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Page 16 of 22 

2.2.4 Baseband Fault issues 

Maintenance process of the download failure Issues:   
 

 

 

 

 

 

 

 

Download Fail 

Check  to  see  if  it  is  caused  by  other 

factors such as: configuration, download 

cable, power supply, software and PC 

Exclude  the  reason  of 

download 

failure 

caused by other factors 

 

Yes 

Check  to  see  if  the  serial  ports between 

pc and cell phone is smooth 

 

Check if the system 

connector is poor 

soldered or damaged. 

NO 

NO 

Check the resistance, 

capacitance and the 

EDC devices between 

the system connector 

and the CPU. 

 

NO 

Connect the download cable then 

observe the Ammeter to see if it 

shows high current

The normal 

current generally about 30mA

 

 

Yes 

Quickly disconnect the 

connection, and gently 

touch the chip to see if it is 

hot. If not, then focus point 

using the multi-meter to 

measure the short circuit. 

 

Yes 

Check the power  manager and open the 

LDO  to  see  if  the  voltage  supply  is 

normal  and  whether  there  is  power 

supply circuit open. 

 

Little or no current 

 

Check VCORE

VDD

VADD

VTCXO

VRTC

VMEM

Measure the clock signal of 

26MHZ

32KHZ. 

 

Current normal but download fail 

 

Check CPU and NAND FLASH

SDRAM to 

see if they are OK and the LDO is normal. 

 

Содержание BLU VIVO IV

Страница 1: ...Page 1 of 22 BLU VIVO IV Service Manual...

Страница 2: ...g Path Components 8 2 2 Baseband part 10 2 2 1 Block diagram of the Baseband part 10 2 2 2 Power Management 11 2 2 3 Audio Section 12 2 2 3 1 Audio Codec Circuit 12 2 2 3 2 MIC Receiver Loop 13 2 2 3...

Страница 3: ...Audio CODEC PA YDA168B Memory SAMSUNG KMR8X0001M B608 TP IC Synaptics mXT 540S Peripheral Configuration LCD SAMSUNG 4 99 Backlight driver TI TPS65632A CAMERA 13 0MP AF rear 5 0MP FRT camera Memory ca...

Страница 4: ...22 System Block Diagram CPU MT6592V W PMIC MT6322 BATTRY CAMERA FM BT WiFi GPS LCD CTP KEYPAD MEMORY MT6166 SKY77761 11 SKY77762 11 SKY77768 11 900MHZ SKY77765 11 850MHZ YDA168 B SPK HP REC single SIM...

Страница 5: ...Page 5 of 22 1 2 Motherboard Components Distribution...

Страница 6: ...Part 2 1 1 Block Diagram of the RF Section RF Block Diagram 2 1 2 Signal flow of the RF Transmitting Pa A N T PA Ant Switch SKY77761 11 SKY77762 11 SKY77768 11 900MHZ SKY77765 11 850MHZ Alternative 9...

Страница 7: ...Check Transceiver to see if IQ signals exist Check the PA output to see if there is RF signal in the path Y Check CPU N Check RF coaxial switch or matching network Y Check the Transceiver to see if t...

Страница 8: ...Page 8 of 22 2 1 2 Signal Flow of the RF Receiving Part 2 1 3 1 Receiving Path Components Receiving path is shown in the following figure Maintenance flow chart of the receiving Issues...

Страница 9: ...Y Transceiver has received signal N Transceiver SDATA SCLK LE CXOEN are correct Y Check CPU N Whether the voltage of the transceiver is normal Whether 26MHZ is normal Y Check the corresponding power...

Страница 10: ...t 2 2 1 Block diagram of the Baseband part CPU MT6592V W PMIC MT6322 BATTERY CAMERA FM BT WiFi GPS LCD CTP KEYPAD MEMORY MT6166 SKY77761 11 SKY77762 11 SKY77768 11 900MHZ SKY77765 11 850MHZ YDA168 B S...

Страница 11: ...Page 11 of 22 2 2 2 Power Management The power management module is PMU IC MT6322 2 2 2 1 Mobile power supply system DC DC LDO...

Страница 12: ...12 of 22 2 2 3 Audio Section 2 2 3 1 Audio Codec Circuit This phone applies YDA168B which is a class D and non crack noise YAMAHA amplifier to drive speaker Block diagram of the audio system is as be...

Страница 13: ...st have a bias voltage in order to operate normally 2 0 0 1V When MIC is in good condition but loop MIC has no echo then you need to check the basic bias voltage signal of the MICBIASP and MICBIASSP t...

Страница 14: ...work as shown below 2 2 3 3 Headset Loop Headset loop includes two signals Headset speaker and MIC If the headset fitting were in good condition when the headset plug in it appears abnormal such as Th...

Страница 15: ...Page 15 of 22 FPC...

Страница 16: ...ces between the system connector and the CPU NO Connect the download cable then observe the Ammeter to see if it shows high current The normal current generally about 30mA Yes Quickly disconnect the c...

Страница 17: ...ort circuit the equivalent of a long pressing this button At this point you should analyze the following first Check the connector external exclusion and varistor to see if they are short circuit Then...

Страница 18: ...Page 18 of 22 2 2 4 2 Analysis of Display module circuit Display module use the 4 99 AMOLED LCD 2 2 4 3 FM Module FM adopts the design of MT 6632...

Страница 19: ...pixel rear camera connecting to baseband chip through connector The welding of the connector is the main reason for the camera malfunction Camera Interface Circuit Power supply circuit VCAMD_IO_PMU f...

Страница 20: ...f 22 2 2 4 5 IO Interface IO applies 5pin standard interface which realize the functions of USB charging and download 2 2 4 6 SIM Card Circuit Switch of dual SIM cards is integrated into baseband SIM...

Страница 21: ...Page 21 of 22 2 2 4 7 BT WIFI GPS Circuit BT WiFi GPS are integrated into MT6625 2 2 4 8 G sensor Circuit...

Страница 22: ...Page 22 of 22 2 2 4 9 M sensor Circuit 2 2 4 10 Gyroscope Circuit...

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