Troubleshooting - Sam4s NR-500R Service Manual

8 Troubleshooting

8-1. Power Problem
System Problem
Reset Signal
Power Fail
Signal Ok?
Program run
SRAM Ok?
RTC Ok?
SAM4S NR-500 SERIES
N
Ok?
Y
N
Y
CPU N
Ok?
Y
N
Ok?
Y
N
Y
N
Y
End
1. Check the IC AME8500AEET(U11)
2. Check the /RESET Signal Pattern on PCB.
1. Check the LM393(U10)
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)
3. Check the mounted state of CPU pin whether the pin is
open or short
1. Try the Download S/W
2. Check the Addr/Data line Pattern whether it is short.
3. Replace the CPU
1. Check the nCS, nRD, nWR signal of SRAM
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).
2. Check the RTC Clock 32.768KHz (X3)
3. Replace the X-TAL
4. Replace the RTC Chip (U31)
8-1