Service manual

6 Troubleshooting
6-6 SAM4S ER-900/SPS-300 SERIES
6-7 Main B’D problem (Key Board, Mode key, Drawer, MCR, Dallas-key)
6-7-1 Key Board & Mode Key
 Key Board Operation Fail
→ Check the FPC harness between Key Board and Main B’D.
→ Check the key scan part (74LVC138, U21, U23, U24) and key return part(74LVC541, U28).
→ Change the Key Board Ass’y
→ Check related circuit & component whether short or not.
 Mode key Operation Fail
→ Check the harness between Key Board and Main B’D.
→ Check the harness between Key Board and Mode Key Assy.
→ Check the key return part(74LVC541, U28).
→ Change the Mode Key Assy
→ Check related circuit & component whether short or not.
6-7-2 Drawer & Compulsory
 Drawer Operation Fail
→ Check the harness between I/F B’D and Main B’D.( Wire harness 14pin)
→ Check Drawer specification whether it is +24V drawer or not.
→ Check the cable. Refer to Chapter 2 for cable connection.
→ Check related circuit & component whether short or not.
 Compulsory Fail
→ Check the cable and compulsory connector.
→ Check the micro switch in the Drawer.
6-7-3 MCR (Magnetic Card Reader)
 Operation Fail
→ Check the harness between MCR and Main B’D, if it is connected or not.
→ Check the IC- Buffer chip (74LVC541, U35).
→ Check the CPU on Main B’D whether it works normally or dead.
→ Check related circuit & component whether short or not.
6-7-4 Dallas-Key
 Operation Fail
→ Check the harness between Dallas-Key and Main B’D, if it is connected or not.
→ Check the CPU on Main B’D whether it works normally or dead.
→ Check related circuit & component whether short or not.
→ If these are OK above but Dallas-Key does not work, Please contact our R&D.