Usb Problems (2) - Nokia RM-12 Troubleshooting Instructions

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USB Problems (2)

Continued from
USB
troubleshooting
page 1
Measure
resistance to GND
from D+(pin #6)
and D-(pin #7) on
X2021 .
>> 1M?
Yes
Check APE
GPIO3 from No
R2004, ~2.8V
No, but
APE GPIO3
Yes
~V28
Measure
voltage V33 at
C2005
Incorrect
voltage
Measure
voltage VBUS
Incorrect
at C2006 when
voltage
connecting the
USB cable
~5V
Change USB
regulator N2001
and capacitors
C2005-C2007 and
resistor R2004
Issue 1 11/2004
Check R2004
value.
Damaged
Change
resistor. PC No,
recognizes the APE GPIO3
phone as USB still 0V
device?
Yes
End
Correct voltage
Change L2002,
PC recognizes
No
the phone as
USB device?
Yes
End
Measure
USB+ (pin #6)
PC recognizes
and USB- (pin
No
the phone as
#7) on X2021
USB device?
with
oscilloscope
Yes
End
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Undamaged
No
Go to OMAP1510
troubleshooting
Voltage levels
~0V and
~3.3V
Replace
EMI filter R2003
No
PC recognizes the
toggling
phone as USB
device?
No
Go to OMAP1510
Toggling
troubleshooting
RM-12
Yes End
Page 94