28
1. Choose a no impedient environment for testing signal estate. If it gets normal, then it maybe the
envirment that infect the communication condition
2. Switch to another network to check the signal estate. If it gets normal, then the problem is caused by
the coverage of network
3. Check receiver access of the mobile phone. If it gets abnormal, please consult 8.16
8.11: Can not deliver voice signal (Receive call is able)
1. Check connection of Mic. Or else connect it again
2. Check weld for Mic and elements around. Or else weld again
3. Check conducting of D747 and D748. Displace new if the conduction is reverse
4. Measure deflection voltage of Mic. If it get abnormal, then maybe the U202 is damaged
5. Displace an eligible Mic. The former Mic maybe damaged if the new one get normal
6. Check transmitter access of the mobile phone. If it get abnormal, please consult 8.15
7. Displace an eligible U202. The former one maybe damaged if the new one gets normal, or the
interface of Mic is damaged
8.12: Drop call
1. Check inserted estate of SIM card. Insert it again if it is abnormal
2. Check the contact estate of interfaces on the mobile. Installate them if they are abnormal
3. Tune electric capability again. The reason is tune windaged or the data missin If it gets normal
4. Check transmitter and receiver access for the mobile phone. If it gets abnormal, please consult
8.15--8.16
8.13: Transmit abnormally
1): Antenna part
1. Measure the output power of antenna. Test again if it gets normal
2. Measure the output power of RF Switch. Check connection estate between antenna and main board
if the power is normal, or else, please consult RF Switch part
2): RF Switch part
1. Measure the input power of RF Switch. Please consult PA part if it is abnormal
2. Measure the voltage of VREG. It may be mulfunction at Transceiver or the capacitance is damaged if
the voltage value is not 2.8V
3. Measure the logic of TSPACT00 and TSPACT04. it may be mulfunction at DBB if the logic is
abnormal. Or else, displace new RF Switch
3): PA part
1. Measure the input power of PA. Please consult Transceiver if it is abnormal
2. Measure VBAT. It may be mulfunction at ABB or the capacitance is damaged if VBAT gets abnormal
3. Measure level of TX-EN, and Band select that under GSM mode and DCS mode. The value of TX-EN
should be high level, the one of Band select under GSM mode should be low and under DCS mode should be
high. It may be mulfunction at DBB or capacitance is damaged
4. Measure APC signal. It should be analogous square wave with occupation/unoccupied is 1/8, and t
he
changes with power’s change. It may be mulfunction at ABB if the wa
ve and is
abnormal. Or else, diplace
new PA
4): Transceiver part
1. Measure VBAT and V_IO. It may be mulfunction at ABB or capacitance is damaged if they are
abnormal
2. Measure 26MHz. It may be damaged of Transceiver if 26MHz is abnormal. Please consult Can not
turn on
3. Measure STROBE. It is mulfunction at DBB if STROBE is normal, or else, just caused by DBB maybe
8.14: Receive abnormal
1. Check the element connection among antenna to Switch. Weld missing ones if there is absent
2. Measure input signal of RF Switch. If there is none, please check elements’ absent
3. Measure VREG. It may be mulfunction at ABB if VREG is abnormal
4. Measure the logic of TSPACT00 and TSPACT04. it may be mulfunction at DBB if the logic is
abnormal
5. Measure output of RF Switch. Displace RF Switch if it is normal
6. Measure output of filter. Displace it if its attenuation too much or no signal
7. Measure signal IA, IB, QA and QB. Displace Transceiver if they are normal, or else, displace DBB
Note: RF/Logic element that used to displace mulfunction one during the maintain process must
Содержание W420
Страница 1: ...Voxtel Repair Manual Item W420 ...
Страница 23: ...23 3 LDO circuit ...
Страница 24: ...24 Cameramodule control circuit ...
