Dometic NDA1402 - Maintenance & Service; Periodic Maintenance and Checks

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The NDA/NDE1402 models use two AC heaters wired in
series. The resistance should be 34.3 Ohms +/- 10%.
Note: Never over or under size the AC heater.
3.2 Interface Module
To shut off the 120 volt AC supply to the door dispens-•
er and ice maker when the refrigerator is switched
“OFF” by means of the ON/OFF button on the upper
display panel.
The interface module is used for two reasons:
To shut off the 120 volt AC supply to the door dispens-
•
er and ice maker when the freezer door is opened (for
safety Reasons).
The function of this additional module is very simple. It
has a (5 amp) fuse for incoming 120 volt AC line volt-
age and a relay that switches the line voltage ON/OFF.
The relay is driven by a circuit that senses the voltage at
the node between the door switch and the interior lamp.
This relay is controlled by the wires in the P1 connec-
tor on the interface module. These wires are hooked on
the wires coming from the power module to the lamp and
door switch. The black wire is ground (-), the white wire is
12 volt DC (+) and the yellow wire is going to the connec-
tion point between the lamp and door switch. If the door
is opened, the yellow wire should be 12 volt DC (+) and
if the door is closed, the reading should be 0 volts DC. If
the lamp is lit or if 12 volt DC is absent, the relay will drop
out and 120 volt AC will not be supplied to the ice maker
or the door dispenser.
The tabs on the module are from left to right:
(4) Interconnected tabs that serve as intercon-
•
nection points of four neutral wires (white).
(2) Interconnected tabs that serve as intercon-•
nection points of the “auger wire” from the door
and the wire to the auger motor (yellow).
(2) Interconnected tabs that serve as intercon-•
nection points for the “cube wire” from the door
and the wire to the solenoid (red).
(2) Interconnected tabs that supply switched 120
•
volt AC to the door and to the ice maker (black).
(1) Tab for incoming 120 volt AC to the interface •
module (black).
To troubleshoot the module:
Check that the wires are correctly connected to
•
the tabs.
When the door is shut, check that 120 volt AC is •
present on the tabs (J9) and (J10).
When the door is open, check that the voltage on •
these tabs (J9) and (J10) is 0 volts AC.
If 120 volts AC is not present on (J9) and (J10) •
when door is closed, check the fuse.
If the fuse is OK, check that the interior light in the •
freezer is working, (switched on/off when press-
ing/releasing the door button).
If the interior light is OK, check if the relay is •
“clicking” when the door is opened/closed (you
will need an assistant to operate the door while
you are touching the relay with a nger to sense
if it is “clicking”.
If the relay is not clicking though the interior light •
is correctly switched ON/OFF, measure the volt-
ages on the pins in the P1 connector. The volt-
ages should be as described previous, in this
section.
If the voltages in the P1 connector are OK and •
still the relay is not clicking when opening/closing
the door, the module is faulty; the transistor that
drives the relay is probably damaged.
This is an energized circuit. Shock can occur
if not tested properly. Testing is to be done
by a qualied service technician.
Model Watts Ohms Amps
NDA 1402 420 34.3 3.5
NDE 1402 420 34.3 3.5