Samsung RT38 Service Manual page 72

REFERENCE INFORMATION
9-2. Q & A
Descriptions of symptoms
● Noise (resonance) problems
on even though the noise
generating BLDC motors for
both of the compartments are
replaced several times. What
does generate the resonance
and how can it be settled down?
● What causes the "knocking"
noises? How to solve it?
● What is the solution if the same
problem occurs even though
the counter action in the service
bulletin has been implemented
already for the "knocking"
noises?
● What causes the liquid passing
noises from the back of the
refrigerator?
● What is the solution for the
compressor noises?
● What is the solution for the
compressor noises?
Check Points
When the BLDC fan motor rotates
in low RPM, The friction with air
is quite high and it generates
"grinding" noises.
It makes 'knocking" or "branch
breaking" noises when the liner
and the shelves hit each other
due to the fluctuation of the inside
air pressure upon door open/
close. Also, these noises occur
when the liners and the shelves
hit each other as the liners
expand and contract due to the
temperature change in both of the
compartments.
Check if the selves wobble. If they do, have shelves sit firmly on their
places.
Refrigerant goes into the evaporator via the capillary tube in which the
refrigerant expands as it circulates the cooling cycle. At this time, the
refrigerant is in its liquid state and it starts evaporating as it reaches
at the inlet of the evaporator with a bigger diameter, which causes the
refrigerant noises. And, it gets worse when the refrigerant does not flow
freely.
For new refrigerators
Check if the refrigerator is leveled.
Check if there is enough clearance
at the back of the refrigerator
for the ventilation of the machine
compartment.
Required clearance around the
product.
83
Corrective Measures
If you replace the ambient
thermistor with a 2.7K resistance
(detecting 43℃), the BLDC fan
motor rotates in high RPM, which
reduces friction with air resulting
in reduction of the 'grinding"
resonance.
Check the clearance between the
selves and the liners.
① Freezer Shelves: Remove the
trim shelves already attached
and replace them with those
supplied for service.
② Fridge Shelves: Because
noisepreventing trim selves are
not attached, it needs attaching.
Check if the refrigerator wobbles
by shaking with hands.
If there is not enough clearance
or it is blocked by things such
as newspaper, there could be
resonance noises.
More than 5cm from the back,
30cm from the top and 10cm from
its sides.