14
SMD2470ASY
SMD3070ASY
C RELAY TEST
4) Reconnect all leads removed from components during testing.
5) Re-install the covers.
6) Reconnect the power supply cord after the covers are installed.
7) Run the oven and check all functions.
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
B
KEY UNIT TEST
1. Disconnect the power supply cord, and then remove outer case.
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 leads remain isolated from other components and oven chassis by using insulation
tape.
6. After that procedure, re-connect the power supply cord.
7. Remove the outer case and check voltage between pins A1~A2 which should equal 120Vac with an
A.C. voltmeter , then pins C1-C5 which should be 24Vdc on the power unit with an D .C. voltmeter.
The meter should indicate both the 120 volts AC and 24 volts DC , if not check the switching power
supply voltages (and harness wires for break/ shorts). If it you have the voltages as stated above
and there is still no operation then check oven circuit RY1, RY2, RY3 and RY4 Relay Test
These relays are operated by D.C. voltage. Check voltage at the relay coil with a D.C. voltmeter
during the microwave cooking operation. DC. voltage indicated Defective relay.
DC. voltage not indicated Check diode which is connected to the relay coil. If diode is good, then
the control unit is defective.
RELAY SYMBOL
OPERATIONAL VOLTAGE
CONNECTED COMPONENTS
RY1
Approx. 26V D.C.
Oven lamp / Common
RY2
Approx. 25V D.C.
Power transformer
RY3
Approx. 26V D.C.
Stirrer motor
RY4
Approx. 26V D.C.
Fan motor
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 all leads removed from components during testing.
2. Open the drawer and block it open.
3. Discharge high voltage capacitor.
4. If the display fails to clear when the STOP/CLEAR pad is depressed,
first verify the flat ribbon cable is making good contact, verify that
the door sensing switch (stop switch) operates properly; that is the
contacts are closed when the drawer is closed and open when the
drawer is open. If the door sensing switch (stop switch) is good,
disconnect the flat ribbon cable that connects the key unit to the
control unit and make sure the drawer sensing switch is closed
(either close the drawer or short the door sensing switch connecter).
Use the Key unit matrix indicated on the control panel schematic
and place a jumper wire between the pins that correspond to the
STOP/CLEAR pad making momentary contact. If the control unit
responds by clearing with a beep the key unit is faulty and must be
replaced. If the control unit does not respond, it is faulty and must be
replaced. If a specific pad does not respond, the above method may
be used (after clearing the control unit) to determine if the control
unit or key pad is at fault.
5. Reconnect all leads removed from components during testing.
6. Re-install the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
L-1
L-2
L-3
L-4
L-5
L-6
L-7
L-8
L-9
L-12
L-11
L-10
CN-L
OPEN
CLOSE
7
COOK
START
(+30 Sec)
TIMER
CLOCK
STOP
CLEAR
1
4
DEFROST
HELP/
SETTINGS
KEEP
WARM
8
5
2
3
POPCORN
BEVERAGE
MELT/
SOFTEN
9
POTATOES
6
POWER
LEVEL
0
REHEAT
VEGATABLES
