Fast Track Troubleshooting
Model:
SMH9207ST/XAA
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.
SUPPORT INFORMATION
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Samsung 'Microwave' Diagnostic Code Quick Guide
Failure Code
Publication # tsSMH9207
Creation Date 2/28/2012
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)
CN05
1) RY-POWER-L
2) RY-POWER-H
3) RY-INRUSH
4) G S
5) RY-BRIG HT
6) KEY7-AD
7) RY-SPARE
8) VFD FILAM ENT1
9) RY-NIG HT
10) VFD FILAM ENT2
11) RY-VENT-H
12) RY-O PTIO N
13) RY-VENT-M
14) -34V
15) RY-V_DO O R
16) G ND
17) BUZZER
18) G ND
19) RY-VENT-L
20) + 5V
21) RY-TT
22) + 5V
23) INT
24) TCO -S
25) RY-M AIN
26) STB
CN03 Gas Sensor
4-3 5vdc
Main PCB
CN04 Door Connector
1 Door sw
3 Door sw
3-5 12vdc
4-5 5vdc
RY02 In
Rush Relay
RY04 Power
Low Relay
RY06
Night
Relay
RY03
Power
High Relay
CN06
1-3 5vdc
RY01
Main
Relay
RY08
TT
RY09
Vent
Low
CN02 Pwr & Relay
1-(CN01-1) Vent High
3-(CN01-1) Vent Mid
5-(CN01-1) Vent Low
7-(CN01-1) TT
9-(CN01-1) Main Relay Contact
RY10
Vent
Mid
RY05
Bright
Relay
RY11
Vent
High
CN01 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
The fuse is located on the noise filter.
1. Disconnect power and remove grille and Assembly
Control Box.
2. Replace the fuse.
Door Interlock Ass’y
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.
L1
L1
N
N
The SMH9207 presents with the symptom of the microwave oven being “DEAD”.
There are no functions available and the oven is incapable of operating at this time. Testing has shown that this problem
can manifest due to a failure of the ASSY PCB MAIN which is located in the microwave ovens Door Assy.
To Troubleshoot this failure, you will need a DVM (Digital Voltage Meter) capable of reading both AC and DC
voltages. Use the Images on page three for reference.
Step 1:

Check that AC voltage is available and present in the microwave oven. Check the input voltage at the Noise
Filter PCB Assy. Check for ≈ 120VAC on both the input and output connectors of the PCB.

If the Voltage is not Present, check the input wire harness, outlet for voltage. Also check that the circuit
breaker of fuse supplying the outlet is not open.

If voltage is present at the input of the Noise Filter board, but not present at the output, check the 20 A,
250VAC fuse on the Board. Replace the fuse or board as necessary.
Note: The wiring diagram in the Service Manual for SMH9207 is incorrect. Page 2 cannot be used to locate connectors and pins due to the mislabeling of the connectors. Please use the provided picture on page 3 for correct connector and pin assignments.
Step 2.: The configuration of this microwave oven differs with the traditional configurations of ovens by Samsung. The
Logic and Control of the microwave oven has been split between 2 (two) boards where in previous models, all functions
are contained on one board. Unfortunately both of the new boards are described a ASSY PCB MAIN. For the purposes
of troubleshooting, we will refer to the 2 boards as follows:
Relay Circuit Board Assy (ASSY PCB MAIN) - Large board located in ASSY Control BOX
Control Circuit Board Assy (ASSY PCB MAIN) - Located in in the ASSY DOOR

Check if AC voltage is present at the Relay Circuit Board assy. (MAIN). Measure for ≈120VAC between
CN01—Pin 1 (B6) and the Neutral line out of the noise filter Board assy. (White wire). If the voltage is not
present check the following:
1. MGT TCO and the Cavity TCO for open conditions. Remove power form the microwave oven. Using an ohmmeter, check for continuity from the noise filter L voltage output (Black wire) to CN01—
pin 1. If open, check each TCO individually with an ohmmeter and replace as necessary.

If the AC voltage is present at CN01-Pin1, check for the presence of the Main Relay Control Signal (RYMAIN) from the Control Circuit Board which is located in the Door Assy.
1. Using a DC Multi-meter, check for a signal voltage at connector CN05 on the MAIN PCB. Check
Pin 25. The signal should read:

≈3.5 vdc
with the door closed.

≈4.5 to 5 vdc
with the door open.
Use the metal ASSY Bracket for DC gnd.

If the signal is not present, this indicates a failure of the Control Circuit Board.(Also called MAIN). A final
check is to look for 5 vdc at CN05—pins 22 and 20. If the 5 vdc is not present, the Control Circuit PCB has
failed. The 5 vdc is created on the relay bd., but is loaded down and won’t be present.
Parts:
Control Circuit Board Assy. Please order:
DE92-02135A
ASSY PCB MAIN
Relay Circuit Board Assy. This Board is not available as a service part. Please order:
DE94-02097A
The board is part of this assembly.
ASSY CONTROL BOX
Microwave Cooking Wattage Test
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.
Temp Rise
Output
Temp Rise
Out-
5
194
23
891
6
232
24
930
7
271
25
969
8
310
26
1007
9
349
27
1046
10
387
28
1085
11
426
29
1124
12
464
30
1162
NOTE: Check line voltage under load, lower line voltage will lower
the power output.
13
504
31
1201
14
542
32
1240
Procedure for measurement of microwave energy leakage
15
581
33
1279
16
620
34
1317
17
659
35
1356
18
697
36
1395
3. Set survey meter with dual ranges to 2,450MHz.
19
736
37
1434
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 if gets closer than 5
cm, erroneous readings may result.
20
775
38
1472
21
814
39
1511
22
852
40
1550
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 microwave energy survey meter.
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.
Safety precautions
Some semiconductor (“solid state”) devices
are easily damaged by static electricity. Such
components are called Electrostatically
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.
M/W Information
M/W Power
1100 Watts
M/W Weight
52.7 Lbs
Primary
0.43Ω
Secondary
120-125Ω
Filament
Vent Turbo
Vent Normal
0.0Ω
30Ω
67Ω
Vent High
59Ω
TT & Stirrer Motors
120Ω
Fan Motor
32-40Ω
Specifications
High Voltage Transformer
Motors
High Voltage Warning Do not attempt to
measure any of the high voltages --this includes 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
WARNING: It is critical to route wires and
wire harness identical to the way they were,
to prevent electromagnetic interference causing possible fault codes.