M2 MC2125PALS Service Manual - page 52
53
Diagnostics
10-6) If the panel PCB is not working normally:
1) Where lighting of the panel PCB is disabled, or only some lamps are disabled.
2) Where the Panel PCB key isn’t selected:
- The basic check way : If you is troubleshooting in the basic check method, then
Is the connector
of upper hinge cover inserted
normally?
Start
Reinsert the connector. Troubleshoot
a poor contact.
Is the main PCB
connector(CN50) inserted
normally?
Reinsert the connector in the main
PCB.
Is the connector of
door panel PCB connector inserted
normally?
Reinsert the connector. Troubleshoot
a poor contact.
1. Check the door wire of freezer – the disconnection of wire, short between wires.
2. Check the CABI wire of freezer – the disconnection of wire, short between wires.
3. Check the panel lighting circuit section within the main PCB for short open.
1. Check the door wire of freezer – check the breaking of wire, short between wires.
2. Check the CABI wire of freezer – check the breaking of wire, short between wires.
3. Check for Short/Open of the Panel Lighting Circuit section in the main PCB.
NO
NO
YES
YES
NO
Panel PCB itself has trouble.
YES
YES
Is lighting operated
normally when the exchange of panel
PCB?
NO
NO
Recheck after the release of locking
function.
YES
Is the locking lamp lit on?
YES
Reassemble the PCB ass’y/Enforce
the cancellation of pressed keys.
NO
Aren’t a key or more buttons
pressed continuously?
YES
Reassemble the PCB ass’y/Enforce
the cancellation of pressed keys.
Operated by
separation
Isn’t the PCB system
still operated by seperating of the
mechanism?
NO
Panel PCB has trouble for itself.
YES
Is lighting
operated normally in the exchange
of panel-PCB?
YES
Replace the main PCB.
NO
Is a periodic
wave form outputted from the main
PCB IC9?
See Ref. 1: ‘View of the
connection cabinet-door
for the wire assembly’ in
the manual.
Refer to the description of
circuit operation in the
manual 10-6) Key scan
and display Circuit
selection’s, and measure
the wave pattern.(page 40)