1. Training for ALT
10 30, 2014
YJ / Terry

2. BB Component Placement- MB (Top)

3. BB Component Placement- MB (Bottom)

4. BB Component Placement- ANT/B (Top)

5. BB Component Placement- ANT/B (Bottom)

6. Function block

7. Power Sequences

8. Power on regulator sequencing

9. BB issue list Can’t power(big current) Can’t enter system
No display after display flashs
Power off current Fail
Can’t charge
Can’t recognize USB
Can’t recognize SD
KEY no function
Rear/front camera are fail
LCD/TP no function
earphone或Speaker no function
MIC no function

10. Can’t power(big current)
Check all power planes for shorts to ground or to each other
Check Polarity
Check whether have the wrong components
Check components whether was damaged
Check X-Ray

11. EX1:
238: C1650 was wrong VREG_L17_2P9 then was short with GND.

12. EX2:
173: U2400 was reverse

13. EX3:
215: R3102 & C3107 short, B1805 was short).

14. EX4:
458/374/420/393/256 : Shielding shift short

15. EX5:
660 : U601 short

16. EX6:
375 : R605 was air welding

17. Can’t enter system
469 : U4001 damage

18. No display after display flashed
233 : R1503 wrong

19. Power off current Fail
210 : R2410 shortage

20. Can’t charge(Charger Current Fail)

21. Can’t recognize USB check USB connector check USB circuit
Check Fuse_5V (F2300)
Measure per electric meter
Use Diode measure (ID、D+ 、D- ) impedance then compare with good board
Traces whether was connection
Check USB D+ 、D- path B2300 &R1715 & R1716 0R whether was air welding .
Check USB_VBUS_IN_PMIC whether have voltage output 4.5V

22. USB schematics

23. Can’t recognize SD 1.Check polarity and whether have air wielding
2.use electric meter to make sure the path is connection with connector.
3.insert SD card to measure the related electric current.
(R1724 Pu-H 1V8 / VREG_L5_1P8/ VREG_L11_SDC/
VLDO_SD_3V /VREG_L12_SDC)
4. the related current of SD_LDO (VPH_PWR / VREG_L5_1P8/ VREG_L11_SDC)

24. KEY no function 1.Check polarity and whether have air wielding
2.use electric meter to make sure the path is connection.

25. Rear/front camera are fail
Check U803, U1601, J1600
Check Power : VREG_L10_2P8_AF, VREG_L6_1P8,VREG_L17_2P9, CAM_DVDD-1P
Check the back camera was complete to assembly
Check the back camera was good.

26. The circuit of back camera

27. Front camera was fail Check U802, J1602 Check Power:
VREG_L6_1P8,VREG_L17_2P9
Check the front camera was complete to assembly
Check the front camera was good.

28. The circuit of front camera

29. LCD/TP was fail LCD/TP was fail
Check LCD/TP whether are complete to assemble
Check whether was caused by raw material
Check U1501,U1502,U1500,L1500,J1500
LCD don’t light
Check the voltage of VREG_L17_2P9,VREG_L6_1P8,LED+TP
Check the voltage of VREG_L16_UIM3

30. Earphone or Speaker was fail
Earphone was fail
Check J1800,B1801,B1802,B1803,R1812
Check whether have assembly issue
Speaker was fail
Check B502,B505,J2000
Check the sub board of J100,J102,B100,B101
Check FPC
Check whether Speaker have assembly issue

31. MIC was fail Main and Sub MIC no sound Check U1800，U100
Main MIC was fail
Check J100,U100,R100 of sub board
Check FPC
Check CDC_MIC_BIAS1whether have voltage
Sub MIC was fail
Check U1800,R1818
Check the voltage of CDC_MIC_BIAS1

32. Main MIC test fail
Check the rubber on Main MIC Rubber whether was complete cover.
Check the Mesh
Sub MIC test fail