Sony HT-ST9 Service Manual page 55

4. Power is not turned on (OLED display does not appear)
Power is not turned on.
(OLED display does not appear)
Yes
The voltage of the following is 28 V.
POWER board: CN904 pin 3 to 5
The voltage of the following is
12 to 18 V.
POWER board: CN904 pin 9
Yes
The voltage of the following is 3.3 V.
MB1406 board: IC3004 pin 1, 46
Yes
Vibrator (X3001) on the MB1406
board is oscillated after AC input.
Yes
The reset signal is inputted to pin
49 of IC3004 on the MB1406 board
after AC input.
Yes
The voltage of the following is 3.3 V.
MB1406 board: IC3004 pin 11
(PCONT_FL (O-LED))
Yes
The voltage of the following is 12 V.
MB1406 board: IC303 pin 1
Yes
Check and repair the DISPLAY
board.
No
Fuse (F901) on the POWER board
conduct the electricity.
Yes
Fusible resistor (R914) on the
POWER board conduct the
electricity.
Yes
Replace the POWER board.
Check the IC304 and surrounding
No
circuit on the MB1406 board, and
replace the MB1406 board.
Check the IC3004 or state of
No
vibrator (X3001) on the MB1406
board, and replace the MB1406
board.
Check the IC3005 and surrounding
No
circuit on the MB1406 board, and
replace the MB1406 board.
Check the state of IC3004 on the
No
MB1406 board, and replace the
MB1406 board.
Check the IC303 and surrounding
No
circuit on the MB1406 board, and
replace the MB1406 board.
No
Replace the fuse (F901) on the
POWER board.
No
Replace the fusible resistor (R914),
IC930 on the POWER board.
HT-ST9
55