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LGE Internal Use Only
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
4.4.1 Power On Trouble
4.4.1.1 Power-On Trouble Troubleshooting
• 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
• Check Points
– Battery Voltage
– Power-On Key Detection (Pwon signal)
– Output of LDOs
• Trouble Shooting Setup
– Connect PIF-UNION to the phone.
– Set the TI-remote switch at PIF-UNION off.
• Trouble Shooting Procedure
– Check Battery Voltage
– END_KEY Dome Switch condition& Side FPCB condition
– Check the output voltages of all LDOs.
4.4. Baseband Part Troubleshooting