SAMSUNG CE959GTDAMF Service Manual

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

1 min +

1. 2. 3.

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1. 2. 3.

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.

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 TOA VOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWA VE 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

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 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.

17. When checking the continuity of the switches 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 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

CE959G

Auto

1 min +

Auto

1. 2. 3.

Auto Reheat Programs Auto Cook Programs Power Level Button

Auto Defrost Programs

Cancel Button

More/Less Button

Combi Button

Grill Button

Clock Setting Button Start Button

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

Handle Door

Glass Plate

Heater

Door Latches

AUTO

CE959G

1 min +

AUTO

1. 2. 3.

517mm

369mm

297mm

216.4mm

410mm

1 min +

1. 2. 3.

Auto

1. 2. 3.

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 bracket mounting.

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.Remove the assy noise filter.

9. Take out the fan motor.

10. Remove the oven lamp by pulling out from hole of air cover carefully.

. 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

MAGNETRON

BRACKET T.C.O

MGT T.C.O

MOTOR FAN

Cover Air Screw

MGT Screws

Fan Screws

COVER AIR

LAMP

H.V.Fuse

H.V.Diode

H.V.Capacitor

H.V.C Bracket

H.V.Trans

Bracket HVC Scrw

H.V.Trans Scrws

4-3 Replacement of Door Assembly

4-2 Samsung Electronics

Disassembly and Reassembly

4-3-1 Removal of Door Assembly

Remove screws securing the upper hinge and lower hinge. Then remove the door assembly.

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.

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.

1. Insertion depth of the thin metal plate should be

0.5mm or less.

4-3-4 Removal of Key Door & Spring

Remove pin hinge from Door "E"

Detach spring from Door "E" and key door.

4-3-2 Removal of Door "C"

4-3-3 Removal of Door "E"

Upper Hinge

Lower Hinge

Screw

Door "C"

Door "A"

Door "E"

Key Door Spring

Door "E"

Samsung Electronics 4-3

1. Disconnect the oven from the power source.

2. Remove the 10A fuse in the Noise filter.

3. When replacing the 10A fuse, be sure to use an exact replacement part. If new 10A fuse blows out again after replacement, check the primary interlock switch, door sensing switch and interlock monitor switch.

4. 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.

1. Take out the glass tray and guide roller from the cavity.

Turn the oven upside down to replace the drive motor.

3. Remove a screw securing the drive motor cover.

4. Disconnect all the lead wires from the drive motor.

5. Remove screws securing the drive motor to the cavity.

6. Remove the drive motor and coupler.

7. When replacing the drive motor, be sure to remount it in the correct position with the coupler.

8. Connect all the leads to the drive motor.

9. Screw the drive motor cover to the base plate with a screw driver.

4-4 Replacement of Fuse

4-5 Replacement of Drive Motor

Disassembly and Reassembly

Screw

Drive Motor Cover Base Plate

Thermo Switch

Drive Motor

4-3-5 Reassembly Test

After replacement of the defective component parts of the door, reassemble it and follow the instructions below for proper

installation and adjustment so as to prevent an excessive microwave leakage.

1. When mounting the door to the oven, be sure to adjust the door parallel to the bottom line of the oven face plate by moving the upper hinge and lower hinge in the direction necessary for proper alignment.

2. Adjust so that the door has no play between the inner door surface and oven front surface. If the door assembly is not mounted properly, microwave energy may leak from the space between the door and oven.

3. Do the microwave leakage test.

4-6 Replacement of Control Circuit Board

4-6-1 Removal of Control Box Assembly

4-4 Samsung Electronics

1. Be sure to ground any static electric charge in your body and never touch the control circuit.

2. Disconnect the connectors from the control circuit board.

3. Remove screws securing the control box assembly.

1. Remove screws securing the control circuit board.

2. Lift up the control circuit board from the Ass'y control box.

4-6-2 Removal of P.C.B Assembly

Sub P.C.B Scrws

Sub P.C.B

Main P.C.B

Main P.C.B Scrws

Disassembly and Reassembly

Samsung Electronics

5. Alignment and Adjustments

5-1 High Voltage Transformer

5-2 Low Voltage Transformer

5-3 Magnetron

5-1

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.

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.

Secondary 90.0Ω ± 10%

Filament Shows Continuity Primary 1.45Ω ± 10%

Terminals Resistance

1~2(Input) 1280Ω 4~5(Output17V) 18.9Ω 7~8(Output2.9V) 3.7Ω

Filament Terminals

Primary

Terminals

Secondary

Terminals

Magnetron Antenna

Gasket Plate

Cooling Fins

Samsung Electronics

5-4 High Voltage Capacitor

5-5 High Voltage Diode

5-6 Main Relay and Power Control Relay

5-7 Adjustment of Primary Switch, Door Sensing Switch and Monitor Switch

5-2

1. Check continuity of the capacitor with the meter set at the highest resistance scale.

2. Once the capacitor is charged, a normal capacitor shows continuity for a short time, and then indicates 9MΩ.

3. A shorted capacitor will show continuous continuity.

4. An open capacitor will show constant 9MΩ.

5. Resistance between each terminal and chassis should read infinite.

1. Isolate the diode from the circuit by disconnecting its leads.

2. With the ohm-meter set at the highest resistance scale, measure across the diode terminals. Reverse the meter leads and read the resistance. A meter with 6V, 9V or higher voltage batteries should be used to check the front-to back resistance of the diode (otherwise an infinite resistance may be read in both

directions). The resistance of a normal diode will be infinite in one direction and several hundred KΩ in

the other direction.

1. When mounting Primary switch and Interlock Monitor switch to Latch Body, consult the figure.

2. No specific adjustment during installation of Primary switch and Monitor switch to the latch body is necessary.

3. When mounting the Latch Body to the 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 switches again by following the components test procedures.

5. Confirm that the gap between the switch housing and the switch actuator is no more than

0.5mm when door is closed.

1. The relays are located on the PCB Ass'y. Isolate them from the main circuit by disconnecting the leads.

2. Operate the microwave oven with a water load in the oven. Set the power level set to high.

3. Check continuity between terminals of the relays after the start pad is pressed.

Precaution

For continued protection against radiation hazard, replace parts in accordance with the wiring diagram and be sure to use the correct part number for the following switches: Primary and door sensing switches, and the interlock monitor switch (replace all together). Then follow the adjustment procedures below. After repair and adjustment, be sure to check the continuity of all interlock switches and the interlock monitor switch.

Alignment and Adjustments

Door Open Door Closed

Primary switch ∞ 0 Monitor switch (COM-NC) 0 ∞

Door Sensing S/W

∞

Primary Interlock Switch

Lever Door(B)

Body Latch

Door Sensing

Switch

Interlock Monitor Switch

Samsung Electronics 5-3

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 should be made if temperature rise is marginal. NOTE 2: Output power in watts is computed by multiplying the temperature rise (step 5) by a factor of 90 times the of centigrade temperature.

4.187 x 1000 x ∆T+0.88xMcx(T2-T0)

Output Power =

46.5

46.5: Heating Time (sec)

4.187 : Coefficient for Water 1000 : Water (cc)

∆T : Temperature Rise (T2-T1)

Mc : Cylindrical borosilicate glass weight To : Room temperature.

5-8 Output Power of Magnetron

Alignment and Adjustments

CAUTION

MICROWAVE RADIATION

PERSONNEL SHOULD NOT ALLOW EXPOSURE TO MICROWAVE RADIATION FROM MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY.

The output power of the magnetron can be measured by performing a water temperature rise test. Equipment needed : * Two 1-liter cylindrical borosilicate glass vessel (Outside diameter 190 mm) * One glass thermometer with mercury column NOTE: Check line voltage under load. Low voltage will lower the magnetron output. Make all temperature and time tests with accurate equipment.

1. Fill the one liter glass vessel with water.

2. Stir water in glass vessel with thermometer, and record glass vessel's temperature ("T1", 10±1ûC).

3. After moving the water into another glass vessel, place it in the center of the cooking tray. Set the oven to high power and operate for 48seconds exactly. (1.5 seconds included as a holding time of magnetron oscillation:)

4. When heating 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. (∆T)

6. The output power is obtained by the following formula;

The microwave heat distribution can be checked indirectly by measuring the water temperature rise at certain positions in the oven:

1. Prepare five beakers made of 'Pyrex', having 100 milliliters capacity each.

2. Measure exactly 100milliliters off water load with a measuring cylinder, and pour into each beaker.

3. Measure the temperature of each water load. (Readings shall be taken to the first place of decimals.)

4. Put each beaker in place on the cooking tray as illustrated in figure below. Start heating.

5. After heating for 2 minutes, measure the water temperature in each beaker.

6. Microwave heat distribution rate can be calculated as follows:

Minimum

Temperature Rise

Heat Distribution = X 100(%)

Maximum

Temperature Rise

The result should exceed 65%.

5-9 Microwave Heat Distribution - Heat Evenness

D/4

Cooking Tray

Beaker

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