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ASUS T500                                            MB Service Manual 

   

 

 

Content 

I. Baseband Troubleshooting Guide 

1. System Block Diagram   
2. Power Block Diagram   
3. Power Domain and Power Sequence 

II. MB Trouble Shooting Guide 

I. Baseband Troubleshooting Guide

 ...............................................................................................................................1

 

II. MB Trouble Shooting Guide

 .......................................................................................................................................1

 

1. Outline and Component Introduction

 .........................................................................................................................4

 

2. Cannot power on ...................................................................................................................................................5

 

3. Blank screen ..........................................................................................................................................................6

 

4. LCD display failure ................................................................................................................................................7

 

5. TP does not work ...................................................................................................................................................8

 

6. Light / Distance sensor failure ...............................................................................................................................9

 

7. Gravity sensor failure...........................................................................................................................................10

 

8. Side key FPC failure ............................................................................................................................................ 11

 

9. Cannot get charged, fail to identify USB .............................................................................................................12

 

10. Rear camera function failure .............................................................................................................................13

 

11. Front camera function failure .............................................................................................................................14

 

12.Flash failure ........................................................................................................................................................15

 

13. GSM network failure ..........................................................................................................................................16

 

14. CDMA network failure ........................................................................................................................................18

 

15. LTE network failure ............................................................................................................................................20

 

16. WIFI/ BT failure ..................................................................................................................................................22

 

17. GPS failure ........................................................................................................................................................23

 

18. FM failure ...........................................................................................................................................................25

 

19. Fail to identify earphone/Handset MIC failure ...................................................................................................26

 

20. MIC no sound/small sound ................................................................................................................................27

 

21. Receiver no sound.............................................................................................................................................28

 

22. Speaker no sound .............................................................................................................................................29

 

23. Fail to identify SIM card .....................................................................................................................................29

 

24. Fail to identify T-flash card ................................................................................................................................31

 

 
 

Summary of Contents for ZENFONE T500

Page 1: ...k 8 6 Light Distance sensor failure 9 7 Gravity sensor failure 10 8 Side key FPC failure 11 9 Cannot get charged fail to identify USB 12 10 Rear camera function failure 13 11 Front camera function failure 14 12 Flash failure 15 13 GSM network failure 16 14 CDMA network failure 18 15 LTE network failure 20 16 WIFI BT failure 22 17 GPS failure 23 18 FM failure 25 19 Fail to identify earphone Handset...

Page 2: ...ASUS T500 MB Service Manual 2 I Baseband Trouble Shooting Guide 1 System Block Diagram 2 Power Block Diagram ...

Page 3: ...ASUS T500 MB Service Manual 3 3 Power Domain and Power Sequence ...

Page 4: ...ector CPU MSM8916 KB connector Battery connector PMIC Gravity sensing IC RF power amplifier LCD connector Light distance sensor connector WIFI BT GPS antenna SIM socket T Flash socket Flash MIC RF diversity antenna PA Main antenna switch 26M Crystal oscillator Flash driver IC WIFI BT GPS module RF switch Audio PA Backlight driver IC RF switch RF power amplifier SIM socket ...

Page 5: ...the start up circuit is about 20 MA check if the soldering of crystal oscillator circuit is normal 5 For those start up current abnormally above 1A check if VBAT circuit is shorted to ground investigate each locations grounding diodes and other key components 6 For those start up current abnormally around 100MA touch if there is any heating part on MB and focus on their investigation 7 X ray check...

Page 6: ...nnector s assembly is normal if not please re assemble 3 Check if L1701 L1780 s conduction is normal and compare its voltage on normal MB 4 Check if D1702 s conduction is normal or the component s soldering is reverse 5 Check if LCD_BACKLIGHT_PWM s signal is normal and adjust this signal s backlight brightness 6 Check if VBAT s power supply is normal ...

Page 7: ...bserve 2 Check if LCD and its soldering is abnormal 3 Check if LCD filter FL1702 FL1704 FL1706 FL1708 FL1710 is poorly soldered or damaged 4 X ray check if CPU s soldering is abnormal 5 Add soldering or re solder CPU or replace it Backlight driver chip L1780 LCD connector CPU MSM8912 PMIC PM8916 Backlight driver chip ...

Page 8: ...its soldering is abnormal re solder or replace it to test again 3 Measure if VREG_L6_1P8 R1506 VREG_L17_2P85 VD1509 voltage are normal 4 X ray check CPU s soldering add soldering or re solder it to test again 5 Use a multi meter to measure CTP test signal point compare its ground resistance with normal MB s 6 Replace CPU CTP connector VREG_L17_2P 85 ...

Page 9: ... 2 Measure VREG_L17_2P85 R1501 s voltage 3 Use a Oscilloscope to measure R1521 s VPH_PWR voltage and check if the control signal is normal 4 Check if the connector is abnormal re solder or replace it to test again 5 Add soldering or re solder CPU or replace it Light distance sensor connector R150 4 CPU R1501 ...

Page 10: ...rvice Manual 10 7 Gravity sensor failure Solution 1 Measure VREG_L17_2P85 s voltage 2 Add soldering or re solder or replace U1501 3 X ray check CPU and U1301 s soldering re solder or replace CPU VIO18_PMU C1502 U1501 ...

Page 11: ...ion 1 Re connect the side key FPC 2 Replace the side key FPC and test again 3 Check if VOLUME VOLUME KYPD_PWR_N s voltage signal is normal 4 X ray check CPU Volume Key PMIC U501 s soldering 5 Add soldering or re solder or replace CPU PMIC Side key Welding plate ...

Page 12: ...ify USB Solution 1 Check if KB connector is normal re connect or replace KB and test again 2 Check if KB connector J1806 is normal 3 Replace the battery and test again 4 Replace the battery connector and test again 5 Re solder PMIC PMIC KB connector Battery connector ...

Page 13: ... and again 2 Check if the rear camera s connector is damaged or poorly soldered re solder ore replace the camera connector 3 Check VREG_L10_2P8 VREG_CAM_AVDD VREG_L6_1P8 VREG_L16_CAMDOVDD s voltage 4 Check FL1701 FL1703 FL1705 FL1707 FL1709 filter is damaged or poorly soldered 5 Add soldering or re solder or replace CPU Rear camera connector Filters ...

Page 14: ...ra s connector is damaged or poorly soldered re solder or replace the connector 3 Check VREG_CAM_AVDD VREG_L6_1P8 voltage is abnormal if abnormal check if PMIC outputs abnormally or if the peripheral circuit has short open circuit 4 Check if the front camera filter FL1712 FL1713 FL1714 is damaged or poorly soldered 5 Add soldering or re solder or replace CPU Front camera connector CPU Filters ...

Page 15: ...pgrade SW and test again 2 Add 3 0V voltage at the two sides of LED welding plate check if the LED can be lighten 3 Add soldering or replace Flash 4 Check if L1702 is open circuit 5 X ray check U1702 s soldering add soldering and test again Flash Flash driver IC ...

Page 16: ...fault Solution 1 Measure MOT MOT magnitude of voltage and compare to normal MB s 2 Re solder or replace the motor and test again 3 Replace the motor connector and test again 4 Re solder or replace PMIC 13 GSM network failure PMIC KB connector ...

Page 17: ...ASUS T500 MB Service Manual 17 ...

Page 18: ...s welding normal or open circuit 3 Check if Front coupler U2001 is welding normal or is damaged 4 Check if the GSM TX channel element is welding normal or is damaged 5 Check if the U2801 RF power amplifier chip is welding normal and whether the relevant components are damaged 6 Add soldering or replace U2801 7 Add soldering or replace U1101 8 Add soldering or replace CPU 14 CDMA network failure ...

Page 19: ...ck the welding status of the antenna on the KB board and contact with the antenna on battery cover or if the body is damaged 2 Check if RF connector is welding normal or open circuit 3 Check if Front coupler FL2001 is welding normal or is damaged ...

Page 20: ...Check Filter FL2305 FL2315 FL2311 is welding normal or is damaged 6 Check if the crystal oscillator is normal 7 Add soldering or replace U2101 2102 or relevant component L2300 L2310 L2322 L2317 8 Add soldering or replace U2801 9 Add soldering or replace PMIC 15 LTE network failure ...

Page 21: ...ontact with the antenna on battery cover or if the body is damaged 2 Check if the crystal oscillator is normal 3 Check if the PA IC s voltage is normal 4 Check U2801 is welding normal or is damaged 5 Check U2001 is welding normal or is damaged 6 Check Filter FL2201 FL2202 is welding normal or is damaged ...

Page 22: ...are welding normal and if the corresponding components are damaged 8 Add soldering or replace U2801 9 Add soldering or replace PMIC CPU 16 WIFI BT failure CPU PMIC 26M crystal oscillator U2001 U2801RF transceiver IC U2500 U2601 RF switch U2201 FL2305 FL2311 FL2315 FL2201 FL2202 U2101 U2102 Diversity antenna ...

Page 23: ...irs soldering are damaged 3 Measure VREG_L5_1P8 VREG_L7_1P8 VREG_L24_1P3V s voltage 4 Check if 26M crystal oscillator normally works if the supply voltage is normal 5 Add soldering or replace 26M crystal oscillator 6 Add soldering or re solder or replace the chip U2703 U3301 U3302 and test again 7 Add soldering or re solder or replace CPU and test again 17 GPS failure ...

Page 24: ...ed 3 Measure if V VREG_L4_1P8 C3101 voltage is normal 4 Check if 26M crystal oscillator normally works add soldering or replace it and test again 5 Add soldering or re solder or replace FL3101 FL3102 U3101 and test again 6 Add soldering or re solder or replace U2801 and test again Filter FL3102 LNA U3101 WIFI BT FM IC U3302 26M crystal oscillator WIFI BT GPS Antenna shrapnel ...

Page 25: ...as soldering deviation high floating or is damaged 3 Replace there is any component and its soldering is damaged on the earphone antenna circuit 4 Measure if U3302 FM GPS WIFI IC voltage is normal 5 Add soldering or replace 19 2M crystal oscillator 6 Replace earphone socket and test again 7 Add soldering or replace U3302 and test again ...

Page 26: ...ldering deviation high floating or is damaged 3 Check if the related components of earphone are obviously poorly soldered or the earphone socket is damaged 4 Measure CDC_HS_DET voltage before and after the earphone cable is inserted voltage before 1 8V voltage after 0V 5 Replace the earphone socket and test again 6 Add soldering or re solder or replace CPU WIFI FM GPS IC U3302 earphone socket ...

Page 27: ...ASUS T500 MB Service Manual 27 20 MIC no sound small sound earphone socket ...

Page 28: ...ture which may damage the MIC 3 Add soldering or re solder or replace PMIC and test again 21 Receiver no sound Solution 1 Re assemble or replace the receiver and test again 2 Visually inspect if the components on receiver circuit and their soldering are damaged 3 Add soldering or replace PMIC and test again U1101 PMIC KB connector ...

Page 29: ...emble speaker with connector or replace the speaker 2 Visually insect the related components and their soldering 3 Add soldering or re solder or replace Audio PA VD1403 4 Add soldering or replace PMIC 23 Fail to identify SIM card KB connector PMIC U1101 Audio PA VD1403 ...

Page 30: ...ce the SIM cards and test again 2 Visually inspect if the SIM card socket has soldering deviation high floating or is damaged 3 Measure the SIM supply voltage 4 Add soldering or re solder PMIC 5 Add soldering or re solder CPU PMIC SIM socket CPU U501 SIM socket ...

Page 31: ...1 Re insert or replace the T flash card and test again 2 Visually inspect if the T flash card socket has soldering deviation high floating or is damaged 3 Measure the T flash socket s supply voltage U1602 4 Re solder or replace U1602 5 Re solder or replace CPU T flash socket ...

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