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5-1

Samsung Electronics

5. Alignment and Adjustments

5-1 High Voltage Transformer

5-2 Low Voltage Transformer

5-3 Magnetron

1. Remove connectors from the transformer terminals

and check continuity. 

2. Normal resistance readings are as follows:

(Room temperature = 20ûC)

1. Continuity checks can indicate only an open

filament or a shorted magnetron. To diagnose an
open filament or shorted magnetron :

2. Isolate the magnetron from the circuit by

disconnecting its leads.

3. A continuity check across the magnetron filament

terminals should indicate one ohm or less.

4. A continuity check between each filament 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. 160

W

Filament

Approx.0.08

W

Primary

Approx.2.9

W

Terminals

Resistance

1~2(Input)

1,300

W

3~4(Output 2.9V)

3.947

W

5~6(Output13V)

2.117

W

Cooling Fins

Gasket Plate

Magnetron Antenna

PRECAUTION

1. High voltage is present at the high voltage terminals during any cook cycle.
2. It is neither necessary nor advisable to attempt measurement of the high voltage.
3. Before touching any oven components or wiring, always unplug the oven from its power source and

discharge the high voltage capacitor.

Summary of Contents for M308R

Page 1: ...W SERVICE Manual 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: ... or inspection within the microwave generating compartments check the magnetron wave guide or transmission line and cavity for proper alignment integrity and connections d Any defective or misadjusted components in the interlock monitor door seal and microwave generation and transmission systems shall be repaired replaced or adjusted by procedures described in this manual before the oven is releas...

Page 3: ...tor switch 12 If the fuse is blown by the Interlock Monitor Switch Replace all of the following at the same time Primary door sensing switch and power relay 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 Warning Use exac...

Page 4: ...o measureany 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 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 ...

Page 5: ...lectronics 2 1 TIMER 15 MINUTES POWER SOURCE 230V 50Hz AC POWER CONSUMPTION MICROWAVE 800W OUTPUT POWER 500W IEC 705 TEST PROCEDURE OPERATING FREQUENCY 2 450MHz MAGNETRON OM52S 20 COOLING METHOD COOLING FAN MOTOR OUTSIDE DIMENSIONS 281 W x 330 5 H x 316 D ...

Page 6: ...onvenience Features Drinks Snacks Meals Time Feature Stop Button 5 s 1 min h min 3 Operating Instructions 3 1 Control Panel 3 2 Features External Views Door latches Door Control Panel Display Glass Cook Tray 281mm 330 5mm 316mm ...

Page 7: ...rts 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 Transformer PRECAUTION Servicemen should remov their watches ...

Page 8: ...erlock switch door sensing switch monitor switch and power relay 3 When the above three switches operate properly check if any other part such as the control circuit board blower motor or high voltage transformer is defective 4 4 Replacement of Fuse After replacement of the defective component parts of the door reassemble it and follow the instructions below for proper installation and adjustment ...

Page 9: ...ly 4 Remove the screw securing the ground 1 Window display should not be disassembled as its mounting tabs will be broken If repair work is difficult replace with Ass y control panel 2 The membrane key board is attached to the escutcheon base with doublefaced adhesive tape Therefore applying hot air such as using of hair dryer is recommended for smoother removal 1 Remove screws securing the contro...

Page 10: ...t 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 160W Filament Approx 0 08W Primary Approx 2 9W Terminals Resistance 1 2 Input 1 300W ...

Page 11: ...e oven assembly adjust 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 sw...

Page 12: ...tor of 50 times the of centigrade temperature 4 187 x 1000 x DT Output Power 83 83 Heating Time sec 4 187 Coefficient for Water 1000 Water cc DT Temperature Rise T2 T1 5 8 Output Power of Magnetron CAUTION MICROWAVE RADIATION PERSONNEL SHOULD NOT ALLOW EXPOSURE TO MICROWAVE RADIATION FROM MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY 5 3 Alignment and Adjustments 5 9 Procedure for...

Page 13: ...ur 275 15cc of 20 5ûC 68 9ûF water in a beaker which is graduated to 600cc and place the beaker in the center of the oven 3 Start the oven at the highest power level 4 Set survey meter dual ranges to 2 450MHz 5 Using the survey meter and spacer cone as described above measure arnear the opening of magnetron the surface of the air guide and the surface of the wave guide as shown in the following ph...

Page 14: ...tive 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 Refer to opera...

Page 15: ...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 Oven stops operation during cooking 1 Open or loose wiring of primary Adjust door and latch switches interlock switch 2 Operation of thermal cutout Cavity Sparks 1 Metallic war...

Page 16: ...Samsung Electronics 7 Exploded Views and Parts List 7 1 Exploded Views 1 33 31 34 35 36 30 28 27 26 29 23 22 25 24 20 21 17 16 18 19 15 14 12 13 11 40 41 10 8 9 2 5 4 3 6 7 32 37 38 42 39 7 1 ...

Page 17: ... 400 ORG 1 YELLOW 13 DE66 20283B BUTTON SELECT B ABS HR0370D MELON YEL 88099 1 MELON 13 DE66 20283F BUTTON SELECT B ABS G3328 SILK D GRY M308 D AMF 1 GRAY 13 DE66 20283H BUTTON SELECT B ABS EURO YEL M308R Y BWT 1 YELLOW 14 DE72 70213L CONTROL PANEL ABS M308R A BWT MELON GRN 88099 1 MELON 14 DE72 70213K CONTROL PANEL ABS M308R D BWT D GRY G3328 1 GRAY 14 DE72 70213P CONTROL PANEL ABS HR0370D M308R ...

Page 18: ...15A NUT FLANGE M5 P0 8 MSWR10 FEFZY 4 MGT DE60 10088A SCREW TAP PH PH M3 L8 FEFZY PLAIN 4 PCB MAIN DE60 10088A SCREW TAP PH PH M3 L8 FEFZY PLAIN 3 PCB SUB 7 3 Standard Parts List 7 2 Main Parts List Ref No Parts No Description Specification Q ty Remarks 36 DE39 20145A ASSY POWER CORD MOONSUNG 230V50Hz M308 1 37 DE47 20173A THERMOSTAT PW 2N 90 60 30 187Y 250V7 5A 9 1 38 DE93 20096B ASSY BODY LATCH ...

Page 19: ...Samsung Electronics 8 1 8 P C B Diagrams 8 1 P C B Diagram ...

Page 20: ... R011 P18 2001 000429 R CARBON 1KOHM 5 1 8W AA TP 1 8X3 2MM 1 R001 R002 R003 R008 R009 R019 P19 2001 000435 R CARBON 1MOHM 5 1 8W AA TP 1 8X3 2MM 1 R021 P20 2001 000502 R CARBON 20OHM 5 1 4W AA TP 2 4X6 4MM 1 R012 R013 R014 R015 R016 P20 2001 000502 R CARBON 20OHM 5 1 4W AA TP 2 4X6 4MM 1 R017 R018 P21 2001 000780 R CARBON 470OHM 5 1 8W AA TP 1 8X3 2MM 1 R007 P22 2001 000904 R CARBON 620OHM 5 1 8W...

Page 21: ...SSY NOISE FILTER H V DIODE H V CAPACITOR H V FUSE FAN MOTOR PRIMARY S W POWER RELAY MAIN FUSE MONITOR FUSE THERMAL S W P C B PATTEN C2 C1 RESISTOR 230V 50Hz L V T MONITOR S W LIN CAPACITOR BLU BLU BLK BRN ORG RED BRN BRN R1 L V TRANS KEY BOARD ASSY MAIN P C B DOOR SENSING S W G YEL BLU BLU WHT FM ...

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