Nokia NEM-4 Series Troubleshooting Instructions page 138

NEM-4
RF Troubleshooting
BT Failure
Part III
(BER Failure)
Check VCC
(Pins 52, 53, 54)
with O-scope
Does VCC =
2.95 - 5.2
VDC?
Yes
No
Does Ripple
Voltage
< = 400mVpp?
Yes
Check VREG
(Pin 6)
with O-scope
Does VREG =
2.9
2.7 - 3.3 VDC?
Yes
No
Does Ripple
Voltage
< = 30mVpp?
Yes
Yes
Check VBBEN (Pin49)
with O-scope
Does VBBEN
No
1.4 - 4.0 VDC?
Ýes
Page 6(b)-134
Company Confidential
No
Check
L431 /
VBAT / L430 /
C431
No
Check
L430/
VFLASH1 / L431
C432
Check VEMRST / R436
UEMRST
Copyright  2003 Nokia Corporation.
Company Confidential
CCS Technical Documentation
Check SYSCLCK
(Pin 50 )
with O-scope
Does Vin =
300-800
300-900mVpp?
Yes
No
Does Freq. =
26MHz?
Yes
Can you make
Is BER < =
a connection to Yes
0.1%?
BT Box?
No
1) Replace
BT MCM
2) Flash Phone
BT OK!
using 'BT ONLY'
No
Check
VCTCXO
Buffer Section
1) Replace
BT MCM
No 2) Flash Phone
using 'BT ONLY'
Yes
Issue 1 09/2003