Read Sharp R-23AM (serv.man3) Service Manual online
4
R - 2 2 A T
R-23AM
R - 2 4 A T
R-23AM
R - 2 4 A T
OPERATION SEQUENCE
the two high voltage transformers. The voltage is
converted to about 3.3 volts A.C. output on the filament
winding and high voltage of approximately 2000 volts
A.C. on the secondary winding.
converted to about 3.3 volts A.C. output on the filament
winding and high voltage of approximately 2000 volts
A.C. on the secondary winding.
2. The filament winding voltage (3.3 volts) heats the
magnetron filament and the high voltage (2000 volts) is
sent to the voltage doubling circuit, where it is doubled
to negative voltage of approximately 4000 volts D.C..
sent to the voltage doubling circuit, where it is doubled
to negative voltage of approximately 4000 volts D.C..
3. The 2450 MHz microwave energy produced in the
magnetron generates a wave length of 12.24 cm. This
energy is channelled through the waveguide (transport
channel) into the oven cavity, where the food is placed
to be cooked.
energy is channelled through the waveguide (transport
channel) into the oven cavity, where the food is placed
to be cooked.
4. When the cooking time is up, a signal tone is heard and
the relays RY3+RY4 (for R-22AT/24AT)/ RY2+RY3
(for R-23AM) go back to their home position. The
circuits to the high voltage transformers T1+T2. The
relay RY1 remains and oven lamp, blower motor and
stirrer motors work for 1 minute.
(for R-23AM) go back to their home position. The
circuits to the high voltage transformers T1+T2. The
relay RY1 remains and oven lamp, blower motor and
stirrer motors work for 1 minute.
5. When the door is opened during a cook cycle, the
switches come to the following condition.
CONDITION
DURING
DURING
DOOR OPEN
SWITCH
CONTACT
COOKING
(NO COOKING)
1st latch switch
COM-NO
Closed
Open
Monitor switch
COM-NC
Open
Closed
2nd latch switch
COM-NO
Closed
Open
Stop switch
COM-NO
Closed
Open
3rd latch switch
COM-NO
Closed
Open
The circuits to the high voltage transformers T1+T2 are
cut off when the 1st latch, 2nd latch, 3rd latch and stop
switches SW1+SW2+SW3+SW5 are made open. The
blower motor BM, stirrer motors and oven lamp re-
mains on even if the oven door is opened after the
cooking cycle has been interrupted, because the relay
RY1 stays closed. Shown in the display is the remain-
ing time, but the program is cancelled if the oven is not
started within 3 minutes.
cut off when the 1st latch, 2nd latch, 3rd latch and stop
switches SW1+SW2+SW3+SW5 are made open. The
blower motor BM, stirrer motors and oven lamp re-
mains on even if the oven door is opened after the
cooking cycle has been interrupted, because the relay
RY1 stays closed. Shown in the display is the remain-
ing time, but the program is cancelled if the oven is not
started within 3 minutes.
6. MONITOR SWITCH CIRCUIT
The monitor switch SW4 is mechanically controlled by
oven door, and monitors the operation of the 1st latch
switch SW1.
oven door, and monitors the operation of the 1st latch
switch SW1.
6-1. When the oven door is opened during or after the
cycle of a cooking program, the 1st, 2nd, 3rd latch and
stop switches SW1+SW2+SW3+SW5 must open their
contacts first. After that the contacts (COM-NC) of the
monitor switch SW4 can be closed.
stop switches SW1+SW2+SW3+SW5 must open their
contacts first. After that the contacts (COM-NC) of the
monitor switch SW4 can be closed.
6-2. When the oven door is closed, the contacts (COM-
NC) of the monitor switch SW4 must be opened first.
After that the contacts (COM-NO) of the 1st, 2nd, 3rd
latch and stop switches SW1+SW2+SW3+SW5 must
be closed.
After that the contacts (COM-NO) of the 1st, 2nd, 3rd
latch and stop switches SW1+SW2+SW3+SW5 must
be closed.
6-3. When the oven door is opened and the contacts of the
1st latch switch SW1 remain closed, remains closed,
the fuse F2 F6.3A will blow, because the monitor
switch is closed and a short circuit is caused.
the fuse F2 F6.3A will blow, because the monitor
switch is closed and a short circuit is caused.
MICROWAVE VARIABLE COOKING (for R-22AT
and R-24AT)
and R-24AT)
When the microwave oven is preset for variable cooking
Closing the door activates all door interlock switches (1st
latch switch, 2nd latch switch, 3rd latch switch and stop
switch).
latch switch, 2nd latch switch, 3rd latch switch and stop
switch).
IMPORTANT
When the oven door is closed, the monitor switch contacts
COM-NC must be open. When the microwave oven is
plugged in a wall outlet (230 - 240 volts, 50Hz), the line
voltage is supplied to the point A5+A7 in the control panel
through the noise filter.
COM-NC must be open. When the microwave oven is
plugged in a wall outlet (230 - 240 volts, 50Hz), the line
voltage is supplied to the point A5+A7 in the control panel
through the noise filter.
Figure O-1 on page 36
1. The digital display shows .
IDLE CONDITION
When the door is opened, the contacts of the 1st. latch
switch SW1, 2nd. latch switch SW2, 3rd. latch switch SW3
and stop switch SW5 open, initiating the following:
switch SW1, 2nd. latch switch SW2, 3rd. latch switch SW3
and stop switch SW5 open, initiating the following:
Figure O-2 on page 36
1. A signal is input to the control unit energizing the coil of
shut-off relay RY-1.
2. The shut-off relay RY-1 contacts close completing
circuits to turn on the oven lamp, blower motor and
stirrer motors.
stirrer motors.
3. If the door remains open, 60 seconds later the control
unit de-energizes shut-off relay RY-1 turning off the
oven lamp, blower motor and stirrer motors.
oven lamp, blower motor and stirrer motors.
When the door is closed, the contacts of the 1st. latch
switch SW1, 2nd. latch switch SW2, 3rd. latch switch SW3
and stop switch SW5 close. With the closing of the stop
switch SW5 contacts, an additional circuit is provided
which will permit the operation of the oven when one of the
touch pads is depressed. Since the control is enabled
through the stop switch SW5, the door must be closed
before the touch pads will be effective. When the door is
closed, a full 60 second IDLE condition is always provided
for selecting and pressing the desired touch pads. A 60
second IDLE condition will also follow the end of each cook
cycle.
switch SW1, 2nd. latch switch SW2, 3rd. latch switch SW3
and stop switch SW5 close. With the closing of the stop
switch SW5 contacts, an additional circuit is provided
which will permit the operation of the oven when one of the
touch pads is depressed. Since the control is enabled
through the stop switch SW5, the door must be closed
before the touch pads will be effective. When the door is
closed, a full 60 second IDLE condition is always provided
for selecting and pressing the desired touch pads. A 60
second IDLE condition will also follow the end of each cook
cycle.
MICROWAVE COOKING CONDITION
for R-22AT and R-24AT
Touch MANUAL/ REPEAT key and enter a desired
cooking time with the touching NUMBER key. And then
touch START key.
cooking time with the touching NUMBER key. And then
touch START key.
Function sequence Figure O-3 on page 37
CONNECTED COMPONENTS
RELAY
Oven lamp/ Blower motor/ Stirrer motors
RY1
High voltage transformer T1
RY3
High voltage transformer T2
RY4
for R-23AM
Enter a desired cooking time with the turning TIME
CONTROL knob. And then push STARTbutton.
CONTROL knob. And then push STARTbutton.
Function sequence Figure O-3 on page 37
CONNECTED COMPONENTS
RELAY
Oven lamp/ Blower motor/ Stirrer motors
RY1
High voltage transformer T1
RY2
High voltage transformer T2
RY3
1. The line voltage is supplied to the primary winding of
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