Samsung RF31FM Series Manual page 193

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6. Self Diagnosis & Trouble Shooting
6-8. When alarm sounds continuously without stop
(related with buzzer sound)
1) If 'ding-dong' sound continuously
Door & MICOM State
FZ
FZ MICOM(#28)
MICOM(#29)
Door
Mid-drawer
Right and Left
Micom(#27)
Close 0V(Low), 0V(Low)
Open 5V(High) 5V(High)
YES
Is the input
voltage of main #29,#28
changed at door-open and
close status?
YES
MAIN PCB & Door S/W is normal.
Recheck and replace Panel PBA
NO
Repair wire connection and
Door S/W
To do list
193