Samsung MW7592W, MS5796W, MS7796W Service Manual

MICROWAVE OVEN

MS5796W / MS7796W

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

SEA

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 AVOID POSSIBLE EXPOSURE TO EXCESSIVE
MICROWAVE ENERGY

1. Precaution

1-1 Safety precautions ( )

Samsung Electronics 1-1

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.

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.

CENTRAL SERVICE CENTER

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, 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 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.

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 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 (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 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

PRECAUTION

Servicemen should remove their watches whenever
working close to or replacing the magnetron.

PRECAUTION

There exists HIGH VOLTAGE ELECTRICITY with high
current capabilities in the circuits of the HIGH VOLTAGE
TRANSFORMER secondary and filament terminals. It is
extremely dangerous to work on or near these circuits
with the oven energized.
DO NOT measure the voltage in the high voltage circuit
including filament voltage of magnetron.

PRECAUTION

Never touch any circuit wiring with your hand nor with
uninsulated tool during operation.

H. V. Diode

Short

H. V. Capacitor

Touch chassis ground first then short to the high
voltage capacitor terminal by using screwdriver or
jumper wire.

2. Specifications

2-1 Table of Specifications

Samsung Electronics 2-1

MODEL MS5796W / MS7796W

ITEM

TIMER 99 MINUTES 99 SECONDS

POWER SOURCE 120V/60HZ, AC

POWER CONSUMPTION MICROWAVE : 1,450W

OUTPUT POWER 1100 Watts

(IEC-705 TEST PROCEDURE)

OPERATING FREQUENCY 2,450MHz

MAGNETRON OM75PH(31)ESS

COOLING METHOD COOLING FAN MOTOR

OUTSIDE DIMENSIONS 20

11/32

(W) x 11

11/16

(H) x 14

29/32

(D) ( 21

7/8

(W) x 12

5/16

(H) x 16

21/32

(D))

NET WEIGHT 35.3 lbs. ( 38.6 lbs. )

SHIPPING WEIGHT 38.6 lbs ( 43 lbs. )

( ) : MS7796W

3-1 Samsung Electronics

One Minute +

Press once for every minute of
cooking at High power.

Sensor Cook Buttons

Sensor settings to cook popular foods.

Auto Defrost

Sets weight of food be defrosted.

Sensor Reheat

Gentle Cook

Press to set gentler cooking with reduced power.

Gentle Cook

Press to see help information about the

feature you are using.

Number Buttons

Sets cooking times or amounts and power
levels other than high..

More / Less Button

Increases or decreases cooking time.

Power Level

Sets power to level other than high.

Clock

Sets current time.

Start

Press to start cooking.

Pause / Canel

Press to pause oven or correct a mistake.

Kitchen Timer

Sound Button

1

2

3

6

4

5

8

7

0

9

Clock

Kitchen Timer

Auto
Defrost

Sensor
Reheat

Pause/Cancel

Start

More / Less

Sensor Cook

Fish

Popcorn

Potato

Fresh
Vegetable

Frozen
Dinner

Frozen
Breakfast

Baby
Food

Diet
Cook

Help

Screen

One

Minute +

Gentle

Cook

Power Level

Sound

3. Operating Instructions

3-1 Control Panel

3-2 Features & External Views

Door

Ventilation Holes

Light

Safety Interlock Holes

Control Panel

Open Door Push Button

Guide Roller

Glass Tray

Door Latches

517 / (556) mm

370 / (410) mm

( ) : MS7796W

297 / (313) mm

215 / (270) mm

379 / (448) mm

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 the air cover.

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

4. Take out the magnetron very carefully.

5. Remove tow screws from the back panel of fan
motor assembly.

6. Take out the fan motor assembly.

7. Remove the oven lamp by pulling 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.

4-2 Replacement of High Voltage Transformer

Lamp

Cover Air

Magnetron

H. V. Trans

H. V. Capacitor

Thermo S/W

Fan Motor

Screw

4-3 Replacement of Door Assembly

4-2 Samsung Electronics

4-3-3 Removal of Key Door & Spring

Remove pin hinge from Door "E"

Detach spring from Door "E" and key door.

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.

Insert flat screwdriver into the gap between Door
"A" and Door "C" to remove Door "C". Be careful
when handling Door "C" because it is fragile.
Then remove the door assembly.

4-3-1 Removal of Door "C"

4-3-2 Removal of Door "E"

Disassembly and Reassembly

Door "C"

Door "A"

Door "E"

Key Door Spring

Door "E"