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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/cm

2

,

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.

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.

Summary of Contents for G643CR

Page 1: ...in G643C 1 min Auto lbs oz g kg lbs kg oz g h 10min min 1min Auto Auto 10s M M643CR 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 BWT ...

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: ...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 4: ...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 5: ...METHOD COOLING FAN MOTOR OUTSIDE DIMENSIONS 489 W x 275 H x 365 D POWER LEVEL 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 O AUTO COOK DISH O AUTO DEFROST O TIME COOK O ...

Page 6: ...on Power Level Selection Button Memory Button Stop Button 3 Operating Instructions 3 1 Control Panel Samsung Electronics 3 1 3 2 Features External Views Door VentilationSlot Heater Light SafetyInterlockHoles ControlPanel OpenDoorPushButton GuideRoller MetalRack GlassPlate DoorLatches G645C lbs kg oz g h 10min min 1min Auto Auto 10s 1min M 489mm 356 5mm 275mm 203mm 365mm G645C lbs kg oz g h 10min m...

Page 7: ...agnetron 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 g...

Page 8: ...andling 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 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 Key Door Spring Door E Disassembly and Reas...

Page 9: ...a screw driver 10 Remount the coupler in the correct position 1 Take out the outer panel 2 Disconnect the connectors from the heater ceramic and wire leade 3 Remove screws securing the bracket upper to the oven cavity 4 Remove one screw securing the bracket heater 4 4 Replacement of Fuse 4 5 Replacement of Drive Motor 4 6 Replacement of Ceramic Heater Disassembly and Reassembly Screw Drive Motor C...

Page 10: ...onnecting the FPC connector make sure that the holes on the connector are properly engaged with the hooks on the Plastic Fastener 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 usi...

Page 11: ...inal 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 ...

Page 12: ...djust 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 f...

Page 13: ...nal power test should be made if temperature rise is marginal NOTE 2 Output power in watts is computed by multiplying the temperature rise step E by a factor of 91 times the of centigrade temperature 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 ...

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: ...ise 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 21V Oven stops operation during cooking 1 Open or loose wiring of primary Adjust door and latch s...

Page 16: ...s List 7 1 Exploded Views 7 1 M1 M2 M34 M7 M13 M5 M4 M14 M35 M36 M19 M3 M28 M18 M20 M11 M16 M17 M22 M21 M25 M26 M23 M12 M15 M24 M27 M32 M9 M10 B5 B4 B3 B2 B1 M37 D4 D5 D3 D2 D1 D7 D8 D6 M6 M30 M33 M29 M31 M32 C1 C2 C3 C4 C5 C6 ...

Page 17: ...028 00 M 18 DE39 20054D ASSY POWER CORD KKP 4819D B206 250V6A L1500 1 79243 0072 04 M 19 DE47 70030D HEATER CERAMIC 115V 490W 260HM 6 1 M 20 DE61 50401A BRACKET HEATER ALSTER T0 5 60 70 M67G45 1 M 21 DE91 40093A ASSY NOISE FILTER SN EI0D 250V 10A 1 M 22 DE31 30031A FAN MOTOR SMF745EA 230V 50HZ ASSY FAN MOTOR 1 M 23 DE91 70065A ASSY H V D BMP28 SEMA 12KV SUMI 1 79169 0153 00 M 24 DE91 70061B ASSY H...

Page 18: ...n Specification Q ty Remarks Old No C 1 DE91 10391A ASSY P C B MAIN 230V50HZ NS VFD CE645C CIS 1 C 2 DE66 20171A BUTTON PUSH ABS WHT G643C 1 C 3 DE61 70076A SPRING BUTTON HSWR PI0 6 1 76674 239 310 C 4 DE34 10212A SWITCH MEMBRANE PET 230V50HZ 89 4 156 4 G6 1 C 5 DE67 40142A WINDOW DISPLAY ACRYL BLK G643C 1 C 6 DE72 70164A CONTROL PANEL ABS WHT T2 5 G643C 1 7 5 Body Latch Parts List Ref No Parts No...

Page 19: ...FZY 1 CV AIR 77128 540 101 DE60 10080A SCREW WASHER M5 L12 2S 4 HVT 77154 202 910 DE60 10080A SCREW WASHER M5 L12 2S 4 MGT 77154 202 910 DE60 10082I SCREW A 2S 4X12 FEFZY 4 B PLTE 77154 203 8201 DE60 10082I SCREW A 2S 4X12 FEFZY 2 BD LAT 77154 203 8201 DE60 10082I SCREW A 2S 4X12 FEFZY 2 CON PA 77154 203 8201 DE60 10082I SCREW A 2S 4X12 FEFZY 4 OUT PN 77154 203 8201 DE60 10082J SCREW TAPPING TH 2S...

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

Page 21: ...ON 3 9Kohm 5 1 8W AA TP 1 8x3 2m 7 11 13 20 23 42 2001 000776 R CARBON 470ohm 5 1 2W AA TP 3 3x9m 1 R01 2001 000786 R CARBON 47Kohm 5 1 8W AA TP 1 8x3 2m 12 R30 41 2011 001043 R NETWORK 47Kohm 5 1 8W A SIP 8P BK 1 AR01 2202 000780 R CERAMIC MLC AXIAL UPO50F104Z 100NF 80 20 6 C06 09 12 15 2401 000247 C AL 1SA1ANB107MAN 100UF 20 10V GP 6 3X11M 1 C04 2401 000353 C AL 1SA1HWB101M 100UF 20 50V GP 10X16...

Page 22: ... RELAY POWER RELAY INRUSH RELAY GRILL RELAY DOOR SENSING SWITCH RESISTOR MONITOR SWITCH POWER RELAY F FA MAGNETRON NO COM NO COM NO NO BLK BLK BLK ORG ORG BLK BLK BLK BLU BLK COM 0V LAMP 230V40W DRIVE MOTOR FAN MOTOR L V TRANS PRIMARY LATCH SWITCH DOOR SENSING LATCH SWITCH MONITOR SWITCH L FM H V T H V D H V C 0 95uF H V FUSE 0 75A 1mH BRN BROWN BLU BLUE ORG ORANGE RED RED WHT WHITE BLK BLACK YEL ...

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