SERVICE MANUAL
Document No
Date of Origin
Date of REV
51-L-DSR004
98-10-21
PAGE REV.
0
PAGE
30 /102
S-00-005(96.03.27)
REV.1
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.
- normal wave form -
- unnormal
wave form -
figure 7-4-3. Q1 switching
voltage
wave form
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
certain
Channel
voltage
level is not reachec
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
: check D10, L5, J30, J23 and wire pin 8
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
