Sam4s ER-5100 II SERIES, Руководство по обслуживанию

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6. Troubleshooting
SAM4S ER-5100II SERIES 6-5
End
Key Board Problem
Key Input
Failure ? Y
N
1. Check the Key Scan Part 74HC138(U3,4,5)
2. Check the Key Return line.(CPU K1~k8)
3. Check the related Circuit and Pattern
4. Check & Change Key Board Assy
5. Check the KBD Connector on PBA
Specific Key
Failure?
1. Check the affected Key
2. Check the Matrix Bus & Data Bus
3. Check the Diodes(NMBD6050 * 20EA)
4. Check the Key Board Assy
N
Mode Key
Ok?
Y
Y
1. Check the Harness & Mode Key Assy
2. Check Diode (D11)
3. Check the 74HC138 & Data Bus
N
6-5 Key Board Problem