1. 4.3 Logic Part Trouble 4.3.1 Power 4.3.1.1 Power-On Trouble
Circuit Diagram
MAIN PCB
+2.9V_ RX0
+2.8V_ TCXO
+2.6V_ MSMA
U400
+2.6V_ MSMP2
+1.4V_ MSMC
+1.8V_ MSMP1

2. Checking Flow START YES NO Check Battery Voltage > 3.4V ?
Charge of Change Battery and try again
YES
Push power-on key and check
the level change of
U400 ON_SW/ NO
Check the contact of power-key
or dome switch
YES
Check the voltage
Level of the following port at U400
+1.375V_MSMC
+2.6V_MSMP2
+1.8V_MSMP1
+2.6V_MSMA
+2.8V_TCXO
+2.9V_RX0 NO
Replace the U400
YES
The logic level at PS_HOLD(R402) of U400 = High ? NO
Re-download software & try again
YES
Does it work properly?
Does it work properly? NO NO
The power-on procedure is completed.
The problem may be elsewhere.
YES
The Phone will power on.
Replace the main board.

3. 4.3.1.2 Charging Trouble Circuit Diagram Test Points MAIN PCB Q404
+V_PM

4. Checking Flow
SETTING : Connect the battery and the charging adaptor (TA) to the phone
START
YES NO
Voltage at +V_CHAR
of Q401 = 4.8V?
The charging adaptor (TA) is out of order.
Change the charging adaptor.
YES NO
Voltage at Q404 = 4.8V?
Replace Q401, Q402
YES
Voltage at +V_PM
of Q405 = 4.2V? NO
Replace Q404
YES
The logic level at BATT_FET/
of Q405 = Low? NO
Replace Q405
YES
Is the battery
charged NO
The battery may have the problem
Change the battery and try again.
YES
Charging will operate properly

5. 4.3.2 LCD 4.3.2.1 LCD Trouble Circuit Diagram MAIN PCB Test Points
• LCD Control signals
From MSM : D2[0:15], LCD_REST/, LCD_CS/, WE2/, A2[7]
• Check point
- The assembly status of the LCD Module
- The Soldering of connector
MAIN PCB
Test Points
CON600
+2.8V_LCD
MAIN PCB
SUBPCB
U402
Coaxial Cable
F103
F102
F101
F100
CON100
CON101

6. Check CON600,CON100 soldering
Checking Flow
START
Yes
Voltage at +2.8V_LCD
of U402 = 2.8V? No
Replace U402
Yes
; Check F100, F101, F102, F103
Check the
Control signal
D2[0:15], RESET/,
LCD_CS/, WE2/,A2[7] No
Replace Coaxial Cable
Yes
Check CON600,CON100 soldering No
Re-solder CON600 ,CON100
Yes
Check CON101 soldering No
Re-solder CON101
Yes
Change the LCD Module

7. 4.3.3 Camera 4.3.3.1 Camera Trouble Circuit Diagram
• Camera Control signals
From MSM : CAM_DATA[0:7], CAM_RESET/, CAM_SDA, CAM_SCL,
CAM_CLK, CAM_PCLK

8. Test Points MAIN PCB • Check point
- The assembly status of the Camera Module
- The Connection of connector
MAIN PCB
+2.6V_ CAMA
+2.6V_ CAMIO
U400
R528
F500
R529
F501
CON502
R536
C519
X500

9. Checking Flow START Check the clock to Camera at R536 (48MHz) No
Replace X400
Yes
Check the clock from Camera
at C519 : CAM_PCLK No
Replace the Camera module assay
Yes
Check the voltage
Level of the following port at U400
+2.6V_CAMA +2.6V_CAMIO No
Replace U400
Yes
Check the
Control signal
CAM_DATA[0:7], CAM_RESET/,
CAM_SDA, CAM_SCL
; Check F500, F501,R528,R529
Yes
Check CON502 soldering No
Re-solder CON502
Yes
Camera will
work properly

10. 4.3.4 Audio 4.3.4.1 Speaker Trouble Circuit Diagram Test Points
MAIN PCB
CON502
R525
R524
U302
U305
C315
C314
L300

11. Checking Flow SETTING : “Melody on” at sounds of test menu. START
Voltage at L300
Is about 3.4~4.2V NO
Replace L300
Yes
Check the audio signal at
C314, C315 NO
Check the Soldering of
C314, C315 NO
Replace U305
Yes
Yes
Re-solder C314, C315
Check the audio signal at
R524 ,R525 NO
Check the Soldering of
R524 ,R525 NO
Replace U302
Yes
Yes
Re-solder R524 ,R525
Check the state
Of contact of CON502 NO
Reconnect Camera ASSAY
Yes
Check the state
Of contact of speaker NO
Replace Speaker
Yes
Speaker will work properly

12. 4.3.4.2 Receiver Trouble Circuit Diagram Test Points MAIN PCB MAIN PCB
CON600
MAIN PCB
SUBPCB
U305
R336
R106 R107
Coaxial Cable
CON100

13. Checking Flow START Check the audio signal at R335, R336 NO
Check the Soldering of
R335, R336 NO
Replace U305
Yes
Yes
Re-solder R335, R336
Check the audio signal at
R106, R107 NO
Check the Soldering of
CON600 ,CON100
and Connection of Coaxial Cable NO
Replace CON600 ,CON100,
Coaxial Cable
Yes
Yes
Re-solder CON600 ,CON100
Check the state
Of contact of receiver NO
Replace Receiver
Yes
Receiver will work properly

14. 4.3.4.4 Headset Trouble Circuit Diagram MAIN PCB Test Points MAIN PCB
CON604
R338
R331
U304
MAIN PCB
U303
R339

15. Headset detect problem Headset sending path problem
Checking Flow
START
Insert the headset to the handset.
Yes
Headset detect problem
Does the audio
Profile of the phone change to
the headset mode? No 1
Yes
Set the audio part of the test
equipment to echo mode
Set the audio part of the
test equipment to
continuous wave mode
Can you hear your voice
from the headset?
Headset receiving
Path problem No
Change the headset and
try again.
Yes
Can you hear the sound
from the headset? No 2 No
Can you hear your voice
from the headset?
Yes
Yes
Headset sending path problem 4 3
The headset will
work properly
Headset receiving path problem 2
Check the audio signal at
R338, R339 No
Download
S/W
Yes
Check soldering of
Pin2,3 of CON604 No
Replace U304
Yes
Change
main board

16. Headset detect problem1
Headset detect
problem
Level of pin4 of CON604
Is 1.65~2.10V?
Check soldering R331 No No
Yes
Yes
Re-solder R331
Check soldering
U304 No
Re-solder U304
Yes
Level of
EAR_JACK_SENSE/
Is low? No
Download SW
Yes 4
Headset sending path problem
Headset sending
path problem 3
Level of pin4 of CON604
Is 1.65~2.10V? No
Re-solder
R331
Yes
Does it work? No
Download SW
Yes
Does it work well? No
Change CON604
Yes 4

17. Mic Trouble
Circuit Diagram
Test Points
R117
M100
KEY PCB
R125

18. SETTING : After initialize 5515C, Test Cellular
Checking Flow
SETTING : After initialize 5515C, Test Cellular
START
Check the voltage level
at R213 is 1.0~2.0V No
Check the soldering
Of R213 No
Re-solder R213
Yes
Yes
Check the signal level
at each side of MIC.
Replace MSM No
Replace the microphone
Yes
Check the soldering at VR117, VR125 No
Re-soldering
R117, R125
Yes
Check the soldering of
MIC NETWORK No
Re-solder MIC NETWORK
Yes
MIC will work properly

19. 4.3.6 Vibrator, Mini SD Detect, and USB Interface
Circuit Diagram
Test Points
KEY PCB
Q100
R102
R103
R101
Q102

20. Is the voltage of MOTOR_EN
Checking Flow
SETTING : “Vibrator on” at Sounds of test menu
START
Is the voltage of MOTOR_EN
about 2.6V ? No
Change the main board
Yes
Check soldering of R101,
R102, R103 No
Re-solder R101, R102, R103
Yes
Is Q100, Q102
Working? No
Replace Q100, Q102
Yes
Check the state at
Contact of Vibrator No
Re-contact vibrator
Yes
Replace Vibrator
Yes
The vibrator will
Work properly

21. 4.3.6.2 Micro SD Detect Circuit Diagram Test Points MAIN PCB KEY PCB
CON101
MAIN PCB
KEY PCB
PIN 1
U400
PIN 2
PIN 3
PIN 4
PIN 5
PIN 7
PIN 8
PIN 9
+3.0V_ SD

22. Checking Flow SETTING : Insert the mini SD card into the phone START
Level of SD_DETECT at PIN 9
of CON101 is ‘High’ ? No
Check the soldering of CON101
Yes
Level of +3.0V_SD at U400
is 3.0V ? No
Replace U400
Yes
Levels of SD_CMD(PIN3 of CON101)
and SD_DATA[0]~DATA[3](CON101)
are ‘High’ ? No
Reconnect CON102
Yes
Access a file in the micro SD
; play music or view a PIX/FLIX
Frequency of SD_CLK(PIN5
of CON300) is about
9.6MHz ? No
Replace the main board
Yes
THE MINI SD CARD WILL BE DETECTED

23. 4.3.6.3 USB Interface Circuit Diagram Test Points MAIN PCB Q407
X200 R200
D402

24. Checking Flow START YES NO Level of VBUS at D402 is 5.0V ?
Check the connecting of the data cable
YES
Check the voltage of the following
port at Q407
USB_POWER=5V?
Check the soldering Q407 NO NO
Replace Q407
YES
YES
Re-soldering
Q407
The Frequency at X200 is 48 MHz? NO
Check the soldering X200,R200 NO
Replace
X200,R200
YES
YES
Re-soldering X200,R200
Check the voltage level at R551
Is it almost 3.3V? NO NO
Check the soldering
R551,R552
Replace U400
YES
YES
Re-soldering
R551,R552
THE USB INTERFACE WILL WORK PROPERLY