Baseband Part Troubleshooting - LG L240 Service Manual

4.4 Baseband Part Troubleshooting

4.4.1 Power On Trouble
4.4.1.1 Power-On Trouble Troubleshooting
z
Power-On Sequence
- Connecting Battery
- Power-On Key Detection
- Pwon signal goes to ABB and then ABB resets DBB by ONNOFF signal
- ONNOFF turns low(0v) to High (2.8V) and it resets DBB (Neptune)
- All LDOs (internal LDOs of ABB and external LDOs) are turned on
z
Check Points
- Battery Voltage
- Power-On Key Detection (Pwon signal)
- Output of LDOs
z
Trouble Shooting Setup
- Connect PIF-UNION to the phone.
- Set the TI-remote switch at PIF-UNION off.
z
Trouble Shooting Procedure
- Check Battery Voltage
- END_KEY Dome Switch condition
- Check the output voltages of all LDOs.
PWON
4. TROUBLE SHOOTING
END
1 2
VA501
<Fig. 1>
- 55 -