Sam4s ER-900 Series, Service Manual

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6 Troubleshooting
SAM4S ER-900/SPS-300 SERIES 6-3
6-4-4 Data memory problem (Back-up broken when power off)
„ The System-ECR has 4Mb or 16Mb SRAM and power fail sensing circuit for the data back-up. When
power off, the MCU (LPC2470) detect a point of time and perform the data back-up.
„ Check backup circuit on Main B’D
→ Check BAT43WS (D3,D4) and related component whether short or not.
→ Check battery voltage whether above 1.8V or not.
→ Check battery whether it is separated from battery socket.
→ Check SRAM (U3,U9) component whether short/open or not.
„ Check power fail circuit on Main B’D
→ Check KA393 (U12) and related component whether short or not.
6-4-5 RTC problem
„ Check backup circuit on Main B’D
→ Check the RTC clock, this frequency is 32.768KHz
→ Check battery voltage whether above 1.8V or not.
→ Check battery whether it is separated from battery socket.
6-4-6 Battery problem
„
The battery of ER-900/SPS-300 is Lithium Manganese Dioxide Rechargeable Battery (ML2032).
„ Never short circuit the battery. It is caused that back-up data is gone.
„ Do not use CR2032 battery. The CR2032 is not rechargeable battery.
„ Charging problem
→ Check relate component & circuit.
„
Battery change
→ Before changing the battery, make sure save the data on SRAM.