Samsung SMH7178STD/XAA User manual

Fast Track Troubleshooting
Publication # nwSMH7188 Creation Date 07/29/2012
Model:
SMH7178STD/XAA
SMH7178STE/XAA
Samsung 'Microwave' Diagnostic Code Quick Guide
Failure Code Cause
E-11 Open
E-12 Short
E-13 T1 Max Time Error
E-14 Dry Up / No Load
Error Code Gas Sensor Error Case (E-1X)
E-21 Open
E-22 Short
E-23 T1 Max Time Error (Preheating not completed)
E-24 Over temperature error
E-25 Abnormal temperature is sensed at Micro Cook
E-26 Temp is not over the fixed AD in first 3 minutes after heater starts.
Error Code Temp Sensor Error Case (E-2X)
E-31 Open (When value of HEX is above “FF” for 5 seconds)
E-32 Short
E-33 The initial value of HEX is under “14” for 30 seconds while a weight
sensor in operation.
E-34 The initial value of K calculated by a weight
sensor is above and under “±28” as value of HEX.
E-35 The value of A is “-” as a weight sensor calculates.
E-36 In case the door opens during sensor cooking.
Error Code Gas Sensor Error Case (E-1X)
E-41 Open
E-42 Short
E-43 T1 Max Time Error
E-44 Dry Up
E-45 Cooling Error (3minutes)
E-46 Primary Open Error(3minutes)
E-47 The door opens during cooking
Error Code Easy/PH Sensor Error Case (E4)
E-51 Open (Sense Failure)
E-53 Read/Write Error
E-54 Zero not to be set Error Code EEPROM Error Case (E-5X)
E-61 Open
E-62 Short
E-63 T1 Max Time Error Error Code Humidity Sensor Case (E-6X)
-SE- Key Short Error (10 seconds)
E-01 Door opens when the door should not be opened.
E-02 Cooking Time Setting Over Error (MWO)
E-03 Cooking Time Setting Over Error (Grill)
E-04 Cooking Time Setting Over Error (Convection)
E-05 Cooking Time Setting Over Error (Combination)
E-06 It fails to sense that the swing heater has stopped for 20 seconds
during cooking.
E-08 In case function of MWO starts with spit inserted into cavity inside.
E-09 The damper is not set to be positioned for 2 minutes.
Error Code Others (E-0X, Letter)
IMPORTANT SAFETY NOTICE – “For Technicians Only” This service data sheet is
intended for use by persons having electrical, electronic, and mechanical experience
and knowledge at a level generally considered acceptable in the appliance repair trade.
Any attempt to repair a major appliance may result in personal injury and property
damage. The manufacturer or seller cannot be responsible, nor assume any liability for
injury or damage of any kind arising from the use of this data sheet.

CN05 Gas Sensor
3-4 5vdc
CN202 Pwr & Relay
1-(CN201-1) Main
3-(CN201-1) TT
5-(CN201-1) Vent Low
7-(CN201-1) Vent High
9-(CN201-1) Vent Boost
Main PCB
CN201 Relay, Lamp, SMPS
1 Line 1
3-1 RY202 In Rush Relay Neutral Contact
5-1 RY206 Bright Lamp Relay Neutral Contact
5-1 RY205 Night Lamp Relay Neutral Contact
7-1 RY207 Louver
RY203
Power
High Relay
RY209
Fan
RY208
TT
RY201
Main
Relay
RY05
Night
Relay
RY206
Bright
Relay
RY202 In
Rush Relay
Door Interlock Ass’y
CN401 Door Connector
1 Door sw
3 Door sw
3-5 12vdc
4-5 5vdc
The fuse is located on the noise filter.
1. Disconnect power and remove grille and Assembly
Control Box.
2. Replace the fuse.
3. When 20A fuse blows out by the operation of interlock
monitor switch failure, replace the primary interlock
switch, secondary interlock switch, door sensing switch,
interlock monitor switch and power relay.
4. When the above four switches operate properly, check
if any other part such as the control circuit board, blower
motor or high voltage transformer is defective.
CN01
1) KEY OUT-1
2) KEY OUT-2
3) KEY OUT-3
4) KEY OUT-4
5) KEY OUT-5
6) KEY OUT-6
7) KEY OUT-7
8) KEY OUT-8
9) KEY OUT-9
10) KEY IN-1
11) KEY IN-2
12) KEY IN-3
13) KEY IN-4
14) KEY IN-5
15) KEY IN-6
16) KEY IN-7
RY207
Louver
RY204
Power Low
Relay

WARNING: It is critical to route wires and
wire harness identical to the way they were,
to prevent electromagnetic interference caus-
ing possible fault codes.
Procedure for measurement of microwave energy leakage
1. Pour 275±15cc of 20±5°C(68±9°F) water in a beaker which is
graduated to 600cc, and place the beaker in the center of the oven
2. Start to operate the oven and measure the leakage by using a mi-
crowave energy survey meter.
3. Set survey meter with dual ranges to 2,450MHz.
4. When measuring the leakage, always use the 2 inch spacer cone
with the probe. Hold the probe perpendicular to the cabinet door.
Place the spacer cone of the probe on the door and/or cabinet door
seam and move along the seam. The door viewing window and the
exhaust openings moving the probe in a clockwise direction at a
rate of 1 inch/sec. If the leakage testing of the cabinet door seam is
taken near a corner of the door, keep the probe perpendicular to
the areas making sure that the probe end at the base of the cone
does not get closer than 5 cm to any metal. If gets closer than 5
cm, erroneous readings may result.
5. Measured leakage must be less than 4mW/cm2 after repair and
adjustment.
Maximum allowable leakage is 5mW/cm2. 4mW/cm2 is used to allow
for measurement and meter accuracy.
MicrowaveCookingWattageTest
Safety precautions
High Voltage Warning Do not attempt to
measure any of the high voltages --this in-
cludes the filament voltage of the magnetron.
High voltage is present during any cook cycle.
Before touching any components or wiring,
always unplug the oven and discharge the
high voltage capacitor
Some semiconductor (“solid state”) devices
are easily damaged by static electricity. Such
components are called Electro statically
Sensitive Devices (ESDs). Examples
include integrated circuits and field-effect
transistors. Immediately before handling any
semiconductor components or assemblies,
drain the electrostatic charge from your body
by touching a known earth ground.
Temp Rise Output Temp Rise Out-
put
5194 23 891
6232 24 930
7271 25 969
8310 26 1007
9349 27 1046
10 387 28 1085
11 426 29 1124
12 464 30 1162
13 504 31 1201
14 542 32 1240
15 581 33 1279
16 620 34 1317
17 659 35 1356
18 697 36 1395
19 736 37 1434
20 775 38 1472
21 814 39 1511
22 852 40 1550
Fill a 1000ml plastic room temperature container with cool tap water,
temperature of the water should be 55-65 degrees
Stir water with a thermometer and record the water temperature, remove
thermometer.
Place the container in the center of the lowest shelf or center of the
bottom of the microwave.
For units less than 1550 watts, operate the oven on high for exactly 63
seconds.
Using the thermometer, stir the water to check the temperature of the
water.
Subtract the starting temperature from the final temperature; this will be
the temperature rise.
NOTE: Check line voltage under load, lower line voltage will lower
the power output.
M/W Information
Specifications
M/W Power 1100 Watts
M/W Weight 54.23 Lbs
High Voltage
Transformer
Primary 0.43Ω
Secondary 125-130Ω
Filament 0.0Ω
Motors
Vent Turbo 21Ω
Vent High 45Ω
TT & Stirrer Motors 120Ω
Fan Motor 32-40Ω