User Guide

RH-21 Company Confidential
Troubleshooting Nokia Customer Care
Page 6  2004 Nokia Corporation. Issue 2 07/2004
Troubleshooting
Note: Most of the baseband repair actions require removing the baseband shield. The shield must not
be removed unless separately authorized by the program.
Note: The phone’s ESN has to re-written to the UEM, if the UEM is replaced. This can be done only in
Central Service.
The baseband troubleshooting instructions include the following topics:
1Power up
2 Flash programming
3Audio
•Earpiece
•Microphone
4 Charging
5 Accessory detection
6 Sleep clock
7 User interface
•Display
•Lights
•MIDI
•Vibra
• Keyboard
Power-up faults
Power-up sequence
1 The UEM acts as a HW master during start up
• Vbatt limits: 2.1V for internal state machine, 3V triggering whole startup
• Regulator sequencing
• HW "core" regulators "on": Vio, Vcore, VR3, Vflash1
• These regulators supply the processors, memory chip interfaces and clock source
in RF
• Reset releasing delay