with 66
- Blue Stripe 66
- Lead with White Stripe 67
- Fig. DM11 68
- Fig. DM12 68
- Fig. DM14 69
- Fig. DM13 69
- Fig. DM15 70
- Fig. DM16 70
- Fig. DM17 70
- Fig. DM18 70
- Alignment 3 72
- Cam Gear (A), Rack Assembly 72
- EXPLODED VIEWS AND 73
- PARTS LIST SECTION 73
- EXPLODED VIEWS 74
- 3-1-3 T7300PEX 75
- DECK EXPLODED VIEWS 76
- Deck Mechanism View 2 77
- Deck Mechanism View 3 78
- MECHANICAL PARTS LIST 79
- CRT Warning Label 80
- CRT Type No 80
- ELECTRICAL PARTS LIST 81
- 20020205 3-3-2 T7300EL 82
- 20020205 3-3-3 T7300EL 83
- 20020205 3-3-4 T7300EL 84
- 20020205 3-3-5 T7300EL 85
- 20020205 3-3-6 T7300EL 86
- 20020205 3-3-7 T7300EL 87
- 20020205 3-3-8 T7300EL 88
- 20020205 3-3-9 T7300EL 89
- SENSOR CBA 90
- DECK PARTS LIST 91
- B359 CLEANER LEVER B361 91
- Type ID No. ID No 91
- A 0VM304413 0VM411114 91
- B 0VM305090 Not used 91
- Printed in Japan 92
- 2002-02-20 HO 92
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