MiTAC 7521 PLUS/N User Manual

124

An error occurs when a USB I/O device is installed.

USB TEST ERROR

1. Check if the USB device is 

installed  properly.

2. Confirm USB driver is installed 

ok.

Test

OK?

Re-test

OK?

Change M/B or go
into board-level
Troubleshooting.

YES

NO

Correct It.

YES

NO

Change the
faulty part
then end.

Board-level

Troubleshooting for

USB test error

Check the following parts for cold solder or one of the following 
parts on the mother-board may be defective, use an oscilloscope
to check the following signal or replace the parts one at a time and 
test after each replacement.

Parts:

U24, RP21, CP7
F502, R20, R19
C506, L2, C14
F503, R22, R23
C507, L6, C25
R141, R140, R142
R143, , L12
L8, L504, L511

Signals:

USBP1-

USB_B1

USBP1+      USB_B2
USBP0-

USB_B3

USBP0+      USB_B4
D/USBP1- USB_A1 
D/USBP1+  USB_A2
D/USBP0- USB_A3 
D/USBP0+  USB_A4
USB_OC0#
USB_OC1#

Try another known
good USB device.