Nokia 3806 Service Manual page 101

RM-583
Baseband Description and Troubleshooting
Key components overview .................................................................................................... page 6-5
System block diagram........................................................................................................... page 6-6
Platform Introduction ............................................................................................................ page 6-7
QSC1110........................................................................................................................ page 6-7
Power up....................................................................................................................... page 6-9
Power off..................................................................................................................... page 6-10
Power Distribution ...................................................................................................... page 6-10
Battery .........................................................................................................................page 6-11
Display and keypad ..............................................................................................................page 6-11
Troubleshooting...................................................................................................................page 6-11
Power does not stay on (refer to VREG_OUT circuit) ........................................................... page 6-12
Power does not stay ON troubleshooting .................................................................... page 6-14
PMU circuits................................................................................................................ page 6-14
Audio faults......................................................................................................................... page 6-15
No sound in earpiece & microphone (refer to MIC headset, Audio PA circuit design) ... page 6-15
Audio faults troubleshooting....................................................................................... page 6-15
Display faults ...................................................................................................................... page 6-18
Display faults troubleshooting..................................................................................... page 6-18
Keypad faults (refer to Keypad circuitry) ............................................................................. page 6-19
Keypad faults troubleshooting .................................................................................... page 6-19
Keypad part circuitry................................................................................................... page 6-22
Vibrator faults ..................................................................................................................... page 6-22
No vibration troubleshooting....................................................................................... page 6-22
Vibrator circuit ............................................................................................................ page 6-23
USB interface faults ............................................................................................................ page 6-23
USB Interface disabled troubleshooting ...................................................................... page 6-24
USB circuit.......................................................................................................................... page 6-25
FM faults troubleshooting ................................................................................................... page 6-26
FM circuit ............................................................................................................................ page 6-27
UIM card unreadable troubleshooting.................................................................................. page 6-28
UIM card circuit ................................................................................................................... page 6-29
T-flash card unreadable....................................................................................................... page 6-30
T-flash card circuit .............................................................................................................. page 6-31
Camera unreadable ............................................................................................................. page 6-32
Camera circuit..................................................................................................................... page 6-33
Charging faults troubleshooting.......................................................................................... page 6-34
Issue 1
Table of Contents
COMPANY CONFIDENTIAL
Copyright © 2009 Nokia. All rights reserved.
Page 6-3