View Sharp R-82STM (serv.man2) Service Manual online
2) Replace the outer case (cabinet).
3) Reconnect the supply.
4) Run the oven. Check all functions.
and microwave leakage test carried out.
will result in electrocution:-
High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier, High voltage wires.
2) Door opened, and wedged open.
3) Discharge high voltage capacitor.
seconds and then short-circuit the connection of the high-voltage capacitor (that is, of the connecting lead of the high-
voltage rectifier) against the chassis using a screwdriver with an insulated handle.
may be necessary to connect the supply with the cover removed to carry out fault investigation in the control circuitry.
In such cases, the high voltage circuit should be disabled as described below to reduce the hazards:-
connectors, ensuring they are positioned away from the transformer and fastened there.
place a cup of cold water on the oven turntable, close the door and set the microwave timer for one (1) minute, set the
power level to HIGH (100%) and push the start key. When the one (1) minute has elapsed (timer at zero) carefully check
that the water is now hot.
and monitor switch before replacing the fuse F8A.
1) Disconnect the supply.
2) Open the door and wedge open.
3) Discharge the high voltage capacitor.
b) Parts that become hot.
c) Sharp edges.
d) Movable parts.
3) Wires are connected correctly as per pictorial diagram.
4) No wire leads are trapped by the outer wrap.
trained service engineers.
diagram have voltages in excess of 250V.
damaged, loosened or removed.
magnetron or other parts conducting microwave
energy. All input and output microwave connections,
waveguides, flanges and gaskets must be secured.
Never operate the device without a microwave
energy absorbing load attached. Never look into an
open waveguide or antenna while the device is
705) Operating fequency 2450 MHz
Microwave Cooking Control
(monitored latch switch and stop switch).
When the oven door is closed, the contacts COM-NC of the
monitor switch SW2 must be open and the contacts (COM-
NO) must be closed. When the microwave oven is plugged
in a wall outlet (230-240V / 50Hz), 230-240 volts A.C. is
supplied to the point A1 + A3 in the control unit.
2. To set any programmes or set the clock, you must first
NOTE: When the oven door is opened, the oven lamp
Enter a desired cooking time with the Time keys and start the
oven with touching START key.
the relays RY1 + RY2 + RY5 go back to their home
position. The circuits to the oven lamp, high voltage
transformer, fan motor and turntable motor are cut off.
contact of relay RY2 contacts COM-NO of the monitored
latch switch SW1, and monitor switch SW2 are made open.
The circuit to the fan motor is cut off when the relay RY5 is
made open. The circuit to the turntable motor is cut off when
the contacts COM-NO of the monitor switch are made open.
The relay RY2 and RY5 are made open when the door is
opened. The oven lamp remains 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 remaining
3. MONITOR SWITCH CIRCUIT
the oven door, and monitors the operation of the monitored
latch switch SW1.
and stop switch SW3 must open their contacts (COM-
monitor switch SW2 can be closed and the contacts
(COM-NO) of monitor switch SW2 are made open.
contacts (COM-NO) of monitor switch SW2 must be
closed. After that the contacts of the monitored latch
switch SW1 and the stop switch SW3 are made closed.
F8A will blow. Because the relay RY1 and monitor
switch SW2 are closed and a short circuit is caused.
power, the 230-240 volts A.C. power is supplied to the high
voltage transformer intermittently within a 32-second time
base through the relay contact which is coupled with the
current-limiting relay RY2. The following levels of microwave
power are given.
oven cavity in microwave cooking condition.
LSI measures the voltage across the temperature measure-
ment circuit intermittently within a 32-second time base once
the oven is started in the microwave cooking mode. The oven
will stop its operation when the difference of the voltages is
more than 0.69 volts in microwave cooking condition.
energized, the voltage across the temperature
measurement circuit is measured. And after 21 seconds
since the thermistor is cut off, the convection motor
operates for 10 seconds.
judges it is a fire in the oven cavity and stops the oven.
Because food cannot be cooked well by rotating the
convection fan at that time. After sensing the steam, the
sensing fire operation is started.
convection motor and LSI stops counting down. And then
the damper is closed so that the fresh air does not come
into the oven cavity.
procedure can be found in the Sharp Technical Training notes which is available from Sharp Parts Centre
(part number SERV-LITMW01).
make the procedure unsuitable for routine performance checks.
1. Place 2 litres of cold water (between 12
4. When the 2 minutes is completed, remove the container and stir the water. Note the water temperature as T2.
5. Calculate the output power using the following formula:
described in the Sharp Technical Training notes (part number SERV-LITMW01). The maximum leakage permitted in
BS EN 60335-2-25 is 50W/m