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Samsung Electronics

6-2

Troubleshooting

SYMPTOM

CAUSE

CORRECTIONS

Oven lamp and fan motor turn on

1. Misadjustment or loose wiring 

Adjust door and latch switches.

of primary latch switch

2. Defective primary latch switch

Oven can program but timer

1. Open or loose wiring of secondary 

Adjust door and interlock switches.

does not start.

interlock switch

2. Off-alignment of primary interlock
3. Defective secondary interlock S/W

Microwave output is low;.

1. Decrease in power source voltage.

Consult electrician.

Oven takes longer time to

2. Open or loose wiring of magnetron

cook food.

filament circuit. (Intermittent oscillation))

3. Aging of magnetron

Fan motor turns on when plugged in

Loose wiring of door sensing switch

Check wire of door sensing switch.

Oven does not operate and return

Defective Ass'y PCB

Replace PCB main.

to the plugged in mode.

Loud buzzing noise can be heard.

1. Loose fan and fan motor

Tighten screws of fan motor.

2. Loose screws on H.V.Transformer

Tighten screws of H.V.Transformer.

3. Shorted H.V.Diode

Replace H.V.Diode.

Turntable motor does not rotate.

1. Open or loose wiring of turntable motor.

Replace turntable motor.

2. Defective turntable motor.

Oven stops operation during cooking

1. Open or loose wiring of primary 

Adjust door and latch switches.

interlock switch

2. Operation of thermal cutout(Magnetron)

Sparks

1. Metallic ware or cooking dishes

Inform the customer.

touching on the oven wall.

2. Ceramic ware trimmed with gold or

Do not use any type of cookware with

silver powder also causes sparks.

metallic trimming.

Uneven cooking

Uneven intensity of microwave due to

Wrap thinner parts of the food with 

its characteristics.

aluminum foil.
Use plastic wrap or cover with a lid.
Stir once or twice while cooking
foods such as soup, cocoa, or milk.

Noise from the turntable motor

Noise may result from the motor.

Replace turntable motor.

when it starts to operate.

6-1 Electrical Maltunction(continved)

Summary of Contents for M1774

Page 1: ...EManual MICROWAVE OVEN CONTENTS 1 Precaution 2 Specifications 3 Operating Instructions 4 Disassembly and Reassembly 5 Alignment and Adjustments 6 Troubleshooting 7 Exploded Views and Parts List 8 PCB Diagrams 9 Schematic Diagrams ...

Page 2: ...k switches interlock monitor switch 12 If the fuse is blown by the Interlock Monitor Switch Replace all of the following at the same time Primary and secondary switches as well as the Interlock Monitor Switch The correct adjustment of these switches is described elsewhere in this manual Make sure that the fuse has the correct rating for the particular model being repaired 13 Design Alteration Warn...

Page 3: ...es 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 See Figure 1 1 2 The high voltage capacitor remains charged about 30 seconds after disconnection Short the negative terminal of the high voltage capacitor to to the oven chassis Use a screwdrive...

Page 4: ...ONSUMPTION MICROWAVE 1 250W OUTPUT POWER FROM 100 TO 850W IEC 705 TEST PROCEDURE OPERATING FREQUENCY 2 450MHz MAGNETRON OM75SH 31 COOLING METHOD COOLING FAN MOTOR OUTSIDE DIMENSIONS 489 W x 275 H x 370 D 2 2 Comparison Chart AUTO REHEAT O AUTO COOK O POWER LEVEL O TIME SETTING AND WEIGHT O AUTO DEFROST O DEODORIZATION O ...

Page 5: ...t Button Deodorization Button Auto Reheat Cook Selection 3 Operating Instructions 3 1 Control Panel Samsung Electronics 3 1 3 2 Features External Views Door Ventilation Holes Light Safety Interlock Holes Control Panel Roller Ring Coupler Glass Plate Door Latches 489mm 275mm 370mm ...

Page 6: ...make sure that its antenna does not hit any adjacent parts or it may be damaged NOTE2 When replacing the magnetron be sure to remount the magnetron gasket in the correct position and make sure the gasket is in good condition 1 Discharge the high voltage capacitor 2 Disconnect all the leads 3 Remove the mounting bolts 4 Reconnect the leads correctly and firmly 4 2 Replacement of High Voltage Transf...

Page 7: ...er hinge Then remove the door assembly Insert flat screwdriver into the gap between Door E and Door C to remove Door C Be careful when handling Door C because it is fragile Following the procedure as shown in the figure insert and bend a thin metal plate between Door E and Door A until you hear the tick sound Insertion depth of the thin metal plate should be 0 5mm or less 4 3 4 Removal of Key Door...

Page 8: ...hen replacing the drive motor be sure to remount it in the correct position 8 Connect all the leads to the drive motor 9 Screw the deive motor cover to the base plate with a screw driver 10 Remount the coupler in the correct position 4 4 Replacement of Fuse 4 5 Replacement of Drive Motor Disassembly and Reassembly Screw Drive Motor Cover Base Plate Drive Motor After replacement of the defective co...

Page 9: ...emove the screw securing the ground tail of the keyboard 1 Pull the lever end of the plastic fastener and remove the Flexible Printed Circuit FPC of membrane panel 2 Remove screws securing the control circuit board 3 Lift up the control circuit board from the Ass y control box 4 When reconnecting the FPC connector make sure that the holes on the connector are properly engaged with the hooks on the...

Page 10: ...nt terminal and magnetron case should read open 1 The low voltage transformer is located on the control circuit board 2 Remove the low voltage transformer from the PCB Ass y and check continuity 3 Normal resistor reading is shown in the table Filament Terminals Secondary Terminal Primary Terminals Secondary Approx 114W Filament Approx 0W Primary Approx 1 47W Terminals Resistance 1 2 Input 1 000W 3...

Page 11: ...ust the Latch Body by moving it so that the oven door will not have any play in it Check for play in the door by pulling the door assembly Make sure that the latch keys move smoothly after adjustment is completed Completely tighten the screws holding the Latch Body to the oven assembly 4 Reconnect to Monitor switch and check the continuity of the monitor circuit and all latch switches again by fol...

Page 12: ... is finished stir the water again with the thermometer and measure the temperature T2 5 Subtract T1 from T2 This will give you the water temperature rise DT 6 The output power is obtained by the following formula 7 Normal temperature rise for this model is 9ûC to 11ûC at HIGH NOTE 1 Variations or errors in the test procedure will cause a variance in the temperature rise Additional power test shoul...

Page 13: ...ir of a radiarion preventing device make a repair record for the measured values and keep the data 2 If the radiation leakage is more than 4 mW cm2 after determining that all parts are in good condition functioning properly and the identical parts are replaced as listed in this manual notift that fact to CENTRAL SERVICE CENTER 5 13 2 At least once a year have the microwave energy survey meter chec...

Page 14: ...witch 3 Defective monitor switch NOTE1 4 Shorted HVCapacitor 5 Shorted HVTransformer NOTE2 NOTE 1 All of these switches must be replaced at the same time refer to adjustment instructions Check continuity of power relay contacts and if it has continuity replace power relay also NOTE 2 When HVTransformer is replaced check diode and magnetron also Oven does not accept 1 Key input is not in Sequence R...

Page 15: ...noise can be heard 1 Loose fan and fan motor Tighten screws of fan motor 2 Loose screws on H V Transformer Tighten screws of H V Transformer 3 Shorted H V Diode Replace H V Diode Turntable motor does not rotate 1 Open or loose wiring of turntable motor Replace turntable motor 2 Defective turntable motor Oven stops operation during cooking 1 Open or loose wiring of primary Adjust door and latch swi...

Page 16: ...d Parts List 7 1 Exploded Views 7 1 M1 M28 M27 M21 M29 M22 M23 M2 M24 M25 M26 M15 M14 M16 M18 M19 M20 M3 M4 M5 M6 M7 M8 M9 M10 M12 M13 M11 M17 D1 D2 D3 D4 D5 D6 D10 D7 D9 D8 B1 B2 B2 B3 B4 NC NO COM C2 C1 C3 C7 C5 C8 C6 C10 C13 C11 C9 C12 C4 ...

Page 17: ...EX 1 M13 DE67 60075A COUPLER PPS 7G BRN M97G45 1 M14 DE71 60457A COVER AIR PP T1 7 W115 5 L150 WHT 3RD W0 1 M15 DE26 00014A TRANS H V SHV 175EC 230V50HZ 2275V 3 40V DY 1 M16 DE61 50106A BRACKET HVC SECC T0 8 W31 L125 8 1 M17 2501 001016 C OIL 950nF 2 1KV BK 35x54x80 20mm 1 M18 DE59 40001A DIODE H V HVR 1X 32B 12 1 M19 DE91 70061B ASSY H V FUSE THV060T 0750 H 5KV0 75A RED 1 M20 DE61 40017A FOOT PP ...

Page 18: ...H BODY POM F20 02 50G RE 330 1 B 2 3405 000178 SWITCH MICRO 250V 15A 200gf SPST NO 2 B 3 3405 000175 SWITCH MICRO 250V 15A 200gf SPST NO 1 B 4 DE66 90054A LEVER SWITCH POM F20 02 15G NTR RE 330 1 7 5 Body Latch Parts List Ref No Parts No Description Specification Q ty Remarks C 1 DE71 00005A COVER PANEL ABS HR0370 P WHT M1774 XEF 1 C 2 DE66 00013A BUTTON SELECT A ABS HR0370 P WHT 1 C 4 DE67 00003A...

Page 19: ...PLATE DE60 10082H SCREW A 2S 4X12 TOOTHED 1 C BLOWER DE60 10082H SCREW A 2S 4X12 TOOTHED 2 C BOX DE60 10082H SCREW A 2S 4X12 TOOTHED 4 O PANEL DE60 10098A SCREW ASSY TAP TITE PH TC M4X8 SWRCH18A ZPC2 GLD W 1 CAVITY TCO DE60 10098A SCREW ASSY TAP TITE PH TC M4X8 SWRCH18A ZPC2 GLD W 2 D MOTOR DE60 10098A SCREW ASSY TAP TITE PH TC M4X8 SWRCH18A ZPC2 GLD W 2 MGT TCO DE60 30016A NUT FLANGE M4 MSWR10 2 ...

Page 20: ...8 P C B Diagrams 8 1 P C B Diagrams Samsung Electronics 8 1 ...

Page 21: ...MIC MLC AXIAL 1nF 10 50V Y5P TP 1 9x3 5 3 C014 C015 C016 P20 2202 000780 C CERAMIC MLC AXIAL 100nF 80 20 50V Y5V TP 3 5x1 4 C004 C006 C007 C010 P21 2401 000151 C AL 1000uF 20 25V GP TP 12 5x20 5 1 C001 P22 2401 000244 C AL 100uF 20 10V GP TP 6 3x7 5 1 C003 P23 2401 000466 C AL 10uF 20 35V GP TP 5x7 5 1 C011 P24 2401 000914 C AL 22uF 20 16V GP TP 5x11 5 2 C005 C008 P25 2401 002075 C AL 4 7uF 20 50V...

Page 22: ...9 Schematic Diagrams 9 1 Schematic Diagrams 9 1 Samsung Electronics ...

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