Sam4s ER-260 SERIES - 5-2 System Problems

5. Troubleshooting
5-2 SAM4S ER-260 SERIES
5-2 System Problem
End
System Problem
Reset Signal
Ok?
Y
N
1. Check the IC AME8500(U18)
2. Check the 74HC14(U20).
3. Check the RST Pattern on PCB.
Power Fail
Si
g
nal Ok?
Program run
Ok?
Y
1. Check the PSEN signal of EPROM nOE pin
2. Check the Addr/Data line Pattern whether it is short.
3. Replace the EPROM
1. Check the LM393(U27)
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 (U5).
4. Re
p
lace the SRAM.
Y
N
1. Check the Clock (36.864MHz)
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(PCF8563)