SAMSUNG M757SDW Service Manual

MICROWAVE OVEN

M757

SERVICE

Manual

MICROWAVE OVEN CONTENTS

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M757

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

SEI

ELECTRONICS

Printed in Korea DE68-62321A

Samsung Electronics

(a) Do not operate or allow the oven to be

operated with the door open.

(b) Make the following safety checks on

all ovens to be serviced before activating the magnetron or other microwave source, and make repairs as necessary: (1) Interlock operation, (2) proper door closing, (3) seal and sealing surfaces (arcing,

wear, and other damage),

(4) damage to or loosening of hinges

and latches,

(5) evidence of dropping or abuse.

(c) Before turning on microwave power

for any service test 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 released to the owner.

(e) A Microwave leakage check to verify

compliance with the Federal performance standard should be performed on each oven prior to release to the owner.

PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO A VOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY

1. Precaution

1-1 Safety precautions ( )

Samsung Electronics 1-1

1. All repairs should be done in accordance with the procedures described in this manual. This product complies with Federal Performance Standard 21 CFR Subchapter J (DHHS).

2. Microwave emission check should be performed to prior to servicing if the oven is operative.

3. If the oven operates with the door open : Instruct the user not to operate the oven and contact the manufacturer and the center for devices and radiological health immediatly.

4. Notify the Central Service Center if the microwave leakage exceeds 5 mW/cm

2

5. Check all grounds.

6. Do not power the MWO from a "2-prong" AC cord. Be sure that all of the built-in protective devices are replaced. Restore any missing protective shields.

7. When reinstalling the chassis and its assemblies, be sure to restore all protective devices, including: nonmetallic control knobs and compartment covers.

8. Make sure that there are no cabinet openings through which people--particularly children--might insert objects and contact dangerous voltages. Examples: Lamp hole, ventilation slots.

9. Inform the manufacturer of any oven found to have emmission in excess of 5 mW/cm2, Make repairs to bring the unit into compliance at no cost to owner and try to determine cause. Instruct owner not to use oven until it has been brought into compliance.

SAMSUNG ELECTRONICS ITALY S.P.A VIA F.LLI GRACCHI,48 20092-CINISELLO BALSAMO MILAN ***ITALY

10. Service technicians should remove their watches while repairing an MWO.

11. To avoid any possible radiation hazard, replace parts in accordance with the wiring diagram. Also, use only the exact replacements for the following parts: Primary and secondary interlock 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 Warning: Use exact replacement parts only, i.e., only those that are specified in the drawings and parts lists of this manual. This is especially important for the Interlock switches, described above. Never alter or add to the mechanical or electrical design of the MWO. Any design changes or additions will void the manufacturer's warranty.10.Always unplug the unit's AC power cord from the AC power source before attempting to remove or reinstall any component or assembly.

14. Never defeat any of the B+ voltage interlocks. Do not apply AC power to the unit (or any of its assemblies) unless all solid-state heat sinks are correctly installed.

15. 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.

16. Always connect a test instrument's ground lead to the instrument chassis ground before connecting the positive lead; always remove the instrument's ground lead last.

Follow these special safety precautions. Although the microwave oven is completely safe during ordinary use, repair work can be extremely hazardous due to possible exposure to microwave radiation, as well as potentially lethal high voltages and currents.

17. When checking the continuity of the witches or transformer, always make sure that the power is OFF, and one of the lead wires is disconnected.

18. Components that are critical for safety are indicated in the circuit diagram by shading, or .

19. Use replacement components that have the same ratings, especially for flame resistance and dielectric strength specifications. A replacement part that does not have the same safety characteristics as the original might create shock, fire or other hazards.

1. High Voltage Warning Do not attempt to 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 (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 screwdriver.)

3. High voltage is maintained within specified limits by close-tolerance, safety-related components and adjustments. If the high voltage exceeds the specified limits, check each of the special components.

1-2

Pretaution

Samsung Electronics

1-2 Special Servicing Precautions (Continued)

1-3 Special High Voltage Precautions

Fig. 1-1. Discharging the High Voltage Capacitor

2. Specifications

2-1 Table of Specifications

Samsung Electronics 2-1

TIMER 99 MINUTES 90 SECONDS POWER SOURCE 230V 50Hz, AC POWER CONSUMPTION MICROWAVE : 1,300W OUTPUT POWER FROM 80 TO 800W (10 LEVEL POWER)

(IEC-705 TEST PROCEDURE) OPERATING FREQUENCY 2,450MHz MAGNETRON OM75SH(31) COOLING METHOD COOLING FAN MOTOR OUTSIDE DIMENSIONS 489(W) x 275(H) x 371(D)

POWER LEVEL

% M757

10% 80W 4 sec 26 sec 20% 160W 7 sec 23 sec 30% 240W 10 sec 20 sec 40% 320W 13 sec 17 sec 50% 400W 16 sec 14 sec 60% 480W 19 sec 11 sec 70% 560W 22 sec 8 sec 80% 640W 25 sec 5 sec 90% 720W 28 sec 2 sec

100% 800W 30 sec 0 sec

ON TIME OFF TIME

2-2 Comparison Chart

MODEL

FEATURE

MORE/LESS -

AUTO COOK/DISH O AUTO DEFROST O TIME COOK O POWER LEVEL O INSTANT COOK O MEMORY O BOOST O CHILD LOCK CLOCK O GRILL COMBI -

M757

Auto Deforst Button

Power Level

Selection Button

Stop/Cancel Button

Start Button

Dial Knob(Time,

Weight and Auto Cook Code

Selection Botton)

Deodorization Botton

Clock Setting Button

Memory Cook

Feature Button

Auto

Reheat&Cook Serving Size

Selection Button

Instant Cook Button

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3. Operating Instructions

3-1 Control Panel

Samsung Electronics 3-1

3-2 Features & External Views

,,,,,,,,,,,,,,,,,

Door

Ventilation Slot Light

Safety Interlock Holes

Control Panel

Open Door Push Button

Guide Roller

Glass Plate

Door Latches

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M757

489mm

357mm

275mm

200mm

371mm

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M757

4. Disassembly and Reassembly

4-1 Replacement of Magnetron, Motor Assembly and Lamp

Samsung Electronics 4-1

Remove the magnetron including the shield case, permanent magnet, choke coils and capacitors (all of which are contained in one assembly).

1. Disconnect all lead wires from the magnetron and lamp.

2. Remove a screw securing the magnetron supporter.

3. Remove the magnetron supporter.

4. Remove the air cover.

5. Remove screws securing the magnetron to the wave guide.

6. Take out the magnetron very carefully.

7. Remove screws from the back panel.

8. Take out the fan motor.

9. Remove the oven lamp by rotating to pull out from hole of air cover.

NOTE1: When removing the magnetron, 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.

4-1 Replacement of High Voltage Transformer

Lamp

Magnetron

H. V. Trans

H. V. Capacitor

Screw

Thermo S/WCover Air

Fan Motor

H. V. Trans

Screws

BKT-Mountain