Dacor DCM24B Service Manual - Warning to Service Personnel

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Manual is about: CONVECTION MICROWAVE OVEN

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DCM24B

DCM24R

DCM24S

WARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of pro-

ducing very high voltage and current, contact with

following parts may result in a severe, possibly

fatal, electrical shock.

(Example)

High Voltage Capacitor, High Voltage Power Trans-

former, Magnetron, High Voltage Rectifier Assem-

bly, High Voltage Harness etc..

Read the Service Manual carefully and follow all

instructions.

Before Servicing

1. Disconnect the power supply cord

, and then

remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

WARNING:RISK OF ELECTRIC SHOCK.

DISCHARGE THE HIGH-VOLTAGE

CAPACITOR BEFORE SERVICING.

The high-voltage capacitor remains charged about 60

seconds after the oven has been switched off. Wait for 60

seconds and then short-circuit the connection of the high-

voltage capacitor (that is the connecting lead of the high-

voltage rectifier) against the chassis with the use of an

insulated screwdriver.

Whenever troubleshooting is performed the power supply

must be disconnected. It may, in some cases, be necessary

to connect the power supply after the outer case has been

removed, in this event,

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 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 procedure, reconnect the power supply cord.

When the testing is completed,

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. Reconnect the leads to the primary of the power

transformer.

5. Reinstall the outer case (cabinet).

6. Reconnect the power supply cord after the outer case is

installed.

7. Run the oven and check all functions.

After repairing

1. Reconnect all leads removed from components during

testing.

2. Reinstall the outer case (cabinet).

3. Reconnect the power supply cord after the outer case is

installed.

4. Run the oven and check all functions.

Microwave ovens should not be run empty. To test for the

presence of microwave energy within a cavity, place a cup

of cold water on the oven turntable, close the door and set

the power to HIGH and set the microwave timer for two (2)

minutes. When the two minutes has elapsed (timer at zero)

carefully check that the water is now hot. If the water

remains cold carry out Before Servicing procedure and re-

examine the connections to the component being tested.

When all service work is completed and the oven is fully

assembled, the microwave power output should be checked

and a microwave leakage test should be carried out.

Don't Touch !

Danger High Voltage

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Summary of DCM24B

Page 1
Dcm convection microwave parts and service manual.
Page 2: Convection
47 dcm24b dcm24r dcm24s table of contents convection microwave oven models dcm24b dcm24r dcm24s in the interest of user-safety the oven should be restored to its original condition and only parts identical to those specified should be used. Warning to service personnel: microwave ovens contain circu...
Page 3: Before Servicing
48 dcm24b dcm24r dcm24s precautions to be observed before and during servicing to avoid possible expo- sure to excessive microwave energy (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 mag...
Page 4: Warning to Service Personnel
1 dcm24b dcm24r dcm24s warning to service personnel microwave ovens contain circuitry capable of pro- ducing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (example) high voltage capacitor, high voltage power trans- former, magne...
Page 5
2 dcm24b dcm24r dcm24s microwave measurement procedure a. Requirements: 1) microwave leakage limit (power density limit): the power density of microwave radiation emitted by a microwave oven should not exceed 1mw/cm 2 at any point 5cm or more from the external surface of the oven, measured prior to ...
Page 6: Service Manual
3 dcm24b dcm24r dcm24s product description general information operation troubleshooting guide and test procedure touch control panel component replacement and adjustment procedure wiring diagram parts list distinctive appliance corporation service manual convection microwave oven dcm24b/ dcm24r/ dc...
Page 7
4 dcm24b dcm24r dcm24s specification item description power requirements 120 volts 13.0 amperes (microwave) / 13.0 amperes (convection) 60 hertz / single phase, 3 wire grounded power output 900 watts (iec test procedure) operating frequency of 2450mhz convection power output 1450 watts case dimensio...
Page 8
5 dcm24b dcm24r dcm24s that a separate circuit serving only this appliance be provided. When installing this appliance, observe all applicable codes and ordinances. A short power-supply cord is provided to reduce risks of becoming entangled in or tripping over a longer cord. Where a two-pronged wall...
Page 9
6 dcm24b dcm24r dcm24s operation description of operating sequence the following is a description of component functions during oven operation. Off condition closing the door activates the door sensing switch and secondary interlock switch. (in this condition, the monitor switch contacts are opened....
Page 10
7 dcm24b dcm24r dcm24s damper switch contacts. The opening of the damper switch contacts sends a signal to the lsi on the control unit de-energizing the relay (ry4) and opening the circuit to the damper motor. 3. The coil of heater relay (ry3) is energized by the control unit and the main supply vol...
Page 11
8 dcm24b dcm24r dcm24s 2. Heat potatoes. Moisture and humidity is emitted rapidly. You can smell the aroma as it cooks. 3. Sensor detects moisture and humidity and calculates cooking time and variable power. Cooking sequence. 1. Touch ensor cook, sensor reheat or popcorn pad. Note: the oven should n...
Page 12
9 dcm24b dcm24r dcm24s figure o-2. Oven schematic-microwave cooking condition schematic 1. Door closed. 2. Cooking time programmed. 3. “start” pad touched. Figure o-1. Oven schematic-off condition schematic note: condition of oven 1. Door closed. 2. Clock appears on display. Schematic diagram conv. ...
Page 13
10 dcm24b dcm24r dcm24s description and function of components schematic 1. Door closed. 2. Convection pad touched. 3. Desired temp. Touched. 4. Cooking time programmed. 5. “start” pad touched. Schematic 1. Door closed. 2. Mix cooking pad touched. 3. Cooking time programmed. 4. “start” pad touched. ...
Page 14
11 dcm24b dcm24r dcm24s failure, obstructed air guide, dirty or blocked air intake, etc. Under normal operation, the temperature fuse remains closed. However, when abnormally high temperatures are reached within the magnetron, the temperature fuse will open at 302˚f(150˚c) causing the oven to shut d...
Page 15
12 dcm24b dcm24r dcm24s convection cooking: damper is in the closed position, so that no hot air will be allowed to leak out the oven cavity. Damper operation 1. When power supply cord is plugged in: 1-1. When power supply cord is plugged in, a signal is sensed in the control unit, and operates shut...
Page 16
13 dcm24b dcm24r dcm24s a magnetron b power transformer c h.V. Rectifier assembly d high voltage capacitor e secondary interlock switch f primary interlock system g monitor switch h monitor fuse i magnetron temperature fuse j conv. Thermal cut-out k convection heater l thermistor m damper motor n da...
Page 17
14 dcm24b dcm24r dcm24s test procedures procedure letter component test 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. To test for an open filament, isolate the magnetron from the high voltage circuit. A co...
Page 18
15 dcm24b dcm24r dcm24s c high voltage rectifier test 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. Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance acr...
Page 19
16 dcm24b dcm24r dcm24s test procedures procedure letter component test 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. Note: if the door sensing switch contacts fail in the open position and the door is closed, the turntable motor and o...
Page 20
17 dcm24b dcm24r dcm24s test procedures procedure letter component test i magnetron temperature fuse test 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. A continuity check across the temperature fuse termin...
Page 21
18 dcm24b dcm24r dcm24s 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 leads to the primary of the power transformer. 5. Ensure that the leads remain isolated from other components and oven c...
Page 22
19 dcm24b dcm24r dcm24s p touch control panel assembly test the touch control panel consists of circuits including semiconductors such as lsi, ics, etc. Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter and ohmmeter. In this service manual, ...
Page 23
20 dcm24b dcm24r dcm24s test procedures procedure letter component test 2-1 in connection with pads. A) when touching the pads, a certain group of pads do not produce a signal. B) when touching the pads, no pads produce a signal. 2-2 in connection with indicators a) at a certain digit, all or some s...
Page 24
21 dcm24b dcm24r dcm24s test procedures procedure letter component test 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 leads to the primary of the power transformer. 5. Ensure that these lead...
Page 25
22 dcm24b dcm24r dcm24s test procedures procedure letter component test 4) follow the troubleshooting guide given below for repair. Steps occurrence cause or correction 1 only pattern at "a" is broken. *insert jumper wire j1 and solder. 2 pattern at "a" and "b" are broken. *insert the coil rcilf2003...
Page 26
23 dcm24b dcm24r dcm24s test procedures procedure letter component test (5) be sure the exterior of the cooking container and the interior of the oven are dry. Wipe off any moisture with a dry cloth or paper towel. (6) the sensor works with food at normal storage temperature. For example, chicken pi...
Page 27
24 dcm24b dcm24r dcm24s test procedures procedure letter component test 9-3. After approximately 20 seconds, push plunger of select switch for more than 3 seconds. This condition is same as judgement by ah sensor. 9-4. After approximately 3 seconds, the display shows “ x x . X x “ which is the remai...
Page 28
25 dcm24b dcm24r dcm24s the touch control section consists of the following units as shown in the touch control panel circuit. (1) key unit (2) control unit the principal functions of these units and the signals com- municated among them are explained below. Key unit the key unit is composed of a ma...
Page 29
26 dcm24b dcm24r dcm24s pin no. Signal i/o description 5 an7 in used for initial balancing of the bridge circuit (absolute humidity sensor). This input is an analog input terminal from the ah sensor circuit, and connected to the a/d converter built into the lsi. 6 an6 in ah sensor input. This input ...
Page 30
27 dcm24b dcm24r dcm24s pin no. Signal i/o description 18 p50 out damper motor relay driving signal. To turn on and off shut-off relay(ry4). 19 p47 out heating element driving signal. To turn on and off shut-off relay(ry3). "l" level during convection cooking; "h" level otherwise. Dur- ing convectio...
Page 31
28 dcm24b dcm24r dcm24s pin no. Signal i/o description 37 p23 out segment data signals. The relation between signals and indicators are as follows: signal segment signal segment signal segment signal segment p23 ............. P1 p17 ............. P5 p13 ............. P9 p07 ........... P13 p22 ........
Page 32
29 dcm24b dcm24r dcm24s (1) structure of absolute humidity sensor the absolute humidity sensor includes two thermistors as shown in the illustration. One thermistor is housed in the closed vessel filled with dry air while another in the open vessel. Each sensor is provided with the protective cover ...
Page 33
30 dcm24b dcm24r dcm24s 1. Precautions for handling electronic components this unit uses cmos lsi in the integral part of the circuits. When handling these parts, the following precautions should be strictly followed. Cmos lsi have extremely high imped- ance at its input and output terminals. For th...
Page 34
31 dcm24b dcm24r dcm24s to remove the outer case, proceed as follows. 1. Disconnect the power supply cord. 2. Open the oven door and block it open. 3. Remove the two (2) screws from the lower portion of the rear cabinet using a t20h torx type or gtxh20-100 screw driver. 4. Remove the remaining two (...
Page 35
32 dcm24b dcm24r dcm24s 1. Disconnect the power supply cord and then remove outer case. 2. Open the oven door and block it open. 3. Discharge high voltage capacitor. 4. Disconnect the high voltage wire leads and rectifier high voltage capacitor removal high voltage rectifier assembly removal 5. Disc...
Page 36
33 dcm24b dcm24r dcm24s 1. Disconnect the power supply cord. 2. Remove the turntable tray, and the turntable support out of the oven cavity. 3. Turn the oven upside down and remove one (1) screw holding the turntable motor cover to the base plate and take off the turntable motor cover. Turntable mot...
Page 37
34 dcm24b dcm24r dcm24s control panel assembly and control unit removal to remove the control panel, procedure as follows: 1. Disconnect the power supply cord and then remove outer case. 2. Open the oven door and block it open. 3. Discharge high voltage capacitor. 4. Disconnect connector cn-a, cn-e ...
Page 38
35 dcm24b dcm24r dcm24s door sensing switch/secondary interlock switch and monitor switch removal 1. Disconnect the power supply cord and then remove outer case. 2. Open the oven door and block it open. 3. Discharge high voltage capacitor. 4. Remove the control panel assembly, refer to "control pane...
Page 39
36 dcm24b dcm24r dcm24s door replacement and adjustment removal 1. Disconnect the power supply cord and then remove outer case. 2. Open the oven door and block it open. 3. Discharge high voltage capacitor. 4. Remove turntable tray and turntable support from oven cavity. 5. Remove three (3) screws ho...
Page 40
37 dcm24b dcm24r dcm24s remove door assembly, refer to "door replacement". Replacement of door components are as follows: choke cover 1. Place door assembly on a soft cloth with latches facing up. Note: as the engaging part of choke cover and door panel are provided at several places, do not force a...
Page 41
38 dcm24b dcm24r dcm24s 6 4 5 1 2 3 6 4 5 1 2 3 a b c d e f g h a b c d e f g h figure s-1. Pictorial diagram turntable motor gry brn org grn red blk damper motor cooling fan motor red blk oven thermal cut-out magnetron temperature fuse gry ic-1 red 1 2 3 4 5 6 pnk red grn wht ppl 1 2 3 4 5 6 7 8 9 ...
Page 42
39 dcm24b dcm24r dcm24s 6 4 5 1 2 3 6 4 5 1 2 3 a b c d e f g h a b c d e f g h figure s-2. Control panel circuit + – + – + – + – + – + – a 9 a 7 a 1 a 3 a 5 e 1 e 2 e 5 e 6 e 3 e 4 f 1 f 2 f 3 g 1 g 2 g 3 g 4 g 5 g 6 g 7 g 8 g 9 g10 g11 g12 n o n o n o com com com vrs1 c1 0.1 µ /50v c22 0.1 µ /50v ...
Page 43
Technical service 950 s. Raymond ave pasadena, ca 91105 800-353-2267.