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- 2 -

H. V. Diode

Short

H. V. Capacitor

1-2 Special Servicing Precautions (Continued)

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.

1-3 Special High Voltage Precautions

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 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.

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.

PRECAUTION

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

Fig. 1-1 Discharging High Voltage Capacitor

Touch chassis ground first then short to the high

voltage capacitor terminal by using screwdriver or

jumper wire.

Summary of Contents for M171FN

Page 1: ...ONTENTS MICROWAVE OVEN 1 Precaution 2 Specifications 3 Operating Instructions 4 Disassembly and Reassembly 5 Alignment and Adjustments 6 Troubleshooting 7 Exploded Views and Parts List 8 Schematic Diagrams Manual M171FN WHITE ...

Page 2: ...s 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 s...

Page 3: ...hould 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...

Page 4: ...igure 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 PRECAUTIO...

Page 5: ...FREQUENCY COOLING METHOD MAGNETRON OUTSIDE DIMENSIONS mm OVEN DIMENSIONS mm SHIPPING DIMENSIONS mm SHIPPING WEIGHT APPROX 35 MINUTES 230V 50Hz SINGLE PHASE 1 150W 100W 800W ICE 705 2 450MHz COOLING FAN MOTOR OM75S 31 ESS 489 W x 275 H x 397 D 306 W x 211 H x 320 D 557 W x 329 H x 466 D NET 13 5kg GROSS 15 0kg ...

Page 6: ...xternal Views DEFROST TIMER KNOB INSTANT REHEAT VARIABLE COOKING POWER CONTROL KNOB DOOR TURNTATBLE COUPLER ROLLER RING SAFETY INTERLOCK HOLES LIGHT VARIABLE COOKING POWER CONTROL KNOB VENTILATION HOLS TIMER KNOB DOOR LATCHES HANDLE 275mm 489mm 342mm 397mm 206mm ...

Page 7: ... 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 4 2 Replacement of High Voltage Transformer 1 Discharge the high voltage capacitor 2 Disconnect all the leads 3 Remove the mounting bolts 4 Reconnect the leads correctly and firmly PRECAUTION Serviceme...

Page 8: ...fragile Then remove the door assembly 4 3 2 Removal of Door E 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 4 3 3 Removal of Key Door Spring Remove pin hinge from Door E Detach spring from Door E and key door Door E Door A Door C 90 ...

Page 9: ...operate properly check if any other part such as the control circuit board blower motor or high voltage transformer is defective 4 5 Replacement of Drive Motor 1 Take out the glass tray guide roller and coupler from cavity 2 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 secur...

Page 10: ...4 6 1 Removal of Control Box Assembly 1 Disconnect the connectors from the control box assembly 2 Remove screws securing the control box assembly 3 Remove the knobs of the control box A ssy 4 Remove the screw securing the timer CONTROL BOX SCREW ...

Page 11: ...it 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 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...

Page 12: ...y 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 l...

Page 13: ...edure 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 91 times the of centigrade temperature 5 7 Microwave Heat Distribution Heat Evenness The microwave heat distribution can be checked indirectly by measuring the water temperature ri...

Page 14: ...en 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 near the opening of magnetron the surface of the air guide and the surface of the wave guide as shown in the following photo but avoid the high voltage components The reading should be less than 4mW cm2 5 10 Note on Measurement 1 Do not exceed the limited sca...

Page 15: ...ns secondary open the transformer may be faulty Replace H V Transformer Oven lamp does not light 1 Fuse blown out Check fuse Replace the fuse 2 Poor contact of power cord Check continuity of power supply cord Also check whether the power cord is securely wired Adjust or replace the power supply cord 3 Defective lamp The fan motor rotates but lamp does not light Replace the lamp 4 Defective timer c...

Page 16: ...well to the door hinge Fasten or tighten Timer does not operate 1 Defective timer motor If the timer does not operate with 21V applied to the terminals the timer motor amy be faulty Replace timer 2 Defective contacts of timer S W The lamp does not light Replace timer Cooking tray does not rotate 1 Defective drive motor Check to see if 21V exists at the motor terminals If so motor will be defective...

Page 17: ... and OFF repeatedly Replace or adjust 6 Open coil of H V Trans former Check the continuity of primary coil and secondary coil If there is no continuity H V Transformer is defective Replace the H V Transformer 7 Shorted H V capacitor Check the continuity of capacitor If the capacitor shorts the fuse blows Replace the H V Capacitor 8 Monitor fuse blown out Check the monitor fuse on the noise filter ...

Page 18: ...d Views M001 M015 M017 M014 M019 M022 M020 M023 M157 M049 M029 M051 T001 T017 M034 M038 M039 M040 M043 M048 M132 W002 M042 M035 M037 M036 B018 B006 B001 B002 B011 B010 MM127 C032 C082 C005 C092 C024 D004 D006 D005 D019 D003 D002 D011 D049 D007 D015 ...

Page 19: ...23 DE31 10184A MOTOR FAN SMF 3RDEA 230V50Hz 2400rpm 3rd 1 M029 DE47 20008A THERMOSTAT PW2N 52JC 100 60 250V 7 5A H 1 M034 DE67 00140A COUPLER NC2000 0 6 0 8 PPS ESS840 3G 1 M035 OM75S 31 ERH ASSY MAGNETRON OM75S 31 ERH 1 M036 4713 001046 LAMP INCANDESCENT 240V 104mA 25W ORG 1 M037 DE71 60457B COVER AIR 3RD 0 7 BTM PP 1 M038 DE26 00079A TRANS H V SHV EURO1 230V 50HZ 2130V 3 6V 1 M039 2501 001016 C ...

Page 20: ...WHT 2 D002 DE64 00644B DOOR A M171FN G271FN ABS PURE WHT W9501 1 D003 DE64 00646B SCREEN DOOR M171FN G271FN SAN SMOG 1 D004 DE92 50133C ASSY DOOR E MW4593G BLK 3RD 0 7 1 D005 DE01 00112A FILM DOOR PET L268 T0 15 W150 NTR 1 D006 DE64 40008B DOOR C PP CE745G BLK 1 D007 DE61 00198A SPRING KEY M1877 HSWR PI0 7 D6 23 1 4 1 D011 DE64 00264A KEY DOOR 3RD W NEW POM BLK 1 D015 DE94 00124B ASSY DOOR SUB MW4...

Page 21: ... 2S 4X12 TOOTHED 1 AIR COVER DE60 10082H SCREW A 2S 4X12 TOOTHED 2 B LATCH DE60 10082H SCREW A 2S 4X12 TOOTHED 3 B PLATE DE60 10082H SCREW A 2S 4X12 TOOTHED 1 C BLOWER DE60 10082H SCREW A 2S 4X12 TOOTHED 1 C BOX DE60 10082H SCREW A 2S 4X12 TOOTHED 4 O PANEL DE60 10098A SCREW ASSY TAP TITE GLD SWRCH18A ZPC2 PH TC M4X8 WT 1 D MOTOR DE60 30016A NUT FLANGE M4 MSWR10 2 F MOTOR DE60 10069A SCREW TAP TH ...

Page 22: ... This Document can not be used without Samsung s authorization RED RED BRN BLU FA F HIGH VOLTAGE TRANSFORMER H V FUSE HIGH VOLTAGE CAPACITOR HIGH VOLTAGE DIODE TO CHASSIS MAGNETRON SYMBOL COLOR BRN BROWN BLK BLACK RED RED BLU BLUE ORG ORANGE RED RED ...

Page 23: ...ectronics Co Ltd May 2003 Printed in Korea Code No DE68 03150A This Service Manual is a property of Samsung Electronics Co Ltd Any unauthorized use of Manual can be punished under applicable International and or domestic law ...

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