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1

This Manual has been prepared to provide Sharp Corp. Service
engineers with Operation and Service Information.

It is recommended that service engineers carefully study the
entire text of this manual, so they will be qualified to render
satisfactory customer service.

Service engineers should not be exposed to the microwave
energy which may radiate from the magnetron or other microwave
generating devices if it is improperly used or connected. 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 energized.

Never operate the oven until the following points are en-
sured.
(A) The door is tightly closed.
(B) The door brackets and hinges are not defective.
(C) The door packing is not damaged.
(D) The door is not deformed or warped.
(E) There is not any other visible damage with the oven.

Servicing and repair work must be carried out only by
trained service engineers.

All the parts marked "*" on parts list are used at voltages
more than 250V.

Removal of the outer wrap gives access to potentials above
250V.

All the parts marked "

∆" on parts list may cause undue

microwave exposure, by themselves, or when they are
damaged, loosened or removed.

TEST PROCEDURE

SERVICING AND
TROUBLESHOOTING CHART

FUNCTION OF IMPORTANT
COMPONENTS

OPERATING SEQUENCE

APPEARANCE VIEW

PRODUCT SPECIFICATIONS

WIRING DIAGRAM

PARTS LIST

MICROWAVE MEASUREMENT

CONTROL PANEL ASSEMBLY

COMPONENT REPLACEMENT
 AND ADJUSTMENT PROCEDURE

2

THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:

GREEN-AND-YELLOW

: EARTH

BLUE

: NEUTRAL

BROWN

: LIVE

Power Requirements

230 - 240 Volts / 50 Hertz / Single phase, 3 wire earthed

Power Consumption

Microwave cooking

1.65 kW Approx. 7.2 A

Oven cooking

2.7 kW Approx. 11.3 A

Speed cooking

2.8 kW Approx. 11.7 A

Power Output

900 W nominal of RF microwave energy (measured by method of IEC 60705)
Operating fequency 2450 MHz

Top heating element Power Output

1500 W

Side heating element Power Output

1000 W

Case Dimensions

Width 550 mm

Height 420 mm (including foot)

Depth 640 mm

Cooking Cavity Dimensions

Width  408 mm

Height 214 mm

Depth 345 mm

Turntable diameter

330 mm

Control Complement

Touch Control System

Timer (0 - 99 minutes 99 sec.)

Microwave Power for Variable Cooking

 Repetition Rate;

100 PERCENT ........................................ Full power throughout the cooking time

90 PERCENT ........................................................... approx.  90% of Full Power
80 PERCENT ........................................................... approx.  80% of Full Power
70 PERCENT ........................................................... approx.  70% of Full Power
60 PERCENT ........................................................... approx.  60% of Full Power
50 PERCENT ........................................................... approx.  50% of Full Power
40 PERCENT ............................................................ approx. 40% of Full Power
30 PERCENT ............................................................ approx. 30% of Full Power
20 PERCENT ........................................................... approx.  20% of Full Power
10 PERCENT ............................................................ approx. 10% of Full Power

0 PERCENT ......................................... No power throughout the cooking time

Convection temperature control range:

   250˚C, 230˚C, 220˚C, 200˚C, 190˚C, 180˚C, 160˚C, 130˚C, 100˚C and 40˚C

SPEED GRILL key, LESS/MORE keys, SPEED CONVECTION key
NUMBER keys, HOLD key, OVEN (˚C) key, MICROWAVE key
MANUAL/REPEAT key, PAUSE key, STOP/CLEAR key
SET key, CHECK key, START key

Set Weight

Approx. 39.5 kg

3

DEGITAL DISPLAY INDICATORS:
1. Indicators

   : SPEED
CONVECTION
MICRO
MORE(   )/LESS(   )
CHECK
PAUSE

150˚C

: HOLD 150

°C

COOK

OPERATING KEYS:
2. SPEED GRILL

Press to select speed grill mode.

3. SPEED CONVECTION

Press to select speed convection mode.

4. MORE(   )/LESS(   )

Press to set more or less mode.

1. Control panel
2. Waveguide cover
3. Oven lamp
4. Oven cavity
5. Coupling
6. Door latches
7. Door opening handle

(To open the door, pull the handle down
and forward. Never hold the door handle
when moving the oven.)

8. Door seals and sealing surfaces
9. Ventilation cover
10. Outer cabinet

11. SET

Press to select the oven sound and set
or clear memory programmes.
Press to change the holding time of
HOLD 150

°C.

12. CHECK

Press to check memory banks.

13. START

Press to start oven after setting
programmes.
Press to extend the cooking time by 1
minute multiples using the last
sequence after the cooking.

14. STOP/CLEAR

Press to clear during programming.
Press once to stop operation of oven
during cooking, press twice to cancel
cooking programme.

15. Turntable support
16. Low rack
17. High rack
18. Splash guard

12

13

9

10

11

12

11. Power cord
12. Air-vent openings
13. Oven lamp access cover
14. Turntable

5. NUMBER

Press to select memory number.
Press to enter cooking time.

6. HOLD 150

°C

Press to set or cancel HOLD150

°C

mode.

7. OVEN (

°C)

Press to select convection temperature.

8. MICROWAVE

Press to select microwave power
setting.

9. MANUAL/REPEAT

Press to set manual cooking or select
the repeat cooking mode.

10. PAUSE

Press to set a pause when setting a
sequence programme.

When this commercial  microwave oven is installed near other commercial electrical appliances, connect a lead wire to each equivalent
potential terminal with equipotential marking between them (insert a lead wire between a washer and an earth angle, and screw them),
as shown in Fig. A-1, to make sure that they are at equivalent potential.
If any lead wire is not connected between them, when person touch them he/she will get a electric shock.

COMMERCIAL MICROWAVE OVEN

OTHER COMMERCIAL 
ELECTRICAL APPLIANCE

Lead wire

Equipotential marking

Earth angle
(Equivalent potential terminal)

Equivalent 
potential terminal

Screw

Washer

Lead wire

4

The following is a description of component functions during
oven operation.

Closing the door activates the door sensing switch and second-
ary interlock switch and 3rd. latch switch. (In this condition, the
monitor switch contacts are opened.)

1. The display will show "   .          ".
NOTE: When the door is opened, the oven lamp comes on.

HIGH COOKING
Press the MANUAL/REPEAT key. Program desired cooking
time by touching the NUMBER keys. Then press the MICRO-
WAVE key once. When the START key is touched, the following
operations occur:

1. The contacts of relays are closed and components connected

to the relays are turned on as follows.
(For details, refer to Figure O-2)

RELAY

CONNECTED COMPONENTS

RY-1

Oven lamp/Turntable motor

RY-2

High voltage transformer

RY-5

Fan motor

2. The line voltage is supplied to the primary winding of the high

voltage transformer. 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.

3. 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..

4. The 2450 MHz microwave energy produced in the magnetron

generates a wavelength 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.

5. When the cooking time is up, a signal tone is heard and 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.

6. When the oven door is opened during a cooking cycle, the

switches come to the following condition.

Switch

Contact

          Condition
During

Oven Door

Cooking

Open(No cooking)

Secondary interlock
switch

COM-NO

Closed

Opened

Door sensing switch

COM-NO

Closed

Opened

3rd. latch switch

COM-NO

Closed

Opened

Monitor Switch

COM-NC

Opened

Closed

The circuit to the high voltage transformer is cut off when the
contacts of relay RY2, and the contacts (COM-NO) of the
secondary interlock switch 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 secondary interlock switch are made open.
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 time.

7. MONITOR SWITCH CIRCUIT

The monitor switch is mechanically controlled by the oven
door, and monitors the operation of the secondary interlock
switch and the relay RY2.

7-1. When the oven door is opened during or after the cycle of

a cooking program, the secondary interlock switch and the
door sensing switch must open their contacts (COM-NO)
first. After that the contacts (COM-NC) of the monitor
switch can be closed and the contacts (COM-NO) of 3rd.
latch switch are made open.

7-2. When the oven door is closed, the contacts (COM-NC) of

the monitor switch must be opened and the contacts
(COM-NO) of 3rd. latch switch must be closed. After that
the contacts (COM-NO)  of the secondary interlock switch
and the door sensing switch are made closed.

7-3. When the oven door is opened and the contacts (COM-

NO) of  the secondary interlock switch remain closed, the
fuse F10A will blow. Because the relay RY2 and monitor
switch are closed  and a short circuit is caused.

When the microwave oven is preset for variable cooking power,
the line voltage 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.

Press the MANUAL/REPEAT key. Program desired convection
temperature by touching the OVEN(˚C) key. When the START
key is touched, the following operations occur: (Figure O-3)
1. The coil of shut-off relays (RY1, RY3 and RY5) are energized,

the oven lamp, cooling fan motor, turntable motor and jet
motor are turned on. The contacts (COM-NO) of relay RY6
are opened.

2.  The solid-state relays are energized by the control unit and

the main supply voltage is applied to the top and side heating
elements.

32 sec. ON

100%

30sec. ON

90%

26 sec. ON

80%

24 sec. ON

 70%

22 sec. ON

60%

18 sec. ON

50%

16 sec. ON

40%

12 sec. ON

30%

8 sec. ON

20%

6 sec. ON

10%

0 sec. ON

0%