Sony BDP-S485 Service Manual page 120

USB (Front) Device Flow
USB device is not recognized
No
Insert the USB device again.
Is 5V present at
Is it recognized when the power is
board) pin1?
turned OFF and then ON again?
Yes
Poor contact of the USB device
Replace the FFC between the
MB board and the FR board.
Do the symptoms improve?
Defective FFC between the IF
board and the MB board
CN201(FR-313
Is 5V present at IC601
No
(MB board) Pin 5 ?
Yes Yes
Defective FFC between the FR
board and the MB board.
No Replace the MB board.
Yes
Is 6V present at C601pin8
No No
(MB board)?
Yes
Does replacing IC601(MB board)
No
improve the symptoms?
Yes
IC602(MB board) defective
Power supply IC310 (MB board -
defective
Replace the MB board