Mitsubishi Electric MR-385S-W-A User manual

Changes for the Better
Models MR-385S-W-A
MR-385S-ST-A
MR-385SL-W-A
MR-385SL-ST-A
MR-420S-W-A
MR-420S-ST-A
MR-455S-W-A
MR-455S-ST-A
CONTENTS
1. SPECIFICATIONS....................................................
2. OUTLINES AND DIMENSIONS..................................
3. WIRING DIAGRAM....................................................
4. REFRIGERANT CIRCUIT...........................................
5. NAME OF THE PARTS...........................................
6. TROUBLE SHOOTING..............................................
6.1 TROUBLE CRITERION OF MAIN PARTS.......
6.2 HOW TO CHECK P.C.BOARDS......................
6.3 TEST POINT DIAGRAM OF
MAIN CONTROL BOARD..............................
6.4 MULFUNCTION DISPLAY AND CHECKING
POINT...........................................................
6.5 IMPORTANCE DETAIL OF FAULT ANALYSIS.
7. DISASSEMBLY INSTRUCTIONS.................................
8. PARTS LIST...............................................................
1
7
10
11
13
14
14
16
17
18
19
20
23
MR-385S-W-A(NZ)
MR-385S-ST-A(NZ)
MR-385SL-W-A(NZ)
MR-385SL-ST-A(NZ)
MR-420S-W-A(NZ)
MR-420S-ST-A(NZ)
MR-455S-W-A(NZ)
MR-455S-ST-A(NZ)
A……......Australia
A(NZ) .....New Zealand
2006
SERVICE MANUAL
NO.SM-RE-0604
MITSUBISHI
ELECTRIC
HOME REFRIGERATORS

1.1 SPECIFICATIONS
MR-385S-A MR-385SL-A
MR-385S-A(NZ) MR-385SL-A
Power supply 230/240V 50Hz
Total capacity (Gross (AS)) L
Dimensions (HXWXD) mm. 1591 x 685 x 700
Cabinet Acrylic resin coated steel
Food liner ABS resin
Cabinet Foamed cyclopenthane
Freezer door Foamed cyclopenthane
Refrigerator door Foamed cyclopenthane
Cooling system Freezer Forced air convection
Refrigerator Surround cooling,multi air flow,front air flow
Evaporator Fin and tube type
Condenser Concealed type
Defrost system Automatic (Heater defrost)
Drain Automatic (drainage)
Temperature control system Automatic control
Refrigerator room light 240V 15W (E12)
Ice tray 1 pc.
Ice box 1 pc.
Freezer pocket 2 pcs.
Slide chilled case 1 pc.
Crystal shelf (F) 1 pc.
Crystal shelf (R) 3 pcs.
Free pocket 1 pc.
Egg rack 2 pcs.
Adjust pocket 2 pcs.
Bottle pocket 2 pcs.
Vegetable case 1 pc.
Tray V 1 pc.
Drain pan 1 pc.
Bottle stopper 1 pc.
Weight Unit kg 70
Shipping kg 76
- 1 -
Insulation
Accessories
385 (F : 130 R : 255)
1 SPECIFICATIONS

MR-420S-A
MR-420S-A(NZ)
Power supply 230/240V 50Hz
Total capacity (Gross (AS)) L
Dimensions (HXWXD) mm. 1696 x 685 x 700
Cabinet Acrylic resin coated steel
Food liner ABS resin
Cabinet Foamed cyclopenthane
Freezer door Foamed cyclopenthane
Refrigerator door Foamed cyclopenthane
Cooling system Freezer Forced air convection
Refrigerator Surround cooling,multi air flow,front air flow
Evaporator Fin and tube type
Condenser Concealed type
Defrost system Automatic (Heater defrost)
Drain Automatic (drainage)
Temperature control system Automatic control
Refrigerator room light 240V 15W (E12)
Ice tray 1 pc.
Ice box 1 pc.
Freezer pocket 2 pcs.
Slide chilled case 1 pc.
Crystal shelf (F) 1 pc.
Crystal shelf (R) 3 pcs.
Free pocket 1 pc.
Egg rack 2 pcs.
Adjust pocket 2 pcs.
Bottle pocket 2 pcs.
Vegetable case 1 pc.
Tray V 1 pc.
Drain pan 1 pc.
Bottle stopper 1 pc.
Weight Unit kg 74
Shipping kg 81
- 2 -
Insulation
Accessories
420 (F : 130 R : 290)

MR-455S-A
MR-455S-A(NZ)
Power supply 230/240V 50Hz
Total capacity (Gross (AS)) L
Dimensions (HXWXD) mm. 1806 x 685 x 700
Cabinet Acrylic resin coated steel
Food liner ABS resin
Cabinet Foamed cyclopenthane
Freezer door Foamed cyclopenthane
Refrigerator door Foamed cyclopenthane
Cooling system Freezer Forced air convection
Refrigerator Surround cooling,multi air flow,front air flow
Evaporator Fin and tube type
Condenser Concealed type
Defrost system Automatic (Heater defrost)
Drain Automatic (drainage)
Temperature control system Automatic control
Refrigerator room light 240V 15W (E12)
Ice tray 2 pcs.
Ice box 1 pc.
Freezer pocket 2 pcs.
Slide chilled case 1 pc.
Crystal shelf (F) 1 pc.
Crystal shelf (R) 4 pcs.
Free pocket 1 pc.
Egg rack 2 pcs.
Adjust pocket 3 pcs.
Bottle pocket 2 pcs.
Vegetable case 1 pc.
Tray V 1 pc.
Drain pan 1 pc.
Bottle stopper 1 pc.
Weight Unit kg 78
Shipping kg 86
- 3 -
Insulation
Accessories
454 (F : 130 R : 324)

1.2 ELECTRICAL PARTS SPECIFICATION
MR-385S-A MR-385SL-A
MR-385S-A(NZ) MR-385SL-A
Model
Power supply
Compressor Rated input W
Starting current A
Running current A
Winding resistance (A.T. : 20 oC)
PTC RELAY
Model
Motor protector Ambient temperature oC
Time Sec.
Current A
Running capacitor
Capillary tube mm.
Dehydrant Molecular sieve g
Refrigerant HFC. 134a g
Defrosting control Defrosting timer
Defrost finish oC
Thermal fuse oC
Heater Defrost heater
Deodorition
Model
Type
Number of poles
Input W
Revolution r.p.m
Model Freezer Refrigerator (MM1-6177)
Dial position ON OFF OPEN SHUT
Warmer oC-13.7 -19.0 - 3.5
Normal oC-16.9 -22.9 MAX 5.0 -1.0 + 1.5
Colder oC-20.4 -27.5 - -12.5
Fan motor
Temperature control
- 4 -
DG57C96RAW5
106/108(220/240V 50Hz)
7.38/8.01(220/240V 50Hz)
0.57/0.55(220/240V 50Hz)
18.2 Ω(Main) / 17.7 Ω(Aux)
PTH7M330MD2
5TM181NHBYY
Less than 10.2/12 (220/240V 50Hz)
2520 + 200 / 2580+200 (220/240V 50Hz)
2p
25
16 MAX
5.4
4µF 400VAC
Single phase
∅1.8 X ∅0.7 X 2350
10
384 Ω(240V 150W)
Filter
220/240V 50Hz
UDVH15MA1H
145
Control board
Thermister 14 + 1.5
73

MR-420S-A
MR-420S-A(NZ)
Model
Power supply
Compressor Rated input W
Starting current A
Running current A
Winding resistance (A.T. : 20 oC)
PTC RELAY
Model
Motor protector Ambient temperature oC
Time Sec.
Current A
Running capacitor
Capillary tube mm.
Dehydrant Molecular sieve g
Refrigerant HFC. 134a g
Defrosting control Defrosting timer
Defrost finish oC
Thermal fuse oC
Heater Defrost heater
Deodorition
Model
Type
Number of poles
Input W
Revolution r.p.m
Model Freezer Refrigerator (MM1-6177)
Dial position ON OFF OPEN SHUT
Warmer oC-13.7 -19.0 - 3.5
Normal oC-16.9 -22.9 MAX 5.0 -1.0 + 1.5
Colder oC-20.4 -27.5 - -12.5
Fan motor
Temperature control
- 5 -
DG66C11RAW5
117/118(220/240V 50Hz)
8.05/8.83(220/240V 50Hz)
0.71/0.66(220/240V 50Hz)
15.4 Ω(Main) / 17.7 Ω(Aux)
PTH7M330MD2
5TM205NHBYY
Less than 10.2/12 (220/240V 50Hz)
2520 + 200 / 2580+200 (220/240V 50Hz)
2p
25
16 MAX
6.0
4µF 400VAC
Single phase
∅1.8 X ∅0.7 X 2350
10
384 Ω(240V 150W)
Filter
220/240V 50Hz
UDVH15MA1H
145
Control board
Thermister 14 + 1.5
73

MR-455S-A
MR-455S-A(NZ)
Model
Power supply
Compressor Rated input W
Starting current A
Running current A
Winding resistance (A.T. : 20 oC)
PTC RELAY
Model
Motor protector Ambient temperature oC
Time Sec.
Current A
Running capacitor
Capillary tube mm.
Dehydrant Molecular sieve g
Refrigerant HFC. 134a g
Defrosting control Defrosting timer
Defrost finish oC
Thermal fuse oC
Heater Defrost heater
Deodorition
Model
Type
Number of poles
Input W
Revolution r.p.m
Model Freezer Refrigerator (MM1-6177)
Dial position ON OFF OPEN SHUT
Warmer oC-13.7 -19.0 - 3.5
Normal oC-16.9 -22.9 MAX 5.0 -1.0 + 1.5
Colder oC-20.4 -27.5 - -12.5
Temperature control
- 6 -
Less than 10.2/12 (220/240V 50Hz)
2520 + 200 / 2580+200 (220/240V 50Hz)
DD66C13RAW5
127/131(220/240V 50Hz)
8.3/9.1(220/240V 50Hz)
Fan motor
UDVH15MA1H
Single phase
2p
4µF 400VAC
0.63/0.61(220/240V 50Hz)
12 Ω(Main) / 28.7 Ω(Aux)
Filter
∅1.8 X ∅0.7 X 2350
10
145
Control board
384 Ω(240V, 150W)
220/240V 50Hz
Thermister 14 + 1.5
73
25
16 MAX
6.0
PTH7M330MD2
5TM205NHBYY

Unit : mm
MR-385S-A
MR-385S-A(NZ)
MR-385SL-A
MR-385SL-A(NZ)
- 7 -
2 OUTLINES AND DIMENSIONS
20
685
20
1334
454
50
100
1591
700
REQUIRED SPACE FOR INSTALLATION
1950
PLUG CORD LENGTH
568
685
81591
942
73

Unit : mm
MR-420S-A
MR-420S-A(NZ)
- 8 -
PLUG CORD LENGTH
REQUIRED SPACE FOR INSTALLATION
20685
20
1334
454
50
100
1696
700
1950
568
685
81696
1047
73

Unit : mm
MR-455S-A
MR-455S-A(NZ)
- 9 -
PLUG CORD LENGTH
REQUIRED SPACE FOR INSTALLATION
20685
20
1334
454
50
100
1806
700
1950
568
685
81806
1157
73

(SKELETON WIRING DIAGRAM)
MR-385S-A
MR-385S-A(NZ)
MR-385SL-A
MR-385SL-A(NZ)
MR-420S-A
MR-420S-A(NZ)
MR-455S-A
MR-455S-A(NZ)
(ACTUAL WIRING DIAGRAM)
3 WIRING DIAGRAM
- 10 -

MR-385S-A MR-385SL-A MR-420S-A
MR-385S-A(NZ) MR-385SL-A(NZ) MR-420S-A(NZ)
- 11 -
4 REFRIGERANT CIRCUIT

MR-455S-A
MR-455S-A(NZ)
- 12 -

MR-385S-A MR-420S-A
MR-385S-A(NZ) MR-420S-A(NZ)
MR-385SL-A MR-455S-A
MR-385SL-A(NZ) MR-455S-A(NZ)
- 13 -
5 NAMES OF PARTS

6.1 TROUBLE CRITERION OF MAIN PARTS
MR-385S-A MR-385SL-A MR-420S-
A
MR-455S-A
MR-385S-A(NZ) MR-385SL-A(NZ) MR-420S-A(NZ) MR-455S-A(NZ)
Compressor
Measure the resistance with a tester.
(Ambient temperature:Room temperature 15oC ~ 25oC)
In the control
panel of the
Measure the resistance with a tester. refrigerator
compartment
Model
Measure the resistance with a tester.(Ambient temperature:Room temperature 15oC ~ 25oC)
PTC RELAY PTH7M330MD2
Measure the resistance with a tester.
(Ambient temperature:Room temperature 15oC ~ 25oC)
Normal
As PTC Relay has been heated while refrigerator is running be sure
to measure the resistance after the thermistor has got cool enough.
Motor
protector
Abnormal
(faulty)
A 7.38/8.01(220/240V 50Hz)
0.57/0.55(220/240V 50Hz)
Normal
MR-385S/SL
Rated input
MR-420S,455S
6 TROUBLE SHOOTING
120 + 5oC
400VAC
Run capacitor
Opened (∞ Ω )
W
the machine
chamber at the
Rated input
- 14 -
Connected
Point
Model
Normal
A
bnormal(faulty)
Less than 1Ω
rear side of
Opened (∞ Ω )
69 + 9oC
the frame
Starting current
Running current A
chamber at the
Compressor in
the machine
chamber at the
rear side of
the machine
Components/
Part Name
Model
Parts Mounted
Position
Check Method and Criterion
DG57C96RAW5
MR-420S,455SMR-385S/SL
DG66C11RAW5
Compressor in
the frame
Compressor in
rear side of
the frame
Close
Open
Normal
Main wiring
Auxilliary wiring 17.7 Ω (Approx.)
5TM181NHBYY 5TM205NHBYY
Abnormal(faulty)
Opened(∞ Ω )
or
Short (0Ω)
117/118(220/240V 50Hz)
8.05/8.83(220/240V 50Hz)
0.71/0.66(220/240V 50Hz)
106/108(220/240V 50Hz)
18.2 Ω(Approx.)
17.7 Ω (Approx.)
15.4 Ω(Approx.)
A
bnormal(faulty)
Opened (∞ Ω ) or Short (0Ω)
33 Ω(Approx.)
Short (0Ω)
MR-420S,455SMR-385S/SL
69 + 9oC
120 + 5oC
Auxilialy
wiring
Main
wiring
5
6
3
2
5
6
2
3

In fan grill of the
freezer compartment.
Measure the resistance with a tester.
(Ambient temperature:Room temperature 15oC ~ 25oC)
In the drip tray under
the evaporator of the
freezer compartment
Measure the resistance with a tester.
(Ambient temperature:Room temperature 15oC ~ 25oC)
Resistance measured under Defrost thermistor
the ambient temperature fro
m
(k
Ω
)at the muffler
-50: to +50: of evaporator
in freezer compartment.
1. 200" to 500k"
............normal Freezer thermistor at
2. Out of the above range fan grille of freezer
............abnormal compartment.
Out air thermistor
under hinge cover
Thermistor Check Procedure
Thermistor resistance will vary
with the change of temperature.
Take the temperature around the thermistor,
and then measure resistance using a tester.
The relation of resistance and temperature is as shown on
the above graph.
- 15 -
Short (0Ω)
Rated input 150 W
Operation method Power ON after defrosting
(14 + 1.5oC or more)
Thermistor
Opened ( ∞ Ω )
Defrost
Heater
Abnormal (faulty)Normal
384Ω(Approx.)
Abnormal(faulty)
Refrigerator
fan motor
560+ 10% ( Ω)
UDVH15MA1H
Model
Normal
Check Method and Criterion Parts Mounted Position
Components/
Part Name
Resistance
-20 20 30 -10 010
30
20
15
10
5
0
25
35
Thermistor resistance valves against
temperature
Temperature
Outside air thermistor
Freezer
thermistor,
Defrost
thermistor
Inner
thermistor

6.2 HOW TO CHECK P.C BOARDS
MR-385S-A MR-385SL-A MR-420S-A MR-455S-A
MR-385S-A(NZ) MR-385SL-A(NZ) MR-420S-A(NZ) MR-455S-A(NZ)
(1) Precautions
Unplug unit before checking
If the controller P.C. board box is opened with the refrigerator inside
cooled, dew will form on the control board, causing trouble such as
poor insulation.
The following cares must be taken when servicing.
1. Be sure to unplug the power cord before servicing.
2. Wipe away droplets on the control board box with dry cloth,
and dry it up before setting a new controller P.C board.
(2) How to check the controller P.C board and vicinity.
The control board box can be checked without opening the box.
Measure the voltage and resistance using 8 connectors outside
the box. How to check with connectors
1. Check for 230/240V output during power on. POWER ON
Make the pin No.7,9 of the 9 pins white connector as a common pin,
and measure the voltage between the common pin and
another pin.
Make sure that 230/240V is output
Note: The room light always has 230/240V.
2. Check for "Thermistor" output during power on.
5 pins white connecto
r
Make the pin No.1 of the 5 pin white connector as a
common pin, and measure the voltage between the common
pin and another pin.
Make sure that 2-3 VDC is output.
POWER OFF
3.Check for weak current wiring during power off
5 pins white connecto
r
Remove the connector, and measure the resistance across
-No.1 pin and No.2 pin to confirm the continuity for DEF
thermistor.
-No.1 pin and No.3 pin to confirm the continuity for the
Freezer thermistor.
- 16 -

6.3 TEST POINT DIAGRAM OF MAIN CONTROL BOARD
MR-385S-A MR-385SL-A MR-420S-A MR-455S-A
MR-385S-A(NZ) MR-385SL-A(NZ) MR-420S-A(NZ) MR-455S-A(NZ)
- 17 -

6.4 Malfunction Display and Checking points.
6.4.1 ) Malfunction display will use LED for show self-check
6.4.2 ) Fucntion display
Lighting mode (time amount) will blink by on 3 min. as fixed times amount after that will off 5 seconds, which will repeat as cycle sample.
6.4.3 ) Repairing and check point
* A the case below , if the analysis result has malfunction over 2 points and will express in the list has more importance.
Function display Cause Analysis result Check point Corrective Priority Repairing
2. Check the resistance of thermistor Change part
2. Check the resistance of thermistor Change part
2. Check the resistance of defrost heater Change part
3. Check the resistance of temp. fuse Change part
Caution
1. Before plug in the AC power , Be ensure the comp had been off more than 20 min.
Fault trouble of defrost heater
Open circuit or short
circuit case
Open circuit or short
circuit case
- 18 -
2. The consider short circuit or open circuit of thermistor , resistance of open circuit is
∞
Ω
, resistance of short circuit is 0 Ω
1. Check connector of control PCB CN5 ,
relay connector 6 pin
1. Check connector of control PCB CN5 ,
relay connector 2 pin
Improve in contact
LED display self - check
Malfunction display
Lighting mode
1 time
2 times
3 times Defrost unfinished
with in 2 hours
Fault trouble of defrost thermistor
Fault trouble of freezer thermistor
2
1
Improve in contact
Improve in contact
1. Check connector of control PCB CN1 ,
relay connector temp. fuse
3
ON
OFF
5 Sec.
Cycle
2 times1 time
Cycle Cycle Cycle
5 Sec. 5 Sec. 5 Sec.
1 time
1 time1 time 2 times 2 times 2 times

6.5 Importance detail of fault analysis
6.5.1 Flow chart of self - check
1) Self - check monitor circuit
For show the fault condition of refrigerator and clarify point. Therefore, self - check monitor control is provided
that are able to monitor No. of blinking condition with electric circuit and electric part . Before disconnect power plug please
confirm LED self - check .
"CONTROL PANEL"
LED show shelf - check
Caution
1. As the part list below couldn't analysis by self - check , then
please check by reference to trouble shooting page.
- Dilapidation of door switch ,refrigerator room and freezer room.
- Dilapidation of compressor and fan motor .
2. If have malfunction when supply the power . Compressor and
fan motor will not operate 20 minutes.
2) Interval of self check analysis
- Troubles of thermistor : will check always.
- Trouble of defrost heater : will just analyse during defrost display only.
(The period checking will analyse the defrost circuit after connect the plug 2 hours )
- 19 -
Refrigerator
plug connect?
Connect power plug
Self - check
Mal Function Display
(No .of blinking)
No change on display Normal operation
Check the fault point as
malfunction list
Disconnect power plug
Repair the macfunction cause
Connect power plug
No
Yes
Yes
No