Table of Contents
Baseband Troubleshooting .................................................................................................................................. 3–5
Introduction to BB Troubleshooting ................................................................................................................... 3–5
Non re-workable Baseband Components ........................................................................................................... 3–5
Baseband main troubleshooting......................................................................................................................... 3–5
........................................................................................................................................................................... 3–5
Phone does not power on............................................................................................................................... 3–6
Power supply troubleshooting ....................................................................................................................... 3–6
Clocking system troubleshooting ................................................................................................................... 3–9
Flash programming troubleshooting..........................................................................................................  3–11
Main memory troubleshooting....................................................................................................................  3–12
Charging troubleshooting ............................................................................................................................  3–13
Single SIM card troubleshooting..................................................................................................................  3–15
Dual SIM troubleshooting (only for RM-761) ..............................................................................................  3–17
USB troubleshooting.....................................................................................................................................  3–18
User interface troubleshooting.........................................................................................................................  3–19
Keyboard troubleshooting ...........................................................................................................................  3–19
Display troubleshooting ...............................................................................................................................  3–20
Backlight troubleshooting............................................................................................................................  3–21
Camera interface troubleshooting ...................................................................................................................  3–22
Camera troubleshooting instructions .........................................................................................................  3–22
No valid data from Camera interface IC  .....................................................................................................  3–24
Audio troubleshooting.......................................................................................................................................  3–25
Audio troubleshooting test instructions.....................................................................................................  3–25
Internal microphone troubleshooting........................................................................................................  3–25
Internal earpiece troubleshooting ..............................................................................................................  3–27
IHF speaker troubleshooting........................................................................................................................  3–28
External microphone troubleshooting........................................................................................................  3–29
Headset speaker troubleshooting ...............................................................................................................  3–30
FM radio troubleshooting..................................................................................................................................  3–31
FM radio troubleshooting.............................................................................................................................  3–31
Memory card troubleshooting ..........................................................................................................................  3–32
Cannot detect memory card.........................................................................................................................  3–32
List of Figures
Figure 2 Baseband test point locations .............................................................................................................. 3–5
Listing 1: High current when battery is inserted, I>500mA; ............................................................................ 3–7
Figure 4 High current when battery inserted..................................................................................................... 3–7
Figure 5 IR picture showing component overheat ............................................................................................ 3–7
Listing 2: High current after pressing power-on key, 100mA<I<500mA......................................................... 3–8
Figure 7 High current after pressing power-on key .......................................................................................... 3–8
Figure 8 No current when pressing power on key............................................................................................. 3–9
Figure 9 26 MHz Clock does not work...............................................................................................................  3–10
Figure 10 32 KHz RTC clock does not work ......................................................................................................  3–11
Figure 11 Cannot identify charger....................................................................................................................  3–14
Figure 12 No charging current..........................................................................................................................  3–15
Figure 13 Cannot identify SIM card...................................................................................................................  3–15
Figure 14 SIM voltages, no ATR.........................................................................................................................  3–16
Figure 15 SIM voltages, normal startup at 3V .................................................................................................  3–16
Figure 16 SIM 1 troubleshooting flow..............................................................................................................  3–17
RM-761; RM-799; RM-800
BB Troubleshooting and Manual Tuning Guide
Issue 1 COMPANY CONFIDENTIAL Page 3 – 3
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