NEC MultiSync 20WGX2 Service Manual page 105

11.2 Connection 11.2 Connection A A pparatus is n n pparatus is
Is it aware of the USB hub in Is it aware of the USB
the host PC? the host PC?
OK OK
Is apparatus connected to the Is apparatus connected to the
down stream port ? down stream port ?
OK OK
Is 5V +/- 5% supplied to P305 Is 5V +/- 5% supplied to P305
pin1 ? pin1 ?
OK OK
Does L302, L303 open ? Does L302, L303 open ?
OK OK
Proceed "12.4 Check the USB IC" Proceed "12.4 Check the USB IC"
section. section.
o o t t R R e cognize ecognize
hub in NG NG
NG NG
NG NG Does 5V output from I309 pin 5 Does 5V output from I309 pin 5
Failure point Failure point
N N G G
L302, L303 L302, L303
failure. failure.
Does 5V output to VBUS1 and Does 5V output to VBUS1 and
I307 power switch failure. I307 power switch failure.
Proceed section 12.1 "HUB isn't recognize" Proceed section 12.1 "HUB isn't recognize"
Failure point Failure point
The un-connection of the down stream port The un-connection of the down stream port
cable. cable.
NG NG
and pin 8? and pin 8?
OK OK
N N G G
VBUS2? VBUS2?
OK OK
Failure point Failure point
6 - 14 6 - 14
Does I309 during Does I309 during NG NG
protection mode? protection mode?
OK OK
Failure point Failure point
Faulty operation of the over- Faulty operation of the over-
current protection function . current protection function .
Failure point Failure point
FB316, FB317 failure. FB316, FB317 failure.
Failure Failure
point point
I309 I309