Frigidaire MFM-6D Page 36 Service Manual Download

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(TROUBLE 2) Digital readout display does not show programming, even if the membrane keyboard

is programmed by touching proper pads.

MEMBRANE KEYBOARD CHECK PROCEDURE

1. Check the pad

Condition

Check

Cause

Result

Remedy

Display does not
show programming
at all,even if
keyboard is
touched

Check each pad for
continuity of the
membrane keyboard
for the following
keyboard check
procedure

Normal

Abnormal

Malfunction
of touch
control
circuity of
control box
sub-assembly

Replace
control
box sub-
assembly

Malfunction
of the memb-
rane keyboard

Replace the
membrane
keyboard

NOTE: Before following the particular steps listed above in the trouble shooting guide for the

membrane keyboard, failure, please check for the continuity of each wire-harness between
the membrane keyboard and control box assembly.

PCB Termination

PCB Connector

DEFROST

COOK

CLOCK

DEFROST

COOK

STOP/CLEAR

START

Defrost

(Low)

Or Alam On

Defront

(Low)

Cook

(Med)

Cook

(High)

Lock

Time

Cook

(Med)

Cook

(High)

Porozen
Reg Lag

Beremeo

Soup

Quick On

30 Seca

Frozem

Pizea

Time

Alarm

Am/Pm

Alarm

Stop

Start

Stop

Clear

Baked

Potato

Dinner

Plate

To Cook:
1. Selet Power Level
or Preset from above
2. Enter cooking Time
(excopt for pecects)
3. Press Stait

To Set Time/Alam:
1. Press Time or Alarm
2. Enter desirad time
3. Select AM or PM
4. Prem Time or Alam
5. To shut off alam
Press Alarm Stop

JI-811 F3A

Fig. 7

MFM-6D

MFM-7DTP

Summary of Contents for MFM-6D

Page 1: ...MICROWAVE OVEN SERVICE MANUAL DEFROST COOK CLOCK DEFROST COOK 1 2 3 4 5 6 7 8 9 0 STOP CLEAR START Model No MFM 6D MFM 7DTP ...

Page 2: ...n 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 inspect...

Page 3: ...U HAVE READ THIS SERVICE MANUAL 2 For Safety Service Procedures 1 If the oven is operative prior to servicing a microwave emission check should be performed prior to servicing the oven 2 If any certified oven unit is found to have excessive emission level 5mW cm2 the service person should a inform the manufacturer importer or assembler b repair the unit at no cost to the owner c attempt to ascerta...

Page 4: ...C 60Hz SINGLE PHASE WITH GROUNDING POWER CONSUMPTION 920W MICROWAVE OUTPUT POWER 600W IEC 705 FREQUENCY 2450 MHz OUTSIDE DIMENSIONS WxHxD 495x 289 x 382mm 19 5 x 11 4 x 15 0 in CAVITY DIMENSIONS WxHxD 320x 225 x 330mm 12 6 x 8 9 x 13 0 in NET WEIGHT APPROX 14Kg 30 9 lbs TIMER 59 min 99 sec 59 min 99 sec POWER SELECTIONS 2 LEVELS 2 LEVELS ...

Page 5: ...e door is opened 6 Door release button Pushing this button stops oven operation and opens the door 7 Glass cooking tray Made of special heat resistant glass The tray must always be in proper position before operating Do not cook food directly on the tray 8 Roller guide Supports the glass cooking tray 9 Door screen Allows viewing of food The screen is designed so that light can pass through but not...

Page 6: ...al within the oven cavity Prevents microwave leakage 3 Oven Cavity 4 Spatter shield Protects the microwave outlet from splashes of cooking foods 5 Safety interlock system Prevents the oven from operating while the door is opened 6 Door release button Pushing this button stops oven operation and opens the door 7 Glass cooking tray Made of special heat resistant glass The tray must always be in prop...

Page 7: ... Power supply cord is about 6ft long 1 Longer cord sets or extension cord are available and may be used if care is exercised in their use 2 If a long cord sets or extension cords is used 1 the marked electrical rating of the cord set or extension cord should be at least as great as the electrical rating of the appliance 2 the extension cord must be a grounding type 3 wire cord and 3 the longer cor...

Page 8: ...en door is opened during the oven operation all information is retained If the START pad is touched and the oven does not operate check the area between the door and door seal for obstructions and make sure the door is closed securely The oven will not start cooking until the door is completely closed or the program has been reset NOTE When the cooking time is up the time pointer reads 0 you can h...

Page 9: ...e enter the time CLOCK 2 Touch CLOCK pad once more This is a 24 hour clock system CLOCK 4 Touch CLOCK pad The display will stop blinking and the colon starts blinking If you selected 12 hour clock system this digital clock allows you to set from 1 00 to 12 59 If you selected 24 hour clock system this digital clock allows you to set from 0 00 to 23 59 CLOCK DEFROST COOK DEFROST COOK 3 Enter the cor...

Page 10: ...dicator starts blinking to show the oven is in the DEFROST mode The display counts down the time to show you how much defrosting time is left in the DEFROST mode The oven beeps during the defrosting cycle to signal that the food needs to be turned or rearranged When the defrosting time ends you will hear 3 beeps START 2 Touch number pads for the defrosting time you want The display will show the n...

Page 11: ...ator starts blinking to show the oven is cooking The display counts down the time to show how much cooking time is left When the cooking time ends you will hear 3 beeps START 2 Touch nunber pads for the cooking time The display will show the numbers you pressed in the order you touched 5 3 0 DEFROST COOK NOTE Your oven can be programmed for 59 minutes 99 seconds 59 99 ...

Page 12: ...h number pads for the defrosting time you want The display will show the numbers you pressed in the order you touched 2 7 1 0 DEFROST COOK NOTE Your oven can be programmed for 59 minutes 99 seconds 59 99 3 Touch COOK pad The COOK indicator lights and 0 is displayed DEFROST COOK 4 Touch number pads for the cooking time The display will show the numbers you pressed in the order you touched 5 3 0 DEF...

Page 13: ...ven will beep and start COOK mode The DEFROST indicator goes off and the COOK indicator starts blinking The display counts down the time remaining in the COOK mode When the cooking time ends you will hear 3 beeps START 1 Press STOP CLEAR pad You can restart the oven by touching START pad Touch STOP CLEAR once more to erase all instructions You must enter in new instructions 2 Open the door You can...

Page 14: ...day by touching the numbers in sequence 4 Touch TIME pad The colon starts blinking If you selected 12 hour clock system this digital clock allows you to set from 1 00 to 12 59 If you selected 24 hour clock system this digital clock allows you to set from 0 00 to 23 59 If the clock or display shows any abnormality unplug the oven from the AC outlet Plug it in again and then reset the clock TIME AM ...

Page 15: ...lay window NOTE If clock is changed from a 12 hour to a 24 hour system or from a 24 hour to a 12 hour system you MUST reset the ALARM in the appropriate 12 or 24 hour system To reset alarm follow instructions listed above Steps 1 4 Otherwise the alarm will not sound at the selected time due to the difference between the two clock systems NOTE If you attempt to enter an incorrect time the time will...

Page 16: ...enter an incorrect time the time will not be set and an error signal will sound COOK HIGH 2 Touch number pads for the cooking time The Time indicator stops blinking The display will show the numbers you pressed in the order you touched AM PM No Oz Alarm On Defrost Cook Cook Low Med High Lock Time AM PM No Oz Alarm On Defrost Cook Cook Low Med High Lock Time 3 Touch START pad When you touch START p...

Page 17: ...larm On Defrost Cook Cook Low Med High Lock Time 2 Touch number pads for the cooking time The Time indicator stops blinking The display will show the numbers you pressed in the order you touched 1 0 0 0 AM PM No Oz Alarm On Defrost Cook Cook Low Med High Lock Time NOTE Your oven can be programmed for 59 min99sec NOTE If you attempt to enter an incorrect time the time will not be set and an error s...

Page 18: ...ring the defrosting cycle to signal that the food needs to be turned or rearranged When the defrosting time ends you will hear 3 beeps START 2 Touch number pads for the defrosting time you want The Time indicator stops blinking The display will show the numbers you pressed in the order you touched 2 6 8 0 AM PM No Oz Alarm On Defrost Cook Cook Low Med High Lock Time NOTE Your oven can be programme...

Page 19: ...When you touch QUICK ON pad 30 is displayed The cooking time appears in the display QUICK ON AM PM No Oz Alarm On Defrost Cook Cook Low Med High Lock Time NOTE You may open the door to stop cooking before the selected time is over To start again close the door and touch START 2 Touch START pad The oven begins cooking and display shows time counting down When the cooking time ends you hear 3 beeps ...

Page 20: ...oking time counting down When the cooking time ends you will hear 3 beeps 2 Touch START pad START AM PM No Oz Alarm On Defrost Cook Cook Low Med High Lock Time Cooking with Preset allows you to cook or reheat many of your favorite foods by touching the appropriate Preset button To increase cooking time touch preset button repeatedly until the correci cooking time appears on the display DO THIS 1 T...

Page 21: ...START pad START AM PM No Oz Alarm On Defrost Cook Cook Low Med High Lock Time ƒR FROZEN PIZZA ƒR 7oz Touch FROZEN PIZZA once 10oz Touch FROZEN PIZZA twice DO THIS 1 Touch BAKED POTATO pad THIS HAPPENS When you touch BAKED POTATO pad 1 is displayed Select number of potatoes as follows BAKED POTATO The display changes to cooking time counting down When the cooking time ends you will hear 3 beeps 2 T...

Page 22: ...AFETY LOCK TO STOP THE OVEN WHILE THE OVEN IS OPERATING The safety lock prevents unwanted oven operation such as by small children To set press and hold STOP CLEAR for 3 seconds LOCK indicator lights To cancel press and hold STOP CLEAR for 3 seclnds LOCK indicator goes off 1 Press STOP CLEAR pad You can restart the oven by touching START pad Touch STOP CLEAR once more to erase all instructions You...

Page 23: ... not closed properly the oven will not operate When the door is closed the hook pushes the button of the micro switch Then the button of the primary interlock switch bring it under on condition Adjustment 1 When the door is closed the switch button is pushed by the hook The movement of the switch button should exceed 1 2mm measured at the top of the button INTERLOCKMECHANISMFUNCTIONSANDADJUSTMENTS...

Page 24: ...two mounting screws b Adjust interlock switch assembly position c Confirm the gap 1 2mm described above d Make sure that push lever moves smoothly after adjustments is completed e Completely tighten the two mounting screws 4 Interlock switch resplacement Whenever safety interlock switches are replaced 1 Refer to the following diagram 2 Check the connection of monitor switch after replacement 3 Per...

Page 25: ... initial and final water temperatures are selected so that the maximum difference between the ambient and final water temperatures is 5K 7 The microwave power output P in watts is calculated from the following formula T is actual temperature rise t is the heating time The power measured should be 600W 10 WARNING Make sure to check the microwave leakage before and after or adjustment Always start m...

Page 26: ...seam is unknow move the probe more slowly When measuring near a corner of the door keep the probe perpendicular to the areas making sure the probe end at the base of the cone does not get closer than 2 inches from any metal If it does erroneous reading may result WIRING DIAGRAM FM POWER SUPPLY SINGLE PHASE ONLY LIVE RD FUSE THERMOSTAT RD RD BK PRIMARY INTERLOCK SWITCH UPPER WH L R RD HIGH VOLTAGE ...

Page 27: ...cools the magnetron by blowing the air coming from the intake on the rear plate hole 3 The oven lamp light the inside of the oven 4 Indicator light turns on to indicate function operation Cooking time starts count down 5 3 3 Volts AC is generated from the filament winding of the high voltage transformer This filament voltage is applied to the magnetron to heat the magnetron filament through two no...

Page 28: ...ose and creats the short circuit 6 If the contacts of primary interlock switch malfunction the 15A fuse blows open due to the large current surge caused by the short circuit activiation and this in turn stops magnetorn oscillation Fig 1 5 When the STOP CLEAR pad is touched during cooking 1 The touch control circuit cuts the voltage supplied to the RELAY 1 coil and causes the magnetron to stop osci...

Page 29: ...ng repaire work 2 Warning about the electric charge in the high voltage capacitor For about 30 seconds after the operation stops electric charge remains in the high voltage capacitor When replacing or checking parts short between oven chassis and the negative high terminal of the high voltage capacitor by using a properly insulated screw driver to discharge 4 When the 15 Amp fuse is blown out due ...

Page 30: ...ove door assembly 1 Remove two screws F41 which secure the top hinge stopper A03 2 Remove the door assembly A00 from top plate 3 Reverse the above for reassembly 3 To remove door parts DISASSEMBLY AND ASSEMBLY F02 F41 A00 A03 A01 A02 A04 A03 A06 A05 A07 A08 ...

Page 31: ... two screws 2 To reduce gap located on part B 1 Loosen three screws on under hinge stopper then push the door to contact the door seal to oven front surface 2 Tighten three screws 3 To reduce gap located on part C See Fig 5 1 Remove the cabinet 2 Loosen a screw on interlock switch assembly located top of oven body 3 Draw the interlock switch assembly inward as possible to engage with hook on the d...

Page 32: ...emove the three screws B04 from the P C B ass y B03 2 Pull out the P C B ass y B03 from the control panel B02 3 Remove the door open lever B05 4 Pull out the door open button B07 and button spring B06 from the control panel B02 5 Reverse the above steps for reassembly NOTE Do not attempt to remove switch membrane except for replacement B01 B02 B03 B04 B05 B06 B07 ...

Page 33: ...move the H V diode F20 from the capacitor holder F18 3 Reverse the above steps for reassembly High voltage circuit wiring 7 To remove magnetron 1 Remove three screws F11 holding the magnetron F10 2 Pull out the magnetron F10 from the wave guide 3 Reverse the above steps for reassembly F20 F18 F17 F19 MAGNETRON H V CAPACITOR H V DIODE H V TRANS F10 F11 ...

Page 34: ...ransformer F21 2 Remove the H V transformer F21 3 Reverse the above steps for reassembly Metallic gasket plate Magnetron antenna Filament terminal Magnetron Cooling fin F16 F15 F14 F12 F13 F12 F22 F21 Wave guide Magnetron antenna Metallic gasket plate CAUTION Never install the magnetron without the metallic gasket plate which is packed with each magnetron to prevent microwave leakage Whenever repa...

Page 35: ...obable defective touch control circuit or membrane switch assembly TROUBLE SHOOTING GUIDE 1 Incomplete segments A Segments missing B Partical segments missing C Digit flickering other than normal fluorescent slight flickering D 0 does not display when power is on 2 A distinct change in the brightness of one or more numbers in the display 3 One or more digits in the display are not on when they sho...

Page 36: ... the trouble shooting guide for the membrane keyboard failure please check for the continuity of each wire harness between the membrane keyboard and control box assembly A B C D E F G H I J K 1 2 3 4 5 6 7 8 9 10 11 PCB Termination PCB Connector DEFROST COOK CLOCK DEFROST COOK 1 2 3 4 5 6 7 8 9 0 STOP CLEAR START AM Defrost Low PM No Or Alam On Defront Low Cook Med Cook High Lock Time Cook Med Coo...

Page 37: ... 4 pad Between G and E 7 3 pad Between G and D 8 2 pad Between G and C 9 1 pad Between G and B 10 0 pad Between G and A 11 STOP CLEAR pad Between K and E 12 CLOCK pad Between K and D 13 DEFROST pad Between K and C 14 COOK pad Between K and B 15 START pad Between K and A 1 9 pad Between F and E 2 8 pad Between F and D 3 7 pad Between F and C 4 6 pad Between F and B 5 5 pad Between F and A 6 4 pad B...

Page 38: ... close Continuity Shorted contacts of primary inter lock switch Check continuity of primary winding of low voltage transformer 0Ω or infinite Shorted or open winding Defective high voltage transformer Approx 90 120Ω normal Disconnect one side of the lead wire connected from transformer to the high voltage capacitor and operate the unit 0Ω or infinite Shorted or open winding Defective high voltage ...

Page 39: ...h Replace Display do not shown countdown Condition Check Cause Result Remedy Turn table motor fan moter and oven lamp do not turn on Check continuity of primary interlock switch No Continuity Malfunction of Primary interlock switch Adjust or replace Approx 24VDC Faulty contacts of RELAY 2 coil Replace Defective touch control circuit Replace Check D C voltage being supplied to RELAY 2 coil 0V TROUB...

Page 40: ...tinuity Check the isolation of filament winding transformer No Good Good Defective high voltage transformer Defective magnetron No Continuity No Continuity Defective magnetron Replace Replace Defective high voltage transformer No Continuity Continuity Continuity Continuity in the reverse direction Defective high voltage diode Replace Check continuity of filament of magnetron Check continuity of fi...

Page 41: ... is low Check the power source voltage with magnetron oscillating Lower than 105 volts Normal Decrease in power source voltage Customer education Check the timing periods of the RELAY 1 coil NOTE 2 Defective touch control circuit Replace Aging change of magnetron Replace depending on the result of output test Abnormal NOTE 3 Condition Check Cause Result Remedy Normal ...

Page 42: ...resistance across the diode terminals Reverse the meter leads and again observe the resistance reading Meter with 6V 9V or higher voltage batteries should be used to check the front back resistance of the diode otherwise an infinite resistance may be read in both directions A normal diodes resistance will be infinite in one direction and several hundred KΩ in the other direction 4 Magnetron For co...

Page 43: ...s interlock monitor switch primary and secondary interlock switches check 1 In case of interlock monitor switch check Condition 1 Door is opened 2 Common terminal of the monitor switch disconnected 2 In case of primary interlock switch check Condition 1 Door is closed PRIMARY INTERLOCK SWITCH INTERLOCK MONITOR SWITCH POWER SUPPLY CORD OHMMETER PRIMARY INTERLOCK SWITCH INTERLOCK MONITOR SWITCH POWE...

Page 44: ...OTE 2 The allowable tolerance of the secondary voltage is within 5 of norminal voltage NOTE Each measure point must be measured with GND points 1 2 10 8 7 6 NO MEASURE POINT WAVE FORM REMEDY REMARK 1 MP1 DC 5V 0 25 Replace ZD2 EC1 EC2 NO LOAD 2 MP2 DC 30V 1 0 Replace R21 ZD3 NO LOAD 3 MP3 DC 27V 1 0 Replace R21 R22 EC5 NO LOAD T 0V 14V T 16 67 ms 60 Hz T 0V 5V T 250ns NO CHECK POINT REMARK 1 IC1 P...

Page 45: ...from G1 to G5 SEGMENT g 15 42 DEFROST COOK don t come on UPPER BAR h 5 33 R15 RY2 D10 A Q5 19 R18 EC3 IC1 EC4 24V Q4 R13 RELAY 2 NO CAUSE MEASUREMENT RESULT REMEDY 1 Poor contact between Check the voltage Fix the PIN 1 25 P C B and display of PIN 1 PIN 25 2 4 VAC filament 2 Defective Display Refer to The display Replace P C B trouble shooting data assembly below 3 Loss of vaccum in white spot Whit...

Page 46: ...45 Fig 9 Measurement Point ...

Page 47: ...unt down timer does not stop CHECK METHOD R10 RY1 D9 B Q3 18 IC1 A B C2 IC1 16 5V R8 R9 D6 SECONDARY INTERLOCK SWITCH CN1 A POINT A STAGE RELAY 2 ON 24VDC RELAY 2 OFF GND POINT A B STAGE RELAY 1 ON 5VDC GND RELAY 1 OFF GND GND POINT A B STAGE RELAY 1 ON 5VDC GND RELAY 1 OFF GND GND CHECK METHOD REMEDY NO 1 Check the stage ON OFF of the secondary Replace secondary Interlock switch by resistance mea...

Page 48: ...6 When the digital clock does not operate properly If clock does not keep exact time you must check resistor R11 R17 47 22 IC1 A C4 R11 R17 D13 D14 D11 D12 POINT WAVEFORM A OV 14V T 16 67 ms ...

Page 49: ...48 2 P C B CIRCUIT DIAGRAM MFM 6D ...

Page 50: ...2 P C B CIRCUIT DIAGRAM MFM 7DTP 49 ...

Page 51: ...50 3 COMPONENT INFORMATION 1 Transistor 2 Diode and Zener Diode Emitter Collector Base Q1 5 DIODE Cathode K ZENER DIODE Cathode K ANODE A D1 7 8 14 ANODE A ZD1 3 ...

Page 52: ...51 4 PRINTED CIRCUIT BOARD ...

Page 53: ...A1270Y 4 18 RESISTOR ARRAY RA1 RGLD6X104J RA 87X104J 1 19 CAPACITOR CERAMIC C4 HIKF 50V 0 01uF Z CCXF1H103Z 1 20 CAPACITOR CERAMIC C1 3 HIKF 50V 0 1uF Z CBXF1H104Z 3 21 CAPACITOR ELECTROLYTIC EC5 220uF 50V RSS CEXF1H471V 1 22 CAPACITOR ELECTROLYTIC EC1 2 47uF 16V RS CEXF1C470A 2 23 CAPACITOR ELECTROLYTIC EC3 0 1uF 50V RS CEXE1H108A 1 24 CAPACITOR ELECTROLYTIC EC4 2 2uF 50V RS CEXE1H229A 1 25 CAPAC...

Page 54: ...03100 BARRIER SCREEN 0 PMMA T0 5 1 A02 3512202200 FRAME DOOR ABS HR 401 H 2938 1 A03 3515201500 STOPPER HINGE T AS KOR 61150S 1 A04 3511706520 DOOR PAINTING AS KOR 81250S 1 A05 3517002900 BARRIER SCREEN I POLYESTER T0 1 1 A06 3512300400 GASKET DOOR PP 1 A07 3513100700 HOOK POM 1 A08 3515101300 SPRING HOOK PW1 1 DOOR ASSEMBLY 3511706402 ...

Page 55: ... 7DTP B02 3516713410 CONTROL PANEL ABS AF 345 HF 700HT 1 B03 PKMPMSR100 PCB MAIN AS KOR 811F2A 1 MFM 6D PKMPMSWK00 KOR 811F 3A MFM 7DTP B04 7122401211 SCREW TAPPING T2S TRS 4X12 MFZN 4 B05 3513702500 LEVER DOOR OPEN POM 1 B06 441G430171 SPRING DOOR BUTTON SWP DIA 0 7 1 B07 3516904410 BUTTON DOOR OPEN ABS AF 345 HF 700HT 1 CONTROL PANEL ASSEMBLY PKCPSWR100 MFM 6D PKCPSWWK00 MFM 7DTP ...

Page 56: ...55 ...

Page 57: ...T3 TRS 4x8 MFZN 1 F18 3513001900 HOLDER HV CAPACITOR SECC T0 8 1 F19 441L267010 CAPACITOR HV 2100VAC 0 07uF 1 F20 4416V24000 DIODE HV SANKEN HVR 1X 32B D5 3 1 F21 3518111700 TRANS HV JMOT N60A0 81T 1 F22 3516003700 SCREW SPECIAL TT3 HEX FG 4x8 MFZN 4 F23 3512100900 FOOT PP DASF 130 2 F24 3510308900 BASE SBHG T0 8 1 F25 7272400811 SCREW TAPTITE TT3 TRS 4x8 MFZN 2 F26 7112401011 SCREW TAPPING T1 TRS...

Page 58: ...DAEWOO ELECTRONICS CO LTD S M NO R821M AM012 686 AHYEON DONG MAPO GU SEOUL KOREA C P O BOX 8003 SEOUL KOREA TELEX DWELEC K28177 8 FAX 02 360 8184 TEL 02 360 8183 PRINTED DATE JUN 1998 ...

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