Nokia 6235 Guide

Nokia Customer Care
6235/6235i/6236i (RM-60)
Mobile Terminals
Issue 1 04/2005 Company Confidential ©2005 Nokia Corporation
Baseband Description and
Troubleshooting

6235/6235i/6236i (RM-60)
Baseband Description and Troubleshooting
Page 2 ©2005 Nokia Corporation Company Confidential Issue 1 04/2005
Contents Page
Introduction ..................................................................................................................................................... 5
Power Up Sequence ....................................................................................................................................... 7
Flash Programming ........................................................................................................................................ 8
Flashing Tool .................................................................................................................................................8
Flashing Phoenix Interface .......................................................................................................................9
Audio.................................................................................................................................................................. 9
How the Audio Works ................................................................................................................................9
Audio Troubleshooting .............................................................................................................................10
Audio Phoenix Interface ..........................................................................................................................12
Camera............................................................................................................................................................ 12
How the Camera Works ...........................................................................................................................12
Camera Troubleshooting ..........................................................................................................................13
Camera Phoenix Interface .......................................................................................................................14
FM Radio ........................................................................................................................................................ 15
How the FM Radio Works .......................................................................................................................15
FM Radio Test .............................................................................................................................................15
FM Radio Troubleshooting ......................................................................................................................15
FM Radio Phoenix Interface ...................................................................................................................16
USB (Universal Serial Bus)......................................................................................................................... 17
How USB Interface Works .......................................................................................................................17
USB Troubleshooting ................................................................................................................................18
USB Phoenix Interface .............................................................................................................................20
Display ............................................................................................................................................................ 21
How the Display Works ............................................................................................................................21
Display Troubleshooting ..........................................................................................................................21
Display Backlight Troubleshooting .......................................................................................................22
Display Phoenix Interface .......................................................................................................................24
Keypad Backlight ......................................................................................................................................... 24
How the Keypad Backlight Works ........................................................................................................24
Keypad Backlight Troubleshooting .......................................................................................................25
Keypad Backlight Display Phoenix Interface .....................................................................................27
GPS................................................................................................................................................................... 27
How GPS Works .........................................................................................................................................27
GPS Troubleshooting ................................................................................................................................28
GPS Phoenix Interface ..............................................................................................................................31
SIM Card......................................................................................................................................................... 31
How SIM Card Works ...............................................................................................................................31
SIM Card Troubleshooting ......................................................................................................................32
Sim Card Phoenix Interface ....................................................................................................................35
Infrared........................................................................................................................................................... 35
How Infrared Works ..................................................................................................................................35
Infrared Troubleshooting .........................................................................................................................36
Infrared Phoenix Interface ......................................................................................................................37
System Connector........................................................................................................................................ 38
Accessory Detection.................................................................................................................................... 39
Battery (Lynx) Interface Circuit............................................................................................................... 40
PWB Overview .............................................................................................................................................. 41

Nokia Customer Care Baseband Description and Troubleshooting
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Bottom Board .............................................................................................................................................41
Top Board .....................................................................................................................................................42
Main Test Points .......................................................................................................................................... 43
Current Test Points ....................................................................................................................................43
Current too High at Zero Test ................................................................................................................43
Terminal in Local Mode Test ...................................................................................................................44
Display Test .................................................................................................................................................45
Charging Test ..............................................................................................................................................45
Common Problems ...................................................................................................................................... 46
No Communication During Flash ..........................................................................................................46
No Communication During Alignment ................................................................................................46
Failed Self Test/Calibrate .........................................................................................................................47
Phone Not Powering Up ..........................................................................................................................47
Shut Down After 32 Seconds .................................................................................................................47
No Audio ......................................................................................................................................................47
Key Pads Malfunction ..............................................................................................................................47
No LCD Display ...........................................................................................................................................48

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Baseband Description and Troubleshooting Nokia Customer Care
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Nokia Customer Care Baseband Description and Troubleshooting
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Issue 1 04/2005 ©2005 Nokia Corporation Company Confidential Page 5
Introduction
The 6235/6235i/6236i baseband module is a tri-mode, Code Division Multiple Access
(CDMA), dual-band engine and is based on the DCT4.5 standard. The baseband engine
includes two major Application Specific Integrated Circuits (ASICs):
• D2200 or UEMEK 2VO — Universal Energy Management Enhanced Integrated
Circuit (UEME IC), which includes the audio circuits, charge control, and voltage
regulators
• D2800 or TIKUEDGE v1.1 — Main mobile terminal processor, which includes
system logic for CDMA, two Digital Signal Processors (DSPs), the Main Control
Unit (MCU), and the memory
The BL-6C Li-ion battery is used as the main power source and has a nominal capacity of
1070 mA/h.

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Figure 1: Baseband block diagram
Even though the Bluetooth, External Display and MMC components are on the ASICs,
they are not used in the 6235/6235i/6236i baseband module.
PWM
Parallel
Battery Zocus
Sim MMC
D2800
MCU ARM925
PDRAM
C-DSP Lead3
A-DSP Lead 3
2G System Logic
D2200
Regulation
Charge Control
Audio
FBUS / MBUS
SIM I/F
RTC
Tomahawk
DC Jack
Int Display
Production
Test IF
RF
Keyboard
Mic
IHF Speaker
Disp BL’s
Camera
IRDA
Bluetooth
FM Radio
Antenna
SMPS
SDRAM
CBUS
Nut
USB
PCM / UART
VCORE
VIO
Regulator
Serial
Ext Display
UHS Jack
EL
Amplifier
EarPiece
Vibra
Cam Flash
PWM
Flash Memory
(Program,
NOR)
Flash Memory
(User, NAND)
D
B
U
S
32 KHz
GPS
19.2 MHz
UART

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Power Up Sequence
When phone is dead or jammed always check the Power Up Sequence of the baseband
area. Verify all regulator and reset signals are correct to ensure proper power up of
UEMEK and D2800 (see Figure 2).
Figure 2: Power-on sequence and timing
Reference signal
PwrOnX
Charger Detection
RTC
UEMRSTX
VCORE
VFlash1
VIO
VANA
VR3
19.2MHz Clk
PURX
t1 t2 t4t3
Sleep Clock
t1 = 20ms
t2 = 200ms
t3 = 500us
t4 = 20ms
Reset mode is entered and
the watchdog starts
End of settling time (only if Vbat > Vcoff+_);
VFLASH1 regulator enabled
VR3, VANA, VIO, and VCORE enabled;
PURX held LOW
D2800 processor, MCU, and DSP are
reset; VCTCXO regulator forced on

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Figure 3: Power Up Sequence
Flash Programming
Flashing Tool
Figure 4 shows the DA-54 flashing tool.
Figure 4: DA-54 Flashing Tool

Nokia Customer Care Baseband Description and Troubleshooting
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Flashing Phoenix Interface
Run EZ Flash in Phoenix to flash the phone.
Figure 5: EZ Flash in Phoenix
Audio
How the Audio Works
The baseband supports three microphone inputs and two earpiece outputs. The
microphone inputs are MIC1, MIC2, and MIC3:
• MIC1 input is used for the phone's internal microphone,
• MIC2 input is used for headsets (HDB-4),
• MIC3 input is used for the Universal Headset.
Every microphone input can have either a differential or single ended ac connection to
UEMEK circuit. In the Nokia 6235/6235i/6236i, the internal microphone MIC1 and
external microphone MIC2 for Pop-Part™ accessory detection are both differential.
However, the Universal Headset interface is single ended. The microphone signals from
different sources are connected to separate inputs at UEMEK. Inputs for the microphone

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signals are differential type. Also, MICB1 is used for MIC1 and MICB2 is used for MIC2
and MIC3 (Universal Headset).
Figure 6: Audio components
Audio Troubleshooting
When troubleshooting the audio, make these common checks (see Figure 7):
• Performed visual inspection of all the ASIP’s and UEMEK
• Inject 1KHz signal into MiC1 and trace it all the way to the ear piece. Only when
using IHF signal will be amplify by a factor of 8.
UHJ MIC3
IHF
MIC2 MIC1
Ear Piece

Nokia Customer Care Baseband Description and Troubleshooting
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Figure 7: UEMEK Side of Audio Diagram
Audio Amplifier
Audio ASIP’s
FM Radio Lines DC Block Caps
Audio ASIP’s
UHJ
MIC3
MIC2
MIC1
Ear Piece
IHF

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Audio Phoenix Interface
Run Audio Test in Phoenix to check the audio functionality.
Figure 8: Audio Test in Phoenix
Camera
How the Camera Works
When you select the view finder to take a picture, the D2800 activates the camera by
turning on GENIO(27) and GENIO(24)9.6MHz. Once the camera is initialized, D2800
sends control commands through the I2C (GENIO (25&26) interface. The camera takes a
MiC1- Use first option to route the audio from the
internal microphone to the headset speaker.
MiC2- Use second option to route the audio signal
from the headset microphone to internal ear piece.
MiC3 - To test MIC3 you need to use the first and
second options. Open channel and insert the
universal headset. The UEM automatically re-routes
the audio signal to the UHJ.
Ear Piece - Use second option to hear something
from internal ear piece.
IHF - Use the fifth option to route audio signal to IHF
speaker out.

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picture and sends data back to D2800 for processing through CCP lines. After D2800
finishes with all image processing, the image is stored in the flash memory.
Figure 9: Camera and HWA connections to the baseband
Camera Troubleshooting
When troubleshooting the camera, make these common checks (see Figure 13):
• Check Power Supply V2.8 and VDIG
• Check Sleepx is high
• Camera Enable GenIO(27) is high
• Check Camera Clk on GenIO(24)
• Check Control line I2C on GenIO 25& 26
• Check raw data lines going back to D2800
• Inspect camera socket and replace Camera
• Check D2800 for Solder problems and replace, if necessary

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Figure 10: Camera socket and checkpoints
Camera Phoenix Interface
Run Camera Contol in Phoenix to check the camera functionality.
V 2.8V
GENIO(27) (EN)
GENIO(24) (9.6Mhz)
GENIO(25)
GENIO(26)
Raw Image Data
VDIG 1.8V
Camera socket inspection
Use Viewfinder On option to view image
in the PC Window
Camera with integrated VGA camera and
camcorder functionality

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Figure 11: Camera Control in Phoenix
FM Radio
How the FM Radio Works
D2800 turns on the FM radio and sets the frequency using CBUS serial interface as the
communication channel. A high frequency FM radio signal come in through RFIN1 Pin to
the FM radio chip, then it gets demodulated into a low frequency signal and send to
UEMEK for amplification. The amplify signal then get routed back to either universal
headset or to the system connector for stereo headset.
Figure 12: FM Radio (N356), Audio (N150), antenna, and digital interface connections
FM Radio Test
To hear the FM radio, you first connect headset to Pop-Part™ or UHJ ports because the
headset will be an FM radio antenna. And you have to connect headset to UHJ port to
control the FM radio by using Phoenix. But if you connect a headset (such as HDS-3) to
Pop-Part™ connector, then you can’t control the phone because you’ve already occupied
the connection port (Pop-Part™), so in this case you have to have jumper wires on
production test points (Fbus Tx/RX,GND).
FM Radio Troubleshooting
When troubleshooting the FM radio, make these common checks (see Figure 13):
• Check Power Supply VIO and VANA
• Check SleepCLK
• Check FMANT
• Check for activity on CBUS
• Check output of FM radio on VAFR and VAFL
• If 6 is not correct, then Check FM radio chip for shorts, voids, and misalignments

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• If 6 is correct, then Check EUMEK for shorts, voids, and misalignments
• If UEMEK and FM Radio Chip is correct, then check system connector
Figure 13: FM Radio Chip and Antenna
FM Radio Phoenix Interface
Checks for the FM radio that you can do with Phoenix include:
• Verify FM radio is working by connecting Headset to UHJ
• Turn on FM radio
• Set frequency and volume
• If FM radio is working then, retest on FinalUI
FM Radio Chip (always
the check solder)
FMANT
VAFLVAFR
VANA (2.8V)
VIO (1.8V)
XEAR_LP
XEARN
FMANT
GND

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Figure 14: Phoenix FM Radio Control panel
USB (Universal Serial Bus)
How USB Interface Works
When Phone connects to a computer using a DKU-2 data cable the computer will
provide Vbus (5V) to and pull down D+ a,d D – lines. The phone will respond by pulling
the D+ line high. The computer acknowledges and start transferring data at 12Mbits/sec.
Power On check box
Frequency control
Volume control

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Figure 15: USB interface block diagram
USB Troubleshooting
First connect phone to computer using a DKU-2 data cable. Check under device manager
to see if the computer recognizes the phone as a USB device. If the phone is recognizes,
there is no hardware fault and you can stop troubleshooting.
Figure 16: PC Device Manager
When troubleshooting UPS, make these common checks (see Figure 29 and Figure 30):
• Perform visual inspection on Pop-Part™ connector, ESD Protection, NUT Chip, and
caps and Inductors

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• Check Vout, Vflash1, and ACI Line. If not correct, check UEMEK under X-ray or
change part.
• Check for activity on the USB D+ and USB D – lines, if nothing check D2800
under X-ray or change part.
Figure 17: USB Chip and Diagram
USB Vbus (5V)
Vout
USD ESD Protection
ACI
_OE (1.8V)
USB D+ (3.3V)
USB D- (3.3V)
USB D+
USB D-
VFlash1 (2.8V)

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Figure 18: USB Vout
USB Phoenix Interface
Run the USB Tests in Phoenix to check the USB functionality:
Figure 19: USB Phoenix Interface