Sam4s ER-5100 II SERIES, Service Manual

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6. Troubleshooting
6-2 SAM4S ER-5100II SERIES
6-2 System Problem
End
System Problem
Reset Signal
Ok?
Y
N
1. Check the IC M51953B(U21)
2. Check the 74HC14(U20).
3. Check the RST Pattern on PCB.
Power Fail
Signal Ok?
Program
Ok?
Y
1. Check the nCS, nRD signal of EPROM
2. Check the Addr/Data line Pattern whether it is short.
3. Replace the EPROM
1. Check the LM393(U24)
2. Check the Power (+24V,+5V)
3. Check the related Circuit and Pattern on PCB
N
N
SRAM Ok?
Y
Y
N
CPU
Ok?
Y
N
1. Check the nCS, nRD, nWR signal of SRAM
2. Check the VBT(Battery Volt.).
3. Check the Decoder IC 74HC138 (U16).
4. Replace the SRAM.
Y
N
1. Check the Clock (22.11MHz)
2. Check the Power of CPU VCC Pin (+5V)
3. Check the mounted state of CPU pin whether the pin is
open or short
RTC Ok?
1. Check the RTC_SCLK & SDA signal of RTC
2. Check the VBT(Battery Volt.).
3. Check the RTC Clock 32.768KHz
4. Replace the RTC(RS5C372A)