NEC MultiSync 20WGX2 Service Manual page 104

1 1 1. Check the 1. Check the USB Hub Circuit USB Hub Circuit
11.1 HUB is n n 11.1 HUB is o o t t R R e congnize econgnize
Is a cable with the host PC connected Is a cable with the host PC connected
Is a USB cable connected with the Is a USB cable connected with the
monitor? monitor?
Is a 3.3V supplied to I319 Vcc Pin 3, 7, 11, Is a 3.3V supplied to I319 Vcc Pin 3, 7, 11,
15, 19, 23, 27, 33, 39, 45, 55 ? 15, 19, 23, 27, 33, 39, 45, 55 ?
Is a Reset Signal Input to Is a Reset Signal Input to
I319 pin 46? I319 pin 46?
Doesn't clock input to Doesn't clock input to
I319 pin 21. I319 pin 21.
Proceed "12.4 Check the USB IC " Proceed "12.4 Check the USB IC "
section section
OK OK
OK OK
OK OK
NG NG
R434, R433, C499, R434, R433, C499,
OK OK
NG NG
OK OK
Printed wire breaks Printed wire breaks
between X302 and between X302 and
Failure point Failure point
NG NG
USB cable disconnection USB cable disconnection
Failure point Failure point
NG NG
USB cable disconnection USB cable disconnection
Doesn't I306 open Doesn't I306 open
NG NG
Failure point Failure point
D331. D331.
Failure point Failure point
X302 X302
OK OK
I308 I308
6 - 13 6 - 13
Failure point Failure point
NG NG
I306 I306