Dacor DMT2420B Service Manual Download Page 32

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DMT2420B
DMT2420R
DMT2420S

COOLING FAN MOTOR REMOVAL

REMOVAL
1. Disconnect the power supply cord and then remove

outer case.

2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the wire leads from the fan motor.
5. Remove the two (2) screws  holding the fan motor to the

oven cavity back plate.

6. Remove the fan blade from the fan motor shaft according

to the following procedure.

7. Hold the edge of the rotor of the fan motor by using a pair

of groove joint pliers.

CAUTION:
*

Make sure that no metal pieces enter the gap between
the rotor and the stator of the fan motor because the
rotor is easily shaven by pliers and metal pieces may
be produced.

*

Do not touch the pliers to the coil of the fan motor
because the coil may be cut or damaged.

*

Do not disfigure the bracket by touching with the
pliers.

8. Remove the fan blade from the shaft of the fan motor by

pulling and rotating the fan blade with your hand.

9.  Now, the fan blade and the fan motor will be free.

CAUTION:
*

Do not reuse the removed fan blade because the
hole (for shaft) may be larger than normal.

INSTALLATION
1. Install the fan blade to the fan motor shaft according to

the following procedure.

2. Hold the center of the bracket which supports the shaft

of the fan motor on the flat table.

3. Apply the screw lock tight into the hole (for shaft) of the

fan blade.

4. Install the fan blade to the shaft of fan motor by pushing

the fan blade with a small, light weight, ball peen hammer
or rubber mallet.

CAUTION:
*

Do not hit the fan blade hard when installing because
the bracket may be damaged.

*

Make sure that the fan blade rotates smoothly after
installation.

*

Make sure that the axis of the shaft is not slanted.

5. Install the fan motor to the the oven cavity back plate with

the two (2) screws.

6. Connect the wire leads to the fan motor, referring to the

pictorial diagram.

AH SENSOR REPLACEMENT

Removal
1. Disconnect the power supply cord, and then remove

outer case.

2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Remove the two (2) screws holding the AH sensor to the

sensor duct.

5. Disconnect the AH sensor harness from the connector

CN-F on control unit.

6. AH sensor is now free.

Reinstallation
1. Insert the new AH sensor into the sensor duct.
2. Install two (2) screws to secure the AH sensor.
3. Route the AH sensor harness across the oven cavity top

plate and through the large opening.

4. Connect the AH sensor harness to CN-F on control unit.
5. Re-install the outer case cabinet and check for proper

operation.

DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL

1. Disconnect the power supply cord and remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect wire leads from the switches.
5. Remove two (2) screws holding latch hook to oven flange.
6. Remove latch hook assembly from oven flange.
7. Push outward on the two (2) retaining tabs holding switch

in place.

8. Switch is now free.

At this time switch lever will be free, do not lose it.

Re-install
1. Re-install each switch in its place. The secondary interlock/

monitor switches are in the lower position and the door
sensing switch is in the upper position.

2. Re-connect wire leads to each switch.

Refer to pictorial diagram.

Rear View

Gap

Rotor

Bracket

Stator

Groove joint pliers

Coil

Side View

Shaft

Axis

Stator

These are the areas 

that should be held

with a pliers

Rotor

Shaft

Table

Center of

bracket

Summary of Contents for DMT2420B

Page 1: ...IONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY INSIDE FRONT COVER BEFORESERVICING INSIDE FRONT COVER WARNING TO SERVICE PERSONNEL 1 MICROWAVEM...

Page 2: ...operative unit perform a microwave emission check as per the Microwave Measure ment Procedure outlined in this service manual If microwave emissions level is in excess of the specified limit contact...

Page 3: ...tage capacitor 4 Disconnect the leads to the primary of the power transformer 5 Ensure that the leads remain isolated from other components and oven chassis by using insulation tape 6 After that proce...

Page 4: ...er of the oven cavity The water container shall be a low form of 600 ml 20 oz beaker with an inside diameter of approx 8 5 cm 3 1 2 in and made of an electrically nonconductive material such as glass...

Page 5: ...is no other visible damage with the oven Servicing and repair work must be carried out only by trained service personnel DANGER Certaininitialpartsareintentionallynotgroundedandpresent a risk of elec...

Page 6: ...Defrost pad Beverage pad Set Up pad Number selection pads Easy Minute pad Stop Clear pad Start pad New Wave Cookbook pads Oven Cavity Light Yes Safety Standard UL Listed FCC Authorized DHHS Rules CFR...

Page 7: ...1 One touch door open button Push to open door 2 Door latches The oven will not operate unless the door is securely closed 3 Removable turntable support 4 Removable turntable The turntable will rotat...

Page 8: ...power transformer oven lamp etc are turned off and the generationofmicrowaveenergyisstopped Theovenwill revert to the OFF condition 6 Whenthedoorisopenedduringacookcycle themonitor switch door sensing...

Page 9: ...and humidity and calculates cooking time and variable power CookingSequence 1 TouchoneoftheSENSORpadsandthentouchtheStart pad NOTE The oven should not be operated on SENSOR immediately after plugging...

Page 10: ...LAMP WHT SECONDARY INTERLOCK SWITCH TURN TABLE MOTOR WHT A1 120V AC 60Hz N GND GRN C T FUSE RED COM SENSOR CONTROL UNIT BLK H A2 CAVITY TEMP FUSE HUMIDITY N O N C COM ORG BRN ORG WHT WHT F3 F2 F1 B2...

Page 11: ...ontacts CAUTION BEFORE REPLACING A BLOWN C T FUSE TEST THE DOOR SENSING SWITCH PRI MARY INTERLOCK RELAY RY2 RELAY RY1 SECONDARYINTERLOCKSWITCHAND MONITOR SWITCH FOR PROPER OPERA TION REFER TO CHAPTER...

Page 12: ...BA019 KIT as an assembly IMPORTANT Whenever troubleshooting is performed with the power supply cord disconnected It may in some cases be necessary to connect the power supply cord after the outer case...

Page 13: ...plugged into wall receptacle Monitor fuse blows when power cord is plugged into wall receptacle Any letters or indicators do not appear in display when power cord is first plugged into wall outlet Dis...

Page 14: ...ultymagnetronandthereisnodefectinthefollowing componentsorwiring siliconrectifier highvoltagecapacitorandpowertransformer Thistestwillrequire a 16 ounce 453cc measuring cup and an accurate mercury the...

Page 15: ...cabinet 7 Reconnect the power supply cord after the outer case is installed 8 Run the oven and check all functions NOTE Be sure to use an ohmmeter that will supply a forward bias voltage of more than...

Page 16: ...ter should indicate an open circuit with the door open and a closed circuit with the door closed If improper operation is indicated replace the door sensing switch 5 Reconnect all leads removed from c...

Page 17: ...er pad two figures or more are displayed c When touching the pads sometimes a pad produces no signal If the Key unit is defective H TOUCH CONTROL PANEL ASSEMBLY TEST 1 Disconnect the power supply cord...

Page 18: ...isconnect the power supply cord and then remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Reconnect all leads removed from components during testing 5 Re instal...

Page 19: ...ling fan motor RY2 Approx 23 0V D C Power transformer 8 Disconnect the power supply cord and then remove outer case 9 Open the door and block it open 10 Discharge high voltage capacitor 11 Reconnect a...

Page 20: ...ions 2 Followthetroubleshootingguidegivenbelow ifindicatordoesnotlightupafterabovecheckandrepairs are finished 1 Disconnect the power supply cord and then remove outer case 2 Open the door and block i...

Page 21: ...ad cooking test WARNING The oven should be fully assembled before following procedure Makesuretheovenhasbeenpluggedinatleasttwominutesbeforecheckingsensorcookoperation The cabinet should be installed...

Page 22: ...padonce thePowerLevelpadtwice theStartpadonceandthenumber pad 1 once 9 2 The control panel is in the sensor cooking operation 9 3 After approximately 25 seconds push plunger of select switch for more...

Page 23: ...e function that was requested The touch control section consists of the following units 1 Key Unit 2 Control Unit TheControlUnitconsistsofPowerUnitand LSI Unit Theprincipalfunctionsoftheseunitsandthes...

Page 24: ...rminal not used 13 Vss IN Powersourcevoltage GND 0V The power source voltage to drive LSI is input to Vss terminal 14 TxD0 OUT Data signal is output to a memory IC IC4 15 P91 OUT Clock signal is outpu...

Page 25: ...voltage to drive LSI is input to Vss terminal 47 58 A8 A19 OUT Address signal is output to IC2 and IC5 59 Vss IN Power source voltage GND 0V The power source voltage to drive LSI is input to Vss termi...

Page 26: ...or open close information to LSI Door close H level signal 5V Door open L level signal GND 85 AN5 IN Used for initial balancing of the bridge circuit absolute humidity sensor This input is an analog i...

Page 27: ...in such a way as to change the resistance values in parallel with R98 R102 Changing the resistance values results in that there is the same potential at both F 3 terminal of the absolute humidity sen...

Page 28: ...en the touch control panel and the oven itself is so short that the two can t be separated For those models check and repair all the controls sensor related ones included of the touch control panel wh...

Page 29: ...ING FOR WIRING 1 Disconnect the power supply cord 2 Make sure that a definite click can be heard when the microwave oven door is unlatched Hold the door in a closed position with one hand then push th...

Page 30: ...ment lead short one of the power transformer from the high voltage capacitor 7 Remove one 1 screw holding capacitor holder with the high voltage rectifier to the base plate 8 Disconnect rectifier term...

Page 31: ...e the LSI unit carefully so that there is no excessive force applied to the ribbon connection LSI unit 1 Disconnect the power supply cord 2 Removeturntableandturntablesupportfromovencavity 3 Lay the o...

Page 32: ...s smoothly after installation Make sure that the axis of the shaft is not slanted 5 Install the fan motor to the the oven cavity back plate with the two 2 screws 6 Connect the wire leads to the fan mo...

Page 33: ...oor sensing switch secondary interlock switch and monitorswitchdonotoperateproperlyduetoamisadjustment the following adjustment should be made 4 Loosen the two 2 screws holding latch hook to the oven...

Page 34: ...door glass into the five 5 tabs of the door frame 1 3 Slidethedoorglassleftwardsandinserttheleftedgeof door glass into the two 2 tabs of the door frame 2 Re installthedoorglassstoppertothedoorframesot...

Page 35: ...NOTE The neutral WHT GRY wire must be connected to the terminal with N mark on the power supply cord RED WHT BRN RED WHT WHT ORG WHT RED RED PNK GRN GRN to Oven cavity WHT WHT WHT WHT BLUE MARK RED CA...

Page 36: ...N BUZZR MICRO N C N C AC MICRO OVEN LAMP FAN MOTOR TURNTABLE MOTOR OVEN LAMP FAN MOTOR TURNTABLE MOTOR DOOR SENSING SWITCH NOTE IF NOT SPECIFIED 0 1 F 50V DOOR SENSING SWITCH AC120V 60Hz CN A CN C 11P...

Page 37: ...F3 C11 C10 C9 C7 C8 C2 C1 C5 VR VA GND INT AH SENSOR BUZZER ENV BUZZER OVEN LAMP TURNTABLE MOTOR FAN MOTOR MICROR NC NC DOOR SENSING SWITCH CN C G 5 G 1 SETUP PASTA GRAINS DEFROST FROZEN FOOD EASY MIN...

Page 38: ...1 2 3 A B C D E F G H A B C D E F G H Figure S 4 Printed Wiring Board of Power Unit R3 CN C Q1 SH A GREEN E B R2 D20 XA VH QKITPB033MREO J1 VRS1 CN A R1 ZD1 C2 C1 VH CN B SH B SP30 RY1 RY2 D21 T1 P S...

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