Bru-300/300P; Trouble When Power-On The Unit - Sony BRC-300 Service Manual

4-4. BRU-300/300P

4-4-1. Trouble when Power-on the Unit

c-1. The power indicator does not light and image is not displayed after power-on.
c-1
Does +12 V exist
in CL4001 on the
MC board ?
Yes
Are the fuses F4001
to F4003 normal
on the MC board ?
Yes
Are the power
supply lines (+2.5 V,
+3.3 V, +5.0 V, and
_5.0 V) normal on
the MC board ?
Yes
Is the 25 MHz
signal input to pins 96,
97 of IC3518 on the
MC board ?
Yes
Is the pin 92 level
of IC3518 set to "H"
on the MC board ?
Yes
MC board failure
(IC3518 or the peripheral
circuit)
Replace the defective part
or the MC board.
BRC-300/300P
BRU-300/300P
One of the following is
defective:
. Power cord
. AC inlet
. Harness between the AC inlet
and the switching power unit
. Harness between the switching
power unit and the MC board.
. Switching power unit
No
Check above in order from the
top to identify the defective part.
c
Be careful. Checking while
applying power may result in
electrical shock.
No
Replace the fuses F4001 to
F4003 on the MC board, and
check the power supply system.
MC board failure
(IC4001 to IC4003, Q4006 to
No
Q4010, T4001, or the peripheral
circuit)
Replace the defective parts or
the MC board.
MC board failure
No
(X3501 or the peripheral circuit)
Replace the defective parts or
the MC board.
MC board failure
No
(IC3502, IC3503, or the
peripheral circuit)
Replace the defective parts or
the MC board.
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