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SERVICE MANUAL
it obtains the output voltage (+5V, +3.3V, 8V, 12V, 18V, 28V) passing through
voltage control circuit.
7-4-2. Fuse Open
7-4-2-1. check D1, 2, 3, 4 and repaier if there are N.G
7-4-2-2. check Q1 and repaier if there are N.G
7-4-3. No Output
Observe the DRAIN Voltage Signal wave connecting Q1 DRAIN and GND of the SMPS by
using an Oscilloscope.
If the previous Channel Output is not appeared, it means the state of Current
Limit of SMART IC ocurred by a damage of the components.
In this case, the components have to be checked as follows:
7-4-3-1. check OPT1, and repaier if it is N.G
7-4-3-2. check D7, 8, 9, 10, 11, 12 and repaier if there are N.G
7-4-3-3. check IC1, and repaier if it is N.G
Verify the Channel Pattern or an existence of bad connection among components
in thd case of
7-4-3-4. +3.3V : check D8, L3, J26 and wire pin 4
7-4-3-5. +12V : check D11, L4, J33 and wire pin 7
7-4-3-6. +8V
7-4-3-7. +18V : check D9, L6, J17, J26 and wire pin 11
7-4-3-8. +28V : check D12, BD2, J24 and wire pin 9
S-00-005(96.03.27)
- normal wave form -
figure 7-4-3. Q1 switching voltage wave form
certain Channel voltage level is not reachec
: check D10, L5, J30, J23 and wire pin 8
REV.1
Document No
Date of Origin
Date of REV
- unnormal wave form -
PAGE REV.
0
51-L-DSR004
98-10-21
PAGE
30/102
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