Connection Apparatus Is Not Recognize - NEC MultiSync 20WGX2 Series Service Manual

11.2 Connection Apparatus is not Recognize

Is it aware of the USB hub in
the host PC?
OK
Is apparatus connected to the
down stream port ?
OK
Is 5V +/- 5% supplied to P305
pin1 ?
OK
Does L302, L303 open ?
OK
Proceed "12.4 Check the USB IC"
section.
NG
Proceed section 12.1 "HUB isn't recognize"
NG
The un-connection of the down stream port
NG Does 5V output from I309 pin 5
and pin 8?
Failure point
OK
L302, L303
failure.
Does 5V output to VBUS1 and
VBUS2?
OK
Failure point
I307 power switch failure.
6 - 14
Failure point
cable.
NG Does I309 during
protection mode?
OK
Failure point
Faulty operation of the over-
current protection function .
Failure point
FB316, FB317 failure.
Failure
point
NG
I309