Troubleshooting - Sam4s NR-500 Series Service Manual

8 Troubleshooting

8-1. Power Problem
System Problem
Reset Signal
Ok?
Y
Power Fail
Signal Ok?
Y
CPU
Ok?
Y
Program run
Ok?
Y
SRAM Ok?
Y
RTC Ok?
Y
End
SAM4S NR-500 SERIES
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1. Check the IC AME8500AEET(U11)
N
2. Check the /RESET Signal Pattern on PCB.
1. Check the LM393(U10)
N
2. Check the Power (VPRT, VDD3.3V)
3. Check the related Circuit and Pattern on PCB
1. Check the Clock 12MHz(X1)
2. Check the Power of CPU VCC Pin (VDD3.3V)
N
3. Check the mounted state of CPU pin whether the pin is
open or short
1. Try the Download S/W
N
2. Check the Addr/Data line Pattern whether it is short.
3. Replace the CPU
1. Check the nCS, nRD, nWR signal of SRAM
N
2. Check the VBT(Battery Voltage).
3. Check the TR(Q27,Q28;2222) on Main PBA
4. Replace the SRAM.
1. Check the VBT(Battery Voltage).
N
2. Check the RTC Clock 32.768KHz (X3)
3. Replace the X-TAL
4. Replace the RTC Chip (U31)
8-1