SAMSUNG Home Appliance Service

Bottom-Mounted Freezer Model:

RB1955SW
RB1955SH
RB1955VQ
RB2155SW
RB2155SH
RB2155BB
 WARNING

IMPORTANT SAFETY NOTICE

The service guide is for service men with adequate backgrounds of
electrical, electronic, and mechanical experience. Any attempt to repair a
major appliance may result in personal injury and property damage. The
manufacturer or dealer cannot be responsible for the interpretation of this
information.

SAMSUNG ELECTRONICS AMERICA, INC.

Technical Service Guide
Copyright ⓒ2004

All rights reserved. This service guide may not be reproduced in whole or in
part in any form without written permission from the SAMSUNG ELECTRONICS
Company.

2
 Contents

1. Installation ······································ 4

2. Nomenclature ····································4

3. Product Specifications ·······························5

4. Electrical part specifications & standard ·····················5

5. Warranty information ································7

6. Interior Views and Dimensions ···························8

7. Refrigeration Cycle and Cool Air Circulation Route···············10

8. Mechanical Disassembly······························12

9. Operation Function ·································19

10. Circuit Descriptions ································26

11. Diagnostics·····································34

12. Illustrated Parts Catalog ·····························48

13. Safety instruction on services ··························56

● Appendix Ⅰ(Reference for circuit diagnostics) ·················57

● Appendix Ⅱ(Circuit diagram) ···························61

3
1. INSTALLATION

1) To protect refrigerator in movement

Use padded hand truck from side only.

2) Remove all protective tape and pad from the refrigerators.

Connect power cord. Adjust the clearance between the doors.
3) Temperature controls ard preset in the factory for
recommended settings.
The refrigerator should runs smoothly and lower the
temperature gradually.
4) Once the refrigerator temperature is sufficiently low
It is recommended to store foods in the refrigerator.
It takes a few hours to reach the preset temperatures.

2. NOMENCLATURE
2004 Models

R B 19 55 SW / XAA
Buyer code

COLOR ; SW-SNOW WHITE SH-STAINLESS PLATINUM

VQ-BISQUE GLOSSY BB-BLACK

OPTION ; 55-NO DISPENSER 77-DISPENSER

Capacity ; CU. FT

B - BOTTOM MOUNTED FREEZER (BMF)

Product ; R - REFRIGERATOR
Label Location

4
3. PRODUCT SPECIFICATIONS
Model RB1955SW/SH/VQ RB2155SW/SH/BB
Type BMF 2 Door
Temperature control Electronic control
Total 18.7 20.4
Net Capacity
3
Freezer 5.9 6.5
(ft )
Refrigerator 12.8 13.9

Net dimension
32.3 X 28.3 X 69.9 32.3 X 30.3 X 69.9
(W X D X H)
Cabinet insulation CYCLO-PENTANE
Foam
Door insulation CYCLO-PENTANE
Cabinet A.B.S
Liner
Door A.B.S
Net weight(Ib) 227 241

4. ELECTRICAL PART SPECIFICATIONS & STANDARD

ITEM STANDARD
Model RB1955SW/SH/VQ RB2155SW/SH/BB
Rated Voltage 115V
Frequency 60HZ
Model MK172C-L2U
Starting type RSCR
Compressor
Refrigerant R134a
Oil Charge Freol α-10c(Ester), 265cc
Freezer Split Fin & Tube Type
Evaporator
Refrigerator Split Fin & Tube Type
Condenser Forced & Natural Convection Type
Dryer Molecular Sieve XH-9
Capillary tube ID0.82 X L3000
Earth screw BSBN(Brass screw)
Door switch AC125V 1.4A(SSD-6D)

5
 ELECTRICAL PART SPECIFICATIONS & STANDARD
ITEM STANDARD
Type Temperature Selection ON(℉) OFF(℉)
–14℉ –12.0℉ –16.0℉
Freezer
Temperature

F-Sensor –2℉ 0℉ –4℉

8℉ 10℉ 6℉
Type Temperature Selection ON(℉) OFF(℉)
34℉ 36℉ 32℉
Refrigerator
R-Sensor 40℉ 42℉ 38℉
46℉ 48℉ 44℉
First Defrost Cycle
4hr ±10min
(Concurrent Defrost of F and R)
Defrosting Defrost Cycle(FRE) Min. 12hrs, Max. 22Hrs
Defrost Cycle(REF) Min. 6hrs, Max. 11Hrs
Pause Time 10±2min
Freezer-Sensor
Refrigerator-Sensor
Sensor FRE Evap-Sensor THERMISTOR (502AT), SPEC:5.0KΩ AT 77℉
REF Evap-Sensor
Ambient TEMP-Sensor
Electrical parts

Defrost Heater(FRE) 242W

Drain Heater(FRE) 52W
Heater
Defrost Heater(REF) 120W
Drain Heater(REF) 38W
Thermal-Fuse for preventing
overheating of Freezer Defrost-Heater
Fuse AC250V 10A 77±5˚C
Thermal-Fuse for preventing
overheating of Freezer Defrost-Heater
Capacitor RUNNING RSCR 250VAC, 12㎌
Over-Load MODEL 4TM437RHBYY-53
Protector TEMP. ON 130±5
TEMP. OFF 69±9
STARTING-
MODEL J531Q33E100M200-2
RELAY
OPERATION 10±20%
FRE. IS3210-SNP6D
MOTOR-FAN REF. IS3208-SNP6H
CIRCUIT IS3208-SCH6A
FRE(INCANDESCENT) 110V-130V/15W
LAMP
REF(INCANDESCENT) 110V-130/30W

6
5. WARRANTY INFORMATION

7
6. Interior Views and Dimensions
6-1) Shelves and Bins

• Deli drawer • Door Bin

Pull it out to disassemble. Push it up and slide it out
to disassemble.

Light

• Gallon Bin
• Glass Shelf •
Pull it out until its stop
Tilt down and slide it out. • • Vegetable Drawer
•

• Ice trays • Freezer Drawer

8
Interior Views and Dimensions
6-2) Dimensions of Refrigerator (Inches)

MODEL A B C
RB1955 24.3 28.3 57.8
RB2155 26.3 30.3 59.8

9
7. Refrigeration Cycle and Cool Air Circulation Route
7-1) Refrigerant Route in Refrigeration cycle

Compressor → Sub condenser → Cluster pipe → Hot pipe → Dryer → Capillary tube
→ R-Evaporator → F-Evaporator → Accumulator → Suction pipe → Compressor

10
Refrigeration Cycle and Cool Air Circulation Route
7-2) Cool Air Circulation

11
8. Mechanical Disassembly
Refrigerator Disassembly

Control Panel ········································ 13

Refrigerator Light ······································ 14

Freezer Light ········································ 14

Evaporator Cover in the Refrigerator ·························· 15

Evaporator Cover in the Freezer ····························· 16

Evaporator in the Freezer ································· 17

Evaporator in the Refrigerator ······························ 17

Machine Compartment ＆ Electric Box ··························18

12
 Mechanical Disassembly
Control Panel
1. Remove the screws.

2. Pull out the control panel.

3. Disconnect the wire connector.

13
 Mechanical Disassembly

Always unplug the power cord before replacing the refrigerator lamp.
There is the danger of electric shock.
Warning

Refrigerator Light Freezer Light

1. Remove the screw. 1. Remove the cover by pressing the bottom tab.

2. Remove the lamp cover by unlocking the tabs

and pulling the cover down.
2. Replace the lightbulb by turning it counter-clock
wise.

3. Replace the lightbulb by turning it counter-

clockwise.

3. Reattach the cover and check the lamp by

pressing door switch.

4. After replacing the bulb, reattach the cover

and the screw it again.
5. Plug the power cord in and check the lamp by
pressing the R-door switch.

14
 Mechanical Disassembly
Evaporator Cover in the Refrigerator
1. Remove all shelves and drawers from the 6. Disconnect the wire connector.
refrigerator.

2. Pull out the screw caps with a small flat-blade

screwdriver.
3. Remove 6 Phillps screws from the cover.
■Ductwork of the evaporator fan assembly.

4. Unlock the 2 tabs with a flat-blade screwdriver

on each side of the bottom cover.
5. Remove the evaporator cover by pulling out
from the bottom of the evaporator cover.

15
 Mechanical Disassembly
Evaporator Cover in Freezer
1. Remove all drawers from the freezer. 5. Disconnect wire connector from the top-left
corner.

2. Remove screws (2) from the support rail.

6. Remove 2 screws from the rear cover of the
freezer evaporator and unlock the tabs to
remove it.

2 screws

3. Pull down the holder of the support rail and

disconnect the wire connector to remove it.

4. Unlock the tabs around the evaporator cover

from the buttom.

②
③

16
 Mechanical Disassembly
Evaporator in Refrigerator Evaporator in Freezer
Evaporator is located in the bottom of refrigerator. Evaporator is located in the bottom of freezer to
1. Take off the ductwork in refrigerator. produce cold air driven across the evaporator coils.
2. Disconnect the wire connector.(Heater and 1. Take off the ductwork in Freezer.
Thermistor) 2. Disconnect the wire connector (Heater,
3. Desolder the capillary tube and the suction line Bimental, and Thermistor).
from the evaporator. 3. Desolder the inlet and outlet tubes.
4. Remove the evaporator. 4. Remove the evaporator.
5. With a file, score the capillary tube just 5. Take the same steps to seal the system as
upstream of the soldered point. Break off the mentioned earlier.
soldered section to help prevent solder from
plugging the tube during soldering.
6. Place a new evaporator and braze the suction
and capillary tube to evaporator using silver
solder. Accumulator
7. Install a replacement dryer.
8. Evacuate and recharge the system using
reasonable procedures.

Thermal
Fuse

Thermal Thermistor
Fuse

Thermistor

17
 Mechanical Disassembly
Machine Compartment ＆ Electric Box 3. Mechine compartment assembly
Make sure the power cord is
unplugged before replacing any
Warning electric components.
1. Unplug the power cord.

4. Disassemble the electric box cover after

removing the screws with a Phillips screwdriver.

2. Remove the screws of the compartment cover.

Slide it up and take out from the refrigerator.

5. Electric box assembly

18
9. Operation Function
9-1) Digital Panel ···································20

9-2) Temperature Control Function ·························20

9-3) Power Freeze and Power cool Functions ··················· 20

9-4) Sound Function ································· 21

9-5) Defrost Function ································· 21

9-6) Forced Operation Function ··························· 22

9-7) Power failure compensating Function ····················· 23
9-8) Exhibition Function ······························· 23
9-9) Self - Diagnostics Function ··························· 23
9-10) Component Load Operation Function. ···················· 24
9-11) C-Fan Motor Delay function ·························· 25

19
Operation Function
9-1) Digital Panel

9-2) Temperature Control Function

When the system power is initally engaged, the default set temperature are -2℉ for the freezer and 38℉ for
the set refrigerator, respectively. The numbers shown on the digital display panel stand for the actual
compartments temperatures. When the compartment temperatures go down, so do the numbers on the
display panel, and finally they reach the set temperatures. Once the system is stabilized, the display
temperatures are the set temperature.
1) Freezer Temperature Control.
To select a set temperature, press the Freezer Temp. button. The display shows the set temperature from -
14℉ to 8 ℉ in sequence.
2) Refrigerator Temperature Control.
To select a set temperature, press the Refrigerator Temp. button. The display shown the set temperature
from 34℉ to 46℉ in sequence.
3) Child Lock Button
When these two buttons are pressed at the same time for 3 sec., the Power Freeze, Power Cool, Freeze
Temp, Refrigerator Temp, are locked and can not be modified. If you press the two buttons at the same
time again for 3 sec., the child lock function is cancelled.

note) Because of the temperature sensor sensivity, the refrigerator can be under and/or over cooled when
the air flow is blocked by stored foods. (Temperature range of the sensor : 15℉∼80℉)
In the event of a power failure, if the freezer temperature is maintained lower than 41℉, the last

9-3) Power Freeze Function and Power Cool Functions.

● Select the Power Freeze or Power Cool buttons separately.

● These buttons are toggled ON and OFF and the indicators as well.
● Although you select Power Freeze or Power Cool, the set temperatures in the freezer and refrigerator are not changed.
● The set temperatures for the compartments can be changed while these functions are in use.

1) Power Freeze function

1-1) When you press the Power Freeze button, the LED indicator lights right away, but there is 10 seconds lag time to an
actual operation. When this button is pressed again, the Power Freeze function stops and the indicator is off immediately .
1-2) If you select Power Freeze, both the compressor and the freezer fan run for 2 ½ hours continuously.
1-3) During Power Freeze, the freezer retains the current settings.
1-4) When Power Freeze expires, the indicator goes off and the freezer set temperature will be restored.

2) Power Cool function

2-1) Power Cool operation and the indicator work exactly same as the Power Freeze function.
2-2) When Power Cool is selected, COMP and R-FAN operate continuosly until the refrigerator reaches 25℉. This function will
be terminated after 2 ½ hr running.
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Operation Function

3) When you select Power Freeze and Power Cool together

Each function works at the same time. The COMP and F-FAN run continuously and the R-FAN runs until 25℉
in the refrigerator.

4) Initial Power-On
4-1) When the freezer and the refrigerator temperatures are higher than 14℉ and 50℉, respectively, if Power Freeze is
selected, then the R-FAN will be off. If Power Cool is selected, then the F-FAN will be off.
4-2) When both functions are selected, there is no benefit of fast cooling for each compartment.

9-4) Sound Function

1) Sound function
1-1) To make sure a command input, whenever a button is pressed, a “ding-dong” sounds.
1-2) When two or more buttons are pressed simultaneously or if a wrong button is pressed, there is no
sound.

2) Door Open Alarm

2-1) When the doors remain open for 2 minutes, there are 10 times beeps.
2-2) If the doors continue to remain open more than 2 minutes, the additional 10 beeps interval will change to
1 minute.
2-3) The beeps will cease immediately when the doors are closed.

9-5) Defrost Function

1) A defrost is determined based on the accumulated compressor on-time.

2) When the power is engaged for the first time, the defrost cycle for the freezer and the refrigerator will begin
after 4 hours of the accumulated compressor on-time.

3) A defrost interval depends on the ambient temperature, the number of door openings, and the door open
time.

4) The defrost cycle is composed of a pre-cool process (F-Fan and COMP) for 30 minutes, a heating
process, and a resting for 8-12 minutes to drain.

5) A minimum interval is 6 hours and a maximum is 11 hours for the refrigerator, and 12 hours and 22 hours
for the freezer, respectively.

6) When the system runs only for the refrigerator (R-Fan and COMP) and if the refrigerator can not reach the
set.

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Operation Function
9-6) Forced Operation function (Power cool key + Refrigerator. Temp 8sec.)

● This function enables a pull-down mode, a defrost mode for the refrigerator only, a defrost
mode rigerator at the same time, and a cancellation of this function.
● Press Power Cool and Refrigerator Temp. buttons for 8 seconds simultameously to get in the
ready mode for a forced operation.
● The display panel will return to normal after 15 seconds in the ready mode.
● At the ready mode, press any button once to start a pull-down operation, twice for a defrost
cycle for the refrigerator, three times for a defrost cycle for the freezer and the refrigerator, and
finally four times for cancellation of this function.
● Another way to cancel this function is to simply plug out and in the power cord.

1) Pull-down Operation
1-1) At the ready mode, press any button once then the buzzer will beep (ON for 1/2 second and
OFF for 1/2 second) until this mode is cancelled.
1-2) At this pull-down mode, the compressor will start immediately (No 5 minute delay) and if the
system is in the defrost cycle, it will be cancelled right away.

note) If this pull-down mode begins right after the compressor was off, the compressor may not
start to run due to an overload condition.

1-3) At this mode, the compressor and freezer fan will operate continuously for 24 hours and the
refrigerator fan will be on and off according to the set temperature(34℉)
1-4) After 24 hour operation, the system will be cycled at -14℉ for the freezer and 34℉ for the
refrigerator.
1-5) In order to cancel this mode at any time, select the next mode on the ready mode or power
off the system.

2) Defrost operation
2-1) At the pull-down mode, press any button again on the ready mode to begin the defrost cycle
for the refrigerator.
2-2) The beep sound continues for 3 second at the beginning, then ON for 3/4 seconds and OFF
for 1/4 second until this mode cease.
2-3) After this operation, the system will come back to normal operation.
2-4) At this mode, press any button again on the ready mode to operate the defrost cycles for
both compartments.
2-5) The beep sound continues for 3 seconds at that time, then ON for 1/4 second and OFF for
3/4 seconds until the defrost operation cease.

3) Cancellation
3-1) At the R,F-Defrost mode, press ant button again on the ready mode to return to a normal
operation.
3-2) Simply unplug the power cord, then plug it again to return to a normal operation.

22
 Operation Function
9-7) Power failure compensating function

1) When the freezer temperature is lower than 50℉, all functions on the display panel will be restored.
2) When the freezer temperature is higher than 50℉, all functions will be initialized.
(2℉ for the freezer, 38℉ for the refrigerator, and Cubed for the Ice Type)

9-8) Exhibition Function

l This function is for a display purpose on the floor of show room or store.

1) Mode ON/OFF
1-1) For the exhibition mode, press Power Freeze and Freezer Temp. buttons simultaneously for 5
seconds until a “ding-dong” sounds.
1-2) Press the same time buttons again for 5 seconds to cancel this mode put with a “ding-dong”
sound.

2) Operation
2-1) Most of the system function except the compressor operation are working properly.
2-2) There is no defrost cycle in this mode.

9-9) Self-Diagnostics function

1) Self-Diagnostics in the initial Power ON
1-1)The control board performs a self diagnostics test within 1 second and check out the temperature
sensors abilities.
1-2) If a sensor failure occurs, a corresponding LED segment will blink.
1-3) When a LED segment blinks, only the cancellation function (Press Power Freeze and Power Cool
buttons simultaneously for 8 seconds) is acceptable.
1-4) After a replacement of bad sensor or a cancellation of this function, this self diagnostics will end.

2) Self-Diagnostics in the normal operation

2-1) To select this function, press Power Freeze and Power Cool buttons simultaneously for 5 seconds
with an audible tone.
2-2) In the self diagnostic mode, only corresponding LED segments will be illuminated (see the check
list on)
2-3) After a 30 second illumination of error signal, the system will return to the normal operation.

23
Operation Function
Table 1. Display table of self diagnosis.

No Item LED Display Details Remarks

1 R-sensor REFRIGERATOR • Connector contact failure •Suspected to be below -58℉

• Short-circuit •Suspected to be over 150℉

R-defroster REFRIGERATOR
2 • Connector contact failure •Suspected to be below -58℉
sensor
• Short-circuit •Suspected to be over 150℉

3 Outer sensor FREEZER • Connector contact failure •Suspected to be below -58℉

• Short-circuit •Suspected to be over 150℉

FREEZER • Connector contact failure •Suspected to be below -58℉

4 F-sensor
• Short-circuit •Suspected to be over 150℉

F-defroster FREEZER • Connector contact failure

5 •Suspected to be below -58℉
sensor • Short-circuit
•Suspected to be over 150℉

9-10) Component Load Operation Function

1) In the normal operation, press Power Freeze and Power Cool buttons simultaneously for 3 second,
then the display panel will blink for 2 seconds.
2) Press Refrigerator Temp. button to get into this check mode with an audible tone.
3) Each illuminating LED segment stands for the component which has an ouput signal from the control
board.
4) This mode will terminate automatically after 30 seconds.

24
 Operation Function
FREEZER:10digit
FREEZER: 1digit
REFRIGERATOR:10digit
REFRIGERATOR: 1digit
Table 2. Display table of the presently operating parts.

No Content Display LED Operation Remark

1 R-fan a : REFRIGERATOR 1 digit Include R-fan activation
2 R-defrost heater c : REFRIGERATOR 1 digit Defrost heater activation
3 Initial start mode d : REFRIGERATOR 1 digit Initial power is activated ON
4 Over load mode e : REFRIGERATOR 1 digit Outer temperature is over 95℉
Ref. 6.button scan
5 Low temp.mode f : REFRIGERATOR 1 digit Outer temperature is below 68℉
and display circuitry
6 Exhibition mode g : REFRIGERATOR 1 digit Exhibition mode is operated together
7 Comp a : FREEZER 1 digit Led ON when COMP activation is included
8 F-fan b : FREEZER 1 digit Led ON F-fan activation is included
9 F-defrost heater d : FREEZER 1 digit Led ON when F-heater activation is included
10 F-Lamp a : FREEZER 10 digit Led ON when F-lamp activation is included
11 R-Lamp b : FREEZER 10 digit Led ON when R-lamp activation is included

※ 3, 4, and 5 only explains the system operation states according to the ambient condition.

9-11) C-Fan Motor Delay Function of the Machine Compartment

l According to the ambient temperature, the condenser fan located in the machine compartment is
operated with different modes.

Ranges of ambient temp. Operation

Above 66℉ C-FAN is ON as soon as the compressor is on.
C-FAN
61℉ ~ 65℉ C-FAN is ON with 5 minutes delay from the compressor on.
Delay function
Below 60℉ C-FAN is OFF regardless of the compressor operation.

25
10. Circuit Descriptions

10-1) Source Power Circuit ································ 27

10-2) Oscillator Circuit ··································· 27
10-3) Reset Circuit ····································· 28
10-4) Door S/W Sensing Circuit ······························ 28
10-5) Temperature Sensing Circuit ···························· 29
10-6) Key Scan and Display Circuit ···························· 30
10-7) Load Drive Circuit ·································· 31
10-8) Option Circuit ····································· 32

26
Circuit Descriptions
10-1) Source Power Circuit

Voltage Circuit used

(DC 12V) Relay Operation & LED Display

Vcc (DC 5V) Power around MICOM & Sensor Detector

1) The input AC voltage drops to AC 8 volts on the transformer secondary side between ①~③ at CN
10. The rectified voltage passed through D101 ~ 104 becomes DC 5V through voltage regulator
MC7805(REG1).
This (DC5V) is supplied to the control board and sensor’s circuits.

2) The input AC Voltage drops to AC 15 volts on the transformer secondary side between ⑤~⑦ at
CN 10. The rectified voltage passed through D105 ~ D108 becomes DC 12V through voltage
regulator MC7812CT (REG2).
This (DC12V) is supplied to the relay operation and LED display.

10-2) Oscillator circuit

It is designed for clock generation and time

calculation for synchronizing transmission and
reception on the logic elements inside the MICOM.
If the X-TAL specification changes, MICOM may
make an error.
Port Oscillating Frequency (The standard components should be used.)

Xin(#19) 4.00MHz

Xout(#20) 4.00MHz

±0.5% Error

27
Circuit Descriptions
10-3)Reset Circuit

When the power is supplied to MICOM, the reset

circuit initializes RAM and other sectors of MICOM.
A reset voltage maintains “low” for hundreds of µsec
comparing to MICOM Vcc voltage when the power is
in. It also maintains “high”(5V) during normal
operation. But, when Vcc drops to 3.4V-3.7V, a reset
Port Voltage port becomes “low”.
Vcc DC 5V

Reset DC 5V

10-4) Door S/W Sensing Circuit

DOOR Door Conditions Door S/W Contact MICOM Micom Input Voltage
PIN NO
CLOSE OPEN “HIGH”
F # 39
OPEN CLOSE “LOW”

CLOSE OPEN “HIGH”

R # 40
OPEN CLOSE “LOW”

1) If a door is open, the door S/W contact is closed. Then MICOM receives “low” signal and
detects door open, A relay control circuit receives “HIGH” signal and turn Lamp on.
2) If a door is closed, the door S/W contact is open. Then MICOM receives “high” signal and
detects door close, A relay control circuit receives “LOW” signal and turn Lamp off.

28
Circuit Descriptions
10-5) Temperature Sensing Circuit

( Air Sensor)
When Sensor is open When sensor is cut off

MICOM input “HIGH” MICOM input “LOW”

1) The sensor uses the characteristics of thermistor. If temperature goes higher, resistance goes
lower. On the contrary, if temperature goes lower, resistance goes higher.
2) A MICOM input voltage is calculated by sensor as follows.
RTH (VCC : 5V, RTH : Sensor reisitance)
VF = X Vcc
RTH + R301
3) For the resistance data corresponding to a temperature and a MICOM input voltage, please
refer the conversion table on the back.

29
Circuit Descriptions
10-6) Key Scan and Display Circuit

If the IC04 decorder(KID65783AD) receives signals from MLCOM pins(34-6), an output signal per
2 miliseconds comes out from Grid#1-#7. A step DC12 volt peak will be generated periodically as
follows:

30
Circuit Descriptions
10-7) Load Drive Circuit

1) Most of relays can control the compressor, heaters and several option functions.
2) For the compressor, #12 pin of MICOM signals HIGH(5V). This signal enters to #2 of IC03 and #15
of output terminal will be on and grounded. When the rely RY71 is switched to NO terminal a 115V
power is supplied to the compressor. If MICOM outputs LOW(0V), the compressor will stop.
3) If the RY71 is connected to NC, RY72 and 73 for defrost heaters will be on and corresponding heater.

RELAY
Load Remark
COMP Defrost Heater
on off Comp Operation Defrost-Heater Power Off

on on Comp off, Defrost-Heater Off

off on Defrost-Heater On Comp Power Off

off off Comp Off, Defrost-Heater Off

Will be activated according to the signal from MICOM. Like the above block diagram, operation of F,
R defrost heater is determined by the operation of the relay for COMP.

31
Circuit Descriptions
10-8) Option Circuit

Temperature and function values can be abjustable by using main PCB switching diode.
• Note : the values have been preset in factory. If is recommended not to change the value arbitrarily.
When the option function is modified, a power should be turned off and on, again.

1) Freezer Temperature Shift (Unit ˚F) 2) Refrigerator Temperature Shift (Unit ˚F)

SHIFT D601 D602 D603 SHIFT D604 D605 D606

Reference - - - Reference - - -

-1.0 - - • -1.0 - - •
-2.0 - • - -2.0 - • -

-4.0 - • • -4.0 - • •
-6.0 • - - -6.0 • - -

+2.0 • - • +2.0 • - •
+4.0 • • - +4.0 • • -

+6.0 • • • +6.0 • • •

32
Circuit Descriptions

33
11. Diagnostics
11-1) If power is not ON

Caution!
To check the main PCB,
At the power of main PCB, the 115V power and a high- please apply descriptions of
voltage over DC 170V occur. Special care should be operation and references in
the manual.
advised on repair and measurement.

34
 Diagnostics
11-2) If there is a trouble with self-diagnosis
1) If the ambient sensor has trouble.

2) If the temperature sensor of the refrigerator has trouble.

35
 Diagnostics
3) If the defrost sensor of the refrigerator has trouble.

4) If the temperature sensor of the freezer has trouble.

36
 Diagnostics
5) If the defrost sensor of the freezer has trouble.

37
Diagnostics
11-3) If the compressor is not working properly

Pre-check
1. A compressor does not operate within 5 minutes after compressor is OFF.
2. A compressor does not run during defrost period
3. A compressor does not run because a low temperature is detected if freezer and the
refrigerator sensor are not connected.

38
Diagnostics
11-4) If cooling fan doesn’t work

Pre-check
Select a pull-down mode from the forced operation function
1. When COMP is OFF both freezer and the refrigerator cooling fans and COMP cooling fan
remain OFF.
2 . When COMP is ON, the refrigerator fan is not always ON and when the refrigerator
temperature reached a set temperature, the fan goes OFF.
3. When both the freezer and the refrigerator doors are closed, each fan has a delay time
(5sec ~ 1 min) and then degins to run. (COMP ON condition)

4-1) When freezer fan (F-fan) do not operate

39
Diagnostics
11-5) If the refrigerator fan doesn’t work

40
Diagnostics
11-6) If the compressor cooling fan motor doesn’t work

41
Diagnostics
11-7) No defrosting
Pre-check

1. Although both F R-defrost sensors have short-circuit, a normal operation continues

without a defrost cycle (Refer to self - diagnostics function)
2. When the temperature fuse is open, there is no heating and a defrost occurs naturally by
the compartment temperature increase and eventually, it will cause a blinking of
temperature.
3. When both F R-defrost sensors are open, heating does not end. The compressor remains
off and a temperature fuse will be open. (Refer to self-diagnostics function.)

42
Diagnostics

43
Diagnostics
11-8) Alarm continuously

Pre-check
1. Alarm begins after 2 minutes when the door is open and runs in every 2 minutes.
2. If the door is not closed properly, MICOM will indicate that the door is open, and alarm
continues. If the alam goes for 10 minutes, the light in the compartment will be off and not
be on in the situation that the door opens.

1) If melody sounds continuously

44
Diagnostics
2) If beep sounds continuously

3) When the digital panel PCB does not light

45
 Diagnostics

4) When a button of the digital panel is not selected

46
 Diagnostics
Pre-check
1. Is the power cord connected to a wall outlet correctly?
2. Be careful of high-voltage, high-frequency discharge from the electronic ballast.

5) If the lamp of refrigerator fails to light

47
12 . Illustrated Parts Catalog.
12-1) Freezer

48
 Illustrated Parts Catalog.
■ Parts List of Freezer
NO CODE-NO PART NAME OPTION
RB1955 RB2155
SPEC
1 DA67-40203N TRAY-ICE,ASSY l l
2 DA67-40182A TRAY ICE l l
3 DA97-00682A TRAY-FRE UPP,ASSY l
DA97-00682B TRAY-FRE UPP,ASSY l
4 DA63-01260A COVER-TRAY FREE, UPP l l
5 DA97-00683A TRAY-FRE MID,ASSY l
DA97-00683B TRAY-FRE MID,ASSY l
6 DA63-01272A COVER-TRAY FREE, MID l l
7 DA97-00684A TRAY-FRE LOW,ASSY l
DA97-00684B TRAY-FRE LOW,ASSY l
8 DA63-01259A COVER-TRAY FREE, LOW l l
9 DA66-10104A ROLLER FRE l l
10 DA71-20145A FIXER ROLLER l l
11 DA63-00904B TRAY ICE CUBE l
DA63-00922B TRAY ICE CUBE l
12 DA97-00181A COVER EVAP FR(FRE),ASSY l l
13 DA97-00192F EVAP-FRE ASSY l l 115V/242W
14 DA47-00095E ASS’Y-FUSE THERMO(77˚C) l l EVAP FRE.250V
15 DA32-00006C SENSOR ASSY l EVAP FRE
16 DA97-00122E ASSY SUPT-FREE l 110~130V
DA97-00122F ASSY SUPT-FREE l 110~130V
17 DA61-70114B SUPPORT-FREE,L l l
18 DA61-70115C SUPPORT-FREE,R l l
19 DA63-40006A GROMMET RAIL l l ASSY SUPT-FREE
20 DA63-00924A COVER-LAMP,FRE l
DA63-00923A COVER-LAMP,FRE l
21 DA47-00069C LAMP HOLDER l l
22 DA32-10105S SENSOR ASSY l l ASSY SUPT FREE
23 4713-001035 LAMP-INCANDESCENT l l 110~130V/15W
24 DA97-00390D COVER-EVAP RE(FRE),ASSY l l 115V
25 DA63-00903A COVER-EVAP REAR l l
26 DA61-00081B CASE-MOTOR l l
27 DA31-00019A FAN-PROPELLER l l
28 DA31-00002V MOTOR-FAN l l 115V,60HZ
29 DA63-00771A GROMMET-FAN MOTOR l l
30 DA97-00195D DRAIN PLATE FRE ASSY l l 115V/52W

49
Illustrated Parts Catalog.
12-2) Refrigerator

50
 Illustrated Parts Catalog.
■ Parts List of Refrigerator
NO CODE-NO PART NAME OPTION
RB1955 RB2155
SPEC
1 DA97-00681A CASE-VEG,ASSY l
DA97-00681B CASE-VEG,ASSY l
2 DA63-01270A COVER-VEG l l
3 DA64-00656A KNOB-HUMIDITY l l
4 DA66-10104A ROLLER FRE l l
5 DA71-20145A FIXER ROLLER l l
6 DA61-00761A RAIL-VEG, MID l
DA61-00760A RAIL-VEG, MID l
7 DA97-00663A COVER-VEG ASSY l
DA97-00663B COVER-VEG ASSY l
8 DA64-00449A TRIM-COVER,VEG l
DA64-00448A TRIM-COVER,VEG l
9 DA67-00505L SHELF GLASS l COVER VEG
DA67-00505M SHELF GLASS l COVER VEG
10 DA97-00664A SHELF REF-MID,ASSY l
DA97-00664B SHELF REF-MID,ASSY l
11 DA97-00664C SHELF REF-UPP,ASSY l
DA97-00664D SHELF REF-UPP,ASSY l
12 DA64-00450A TRIM-SHELF REF l SHELF(MID/UPP)
DA64-00451A TRIM-SHELF REF l SHELF(MID/UPP)
13 DA67-00505J SHELF GLASS l SHELF(MID/UPP)
DA67-00505K SHELF GLASS l SHELF(MID/UPP)
14 DA61-00368A RAIL-CHILLED,L l SHELF-UPP
DA61-00367A RAIL-CHILLED,L l SHELF-UPP
15 DA61-00370A RAIL-CHILLED,R l SHELF-UPP
DA61-00369A RAIL-CHILLED,R l SHELF-UPP
16 DA63-00945A TRAY CHIL ROOM-ASSY l
DA97-00296D TRAY CHIL ROOM-ASSY l
17 DA63-00925A COVER-LAMP REF l l
18 DA67-40250E TRAY-UTILTY l l
19 4713-001145 LAMP-INCANDESCENT l l 130V, 30W
20 DA96-00017C EVAP-REF ASSY l l 115V, 120W
21 DA32-00006C SENSOR ASSY l l EVAP-REF
22 DA47-00095D ASSY-FUSE THERMO(R)(77˚C) l l EVAP-REF, 250V
23 DA97-00459F COVER-EVAP REF ASSY l l 115~127V, 60Hz
24 DA63-00933A COVER-EVAP FR REF l l
25 DA63-00932A COVER-EVAP RE REF l l
26 DA63-00183B COVER-MOTOR l l
27 DA31-00016A FAN-CIRCUIT l l
28 DA63-00934B COVER-SENSOR REF l l
29 DA64-00452C TRIM-COVER SENSOR l l
30 DA60-00033A SPACER-DUCT l l 220V~240/50Hz
31 DA31-00003N MOTOR-FAN l l 115V
32 DA63-00771A GROMMET-MOTOR l l
33 DA32-10105T SENSOR ASSY l l COVER EVAP
34 DA62-00106A SEAL-COVER EVAP RE l l
35 DA62-00109A SEAL AIR SIDE l l
36 DA97-00441B PLATE-DRAIN REF ASSY l l 115V/38W
51
Illustrated Parts Catalog.
12-3) Disassembly of Door

52
 Illustrated Parts Catalog.
■ Parts List of Freezer Door
CODE-NO PART NAME OPTION
RB1955SW/2155SW RB1955VQ RB2155BB RB1955SH/2155SH
SPEC
1 DA91-01768C ASSY FOAM-DOOR REF l SNOW WHITE
DA91-01768D ASSY FOAM-DOOR REF l BISQUE
DA91-01768E ASSY FOAM-DOOR REF l BLACK
DA91-01768F ASSY FOAM-DOOR REF l STAINLESS PLATINUM
2 DA71-40135A STOPPER DOOR, MID l l l l
3 DA71-40183C STOPPER DOOR, LOW l SNOW WHITE
DA71-40183P STOPPER DOOR, LOW l BISQUE
DA71-40183Q STOPPER DOOR, LOW l BLACK
DA71-40183R STOPPER DOOR, LOW l STAINLESS PLATINUM
4 DA91-01767C ASSY FOAM-DOOR FRE l SNOW WHITE
DA91-01767D ASSY FOAM-DOOR FRE l BISQUE
DA91-01767E ASSY FOAM-DOOR FRE l BLACK
DA91-01767F ASSY FOAM-DOOR FRE l STAINLESS PLATINUM
5 DA63-01052A GASKET-DOOR SUB FRE l l l l
6 DA63-00926B GUARD-REF UPP, L l l l l
7 DA63-00927B GUARD-REF UPP, R l l l l
8 DA63-01262A GUARD-REF MID l l l l
9 DA63-01263A GUARD-REF LOW l l l l
10 DA61-00365B GUIDE-BOTTLE l l l l
11 DA61-00378A HINGE-UPP ASSY l l l l
12 DA61-00361A HINGE-UPP l l l l
13 DA63-50145A SHIM-HINGE UPP l l l l
14 DA67-00546A CAP HINGE UPP l SNOW WHITE
DA67-00546G CAP HINGE UPP l BISQUE
DA67-00546H CAP HINGE UPP l BLACK
DA67-00546J CAP HINGE UPP l STAINLESS PLATINUM
15 DA61-10153E HINGE-MID, ASSY l l l l
16 DA61-10142C HINGE-MID l l l l
17 DA63-50139C SHIM-HINGE MID l l l l
18 DA97-00352X ASSY COVER CONTROL PANEL l SNOW WHITE
DA97-00352Y ASSY COVER CONTROL PANEL l BISQUE
DA97-00352Z ASSY COVER CONTROL PANEL l BLACK
DA97-00352W ASSY COVER CONTROL PANEL l STAINLESS PLATINUM
19 DA63-00909F COVER CONTROL PANEL l SNOW WHITE
DA63-00909J COVER CONTROL PANEL l BISQUE
DA63-00909K COVER CONTROL PANEL l BLACK
DA63-00909L COVER CONTROL PANEL l STAINLESS PLATINUM
20 DA64-00444A BUTTON-PCB, L l l l l SILVER
21 DA64-00445A BUTTON-PCB, R l l l l SIVLER
22 DA63-00915A GASKET BUTTON PCB, L l l l l
23 DA63-00916A GASKET BUTTON PCB, R l l l l
24 DA41-00225A PANEL PCB l l l l

53
Illustrated Parts Catalog.
12-4) Cabinet

54
 Illustrated Parts Catalog.
■ Parts List of Cabinet
CODE-NO PART NAME OPTION
RB1955SW/2155SW RB1955VQ RB2155BB RB1955SH/2155SH
SPEC
1 DA61-10145D HINGE-LOW l l l l
2 DA64-20138B TRIM-PLATE, ABSORBER l l l l
3 DA63-10262F COVER-LEG l SNOW WHITE
DA63-10262R COVER-LEG l BISQUE
DA63-10262S COVER-LEG l BLACK
DA63-10262T COVER-LEG l STAINLESS PLATINUM
4 DA34-00122D SWITCH DOOR l l l l
5 DA61-00758A CASE-PCB PANEL l l l l
6 DA67-30218R CAP-SCREW l SNOW WHITE
DA67-00322M CAP-SCREW l BISQUE
DA67-00322N CAP-SCREW l BLACK
DA67-00322G CAP-SCREW l STAINLESS PLATINUM
7 DA26-30111J TRANS POWER l l l l
8 2501-001045 C-OIL l l l l 115V
9 DA63-01271A COVER-PCB PANEL l l l l 250V, 12uF
10 DA41-00128D PBA-MAIN l l l l
11 DA63-00951A GROMMET-DRAIN HOSE, A l l l l 115V
12 DA63-00951B GROMMET-DRAIN HOSE, B l l l l REF(￠10)
13 DA62-20001Q TUBE-PVC l l l l FRE
14 DA97-00408B COVER-COMP ASSY l l l l
15 DA31-00010B FAN-ASY l l l l
16 DA31-10110G MOTOR-CIRCUIT l l l l
17 DA73-10109A PIPE-CONNECT l l l l 115V/60Hz
18 DA97-00180N TRAY-DRAIN WATER ASSY l l l l 115V
19 DA63-40171B GROMMET-SUCT PIPE, A l l l l PIPE-SUB COMA
20 DA63-40171D GROMMET-SUCT PIPE, B l l l l PIPE-SUCT
21 DA73-10314L PIPE-SUB COND ASSY l l l l
22 DA65-20101B CLAMP-COMP l l l l R134a
23 MK172C-L2U COMPRESSOR l l l l
24 DA73-30102B DRYER-ASSY l l l l 4TM437RHBYY-53
25 DA34-10003D PROTECTOR O/L l l l l J531Q33E100M200-2
26 DA35-10013N RELAY-PTC l l l l
27 DA63-10352A COVER RELAY l l l l
28 DA71-60141D CHASSIS-COMP ASSY l l l l
29 DA61-40101C CASTER-REAR l l l l
30 DA60-90124A RIVET-CASTER l l l l
31 DA61-00178A LEG-ASSY l l l l
32 DA63-40004A GROMMET COMP l l l l
33 DA62-00217A SEAL-SUB COND l l l l

55
13. Safety Instructions on Service

●Unplug the refrigerator before making any repair or any replacement.

Avoid the electric shock.

●Use the rated components on the replacement.

Check the correct model number, rated voltage, rated current, operating temperature and so
on.

●On repair, be sure that the wires such as harness are bundled tightly and are not exposed by
water.
Bundle wires tightly in order not to be detached by the external force.

●On repair, remove completely dust, particles or other things on housing parts, harness parts,
and connectors.
Cleaning may prevent fire by tracking or short.

●Check if there is any trace indicating the infitration of water on electrical parts.
If there is a trace, change the related components or do the necessary action
such as taping using the insulating tape.

●After repair, check the assembled state of parts.

It must be the same assembled state as before.

●Check the surrounding conditions of the installed refrigerator.

When the refrigerator is located at humid or wet place, or the installed state is
unstable, change the location.

●If needed, do the ground.

Especially, if there is a possibility of the electric leakage, this appliance must be
properly grounded.

●Do not allow consumers to use one outlet for several plugs.

●Check if the power cord is placed under other appliance and so was damaged, worm-out and
squeezed.
Repair defective power plug or outlet immediately.
Make sure that the power cord is not placed under other appliance or squeezed.

●Do not allow consumers to keep bottles or the likes in the Freezer or to keep foods in unstable
position.

●Do not allow consumers to repair the appliance by themselves.

●Do not allow consumers to keep other chemicals except food.

Medicines and other materials for research ; This appliance will not maintain the precisely
constant temperature for them.
Volatile material(Alcohol, Benzene, Ether, LP gas etc.) : possibility of explosion

56
Appendix Ⅰ(Reference for circuit diagnostics)
Ref.1) Wire connector on the cabinet door.

Ref. 2) How to check relay failure

* Disconnect the wire connector from the main

PCB CN70, 71 and measure the following
items.

1. Measure the coil bisection of the relay and

check whether it works.
2. Measure the apex bisection for open circuit.
Category Voltage of coil
Judge
terminal
C-NO:SHORT
3-contact DC 12V(Operation)
C-NC:OPEN
terminal Relay C-NO:OPEN
DC 0V(Standstill)
C-NO:SHORT
2-contact DC 12V(Operation) SHORT
terminal Relay DC 0V(Standstill) OPEN

Note) C → Common, NO → Normal open, NC → Normal close

3. When it operates as above, it is normal and

when it does not operate, repair the
corresponding relay.

57
 Ref. 3) Check a load

* Unplug the power cord and disconnect the

connector from the main PCB CN70, 71 and
measure the following:

1. Measure resistance between the terminals and

check for malfunctioning of a load and wire
connection.

Measurement Evaluation of mea-

Subordinate terminal surement result
R Defrost heater CN70 ⑤ - ①
F Defrost heater CN70 ⑦ - ①
Comp CN70 ⑨ - ①
Comp-circulation fan CN71 ⑦ - ①
R-Circulation fan CN71 ⑤ - ①
F-Circulation fan CN70 ③ - ①
R-Lamp CN71 ⑨ - ①
F-Lamp CN71 ③ - ①

Ref. 4) Check sensors

* Disconnect the connector from the main PCB

CN30.
* Resistance will be lowered while the
temperature rises due to a NTC type sensor.
1. R sensor measures resistance of CN30
between ②~⑤.
2. Freezer sensor measures resistance of CN30
between ①~⑤.

3. R-defrost sensor measures resistance of CN30 between ④~⑤.

4. F-defrost sensor measures resistance CN30 between ③~⑤.
5. The measured value above is compared to the sensor specification and the temperature table in
speciication found in the manual.

58
 Ref. 5) Check Door S/W

(Refrigerator Bulb)
1. Open the door and check if the freezer lamp
turns on.
2. Press the Door S/W and check if the freezer
lamp turns off.
3. Close the freezer door and repeat 1 and 2 for
refrigerator door.
4. If there is a problem, check lightbulb and door
S/W.
5. Check wire connection.
(Micom signal)
1. Check if CN30 ⑥ and ⑧ is 5V DC after closing the F·R doors.
2. Check if CN30 ⑥ is 0V DC when opening F door.
Check if CN30 ⑧ is 0V DC when opening R door.
3. If there is problem, check door S/W and wire connection.

Ref. 6) Forced Operation and Forced Defrosting

(Forced running)
* This function is used to turn on the comp
and fan immediately regardless of the
temperature of freezer using the test button
on the main PCB.

1. Press the TEST button on the PCB after

removing the main PCB cover in the
machine compartment.
2. Buzzer will sound to indicate the forced
running.

(Forced defrosting)
* This function is used to turn on the
defrosting regardless of defrost time.

1. Press the button during forced running.

Then, R-defrosting is performed.
2. If the button is press during R-defrosting, F-
defrosting is also performed at the same
time.
3. If the button is pressed during R-F
defrosting, test mode is released.
PCB-MAIN ASSY

59
 Ref. 7) Table of temperature sensor according to resistance and voltage conversion.
* Voltage conversion table depends on H/W structure of MICOM port input voltage.
Sensor Short : Micom 0V.
Sensor Open : Micom 5V.

※ Sensor partial pressure resistance 10KΩ

℉)
Temp.(℉ Ω)
Resistance(Ω Voltage(V) ℉)
Temp.(℉ Ω)
Resistance(Ω Voltage(V) Temp.(℉
℉) Ω)
Resistance(Ω Voltage(V)
-43.6 98870 4.541 12.2 21410 3.408 68.0 6013 1.878
-41.8 93700 4.518 14.0 20480 3.360 69.8 5792 1.834
-40.0 88850 4.494 15.8 19580 3.310 71.6 5581 1.791
-38.2 84150 4.469 17.6 18730 3.260 73.4 5379 1.749
-36.4 79800 4.443 19.4 17920 3.209 75.2 5185 1.707
-34.6 75670 4.416 21.2 17160 3.159 77.0 5000 1.667
-32.8 71800 4.389 23.0 16430 3.108 78.8 4821 1.626
-31.0 68150 4.360 24.8 15740 3.057 80.6 4650 1.587
-29.2 64710 4.331 26.6 15080 3.006 82.4 4487 1.549
-27.4 61480 4.301 28.4 14450 2.955 84.2 4329 1.511
-25.6 58430 4.269 30.2 13860 2.904 86.0 4179 1.474
-23.8 55550 4.237 32.0 13290 2.853 87.8 4033 1.437
-22.0 52840 4.204 33.8 12740 2.801 89.6 3894 1.401
-20.2 50230 4.170 35.6 12220 2.750 91.4 3760 1.366
-18.4 47770 4.134 37.4 11720 2.698 93.2 3631 1.332
-16.6 45450 4.098 39.2 11250 2.647 95.0 3508 1.298
-14.8 43260 4.061 41.0 10800 2.596 96.8 3390 1.266
-13.0 41190 4.023 42.8 10370 2.545 98.6 3276 1.234
-11.2 39240 3.985 44.6 9959 2.495 100.4 3167 1.203
-9.4 37390 3.945 46.4 9569 2.445 102.2 3062 1.172
-7.6 35650 3.905 48.2 9195 2.395 104.0 2962 1.143
-5.8 33990 3.863 50.0 8839 2.3462 105.8 2864 1.113
-4.0 32430 3.822 51.8 8494 .296 107.6 2770 1.085
-2.2 30920 3.778 53.6 8166 2.248 109.4 2680 1.057
-0.4 29500 3.734 55.4 7852 2.199 111.2 2593 1.030
1.4 28140 3.689 57.2 7552 2.151 113.0 2510 1.003
3.2 26870 3.644 59.0 7266 2.104 114.8 2429 0.977
5.0 25650 3.597 60.8 6992 2.057 116.6 2352 0.952
6.8 24510 3.551 62.6 6731 2.012 118.4 2278 0.928
8.6 23420 3.504 64.4 6481 1.966 120.2 2206 0.904
10.4 22390 3.456 66.2 6242 1.922

60
11. PCB Circuit Diagram

61
 272, Oseon-Dong, Kwangsan-Gu,
Kwangju-City, Korea, 506-253
TEL : 82-62-950-6193, 6896
FAX : 82-62-950-6829

- This Service Manual is a property of Samsung Electronics Co., Ltd.

Any unauthorized use of Manual can be punished under applicable
International and/or domestic law. -

© Samsung Electronics Co., Ltd.

Refrigerator Division 2004. 02
Printed in Korea