Sharp R210Am-008 Schematic

R

SERVICE MANUAL

COOKING CONTROL

WITH COOK & DEFROST GUIDE

MED

MED LOW

LOW

25

30

COOK & DEFROST
GUIDE (KG)

2.0

1.5

20

MED HIGH

HIGH

TIMER

0

5

0.5

10

1.0

15

MICROWAVE OVEN

S3768R210AM//

800W

E

MODEL

R-210AM

In the interests of user-safety the oven should be restored
to its original condition and only parts identical to those
specified should be used.

TABLE OF CONTENTS

Page

SERVICING....................................................................................................................................... 2

CAUTION, MICROWAVE RADIATION ............................................................................................. 3

WARNING......................................................................................................................................... 3

PRODUCT DESCRIPTION ............................................................................................................... 3

OPERATION DATA........................................................................................................................... 4

DOOR SWITCHES............................................................................................................................ 4

OUTPUT POWER TEST PROCEDURE ........................................................................................... 5

COMPONENT REPLACEMENT ....................................................................................................... 5

SCHEMATIC DIAGRAM ................................................................................................................... 7

WIRING DIAGRAM ........................................................................................................................... 8

PARTS LIST...................................................................................................................................... 9

EXPLODED ILLUSTRATION ............................................................................................................ 11

NEW FEATURE ................................................................................................................................ 14

SHARP CORPORATION

210AM - 1

SERVICING

WARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with following parts
will result in electrocution:­High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier, High voltage harness.

REMEMBER TO CHECK 3D

1) Disconnect the supply.

2) Door opened, and wedged open.

3) Discharge high voltage capacitor.

WARNING AGAINST THE CHARGE OF THE HIGH-VOLTAGE CAPACITOR
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, of the connecting lead of the
high-voltage rectifier) against the chassis using a screwdriver with an insulated handle.

Sharp recommend that wherever possible, fault-finding is carried out with the supply disconnected. In some
cases, it 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:-

• Carry out 3D checks (see above).

• Disconnect the supply leads from the high voltage transformer, making a note of the polarity. Insulate the
connectors, ensuring they are positioned away from the transformer and fastened there.

• Connect any relevant test equipment e.g. voltmeter.

• Reconnect the oven to the supply, then close the door.

• Note the results of the test, taking care to keep clear of the operational oven.

• Carry out 3D checks (see above).

• Reconnect the leads to the transformer. Take care to observe correct polarity.

• Carry out 4R checks (see below).

Microwave ovens should not be used without a load. 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 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.

AFTER REPAIR REMEMBER TO CHECK 4R

1) Reconnect all leads removed from components during testing.

2) Replace the outer case (cabinet).

3) Reconnect the supply.

4) Run the oven. Check all functions.

When all service work is completed, and the oven is fully assembled, the microwave power output should be checked
and microwave leakage test carried out.

IMPORTANT: If the oven becomes inoperative because of a blown fuse F8A in the 1st latch switch - monitor switch

circuit, check the 1st latch switch and monitor switch before replacing the fuse F8A.

210AM - 2

CAUTION / WARNING

CAUTION

MICROWAVE RADIATION

Do not become exposed to radiation from the
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 ener­gized.

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

The parts marked '*' on the parts list and schematic
diagram have voltages in excess of 250V.

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

All the parts marked "∆" on the parts list may cause
undue microwave exposure, by themselves, or when
they are damaged, loosened or removed.

WARNING

WARNING

THIS APPLIANCE MUST BE EARTHED. THE WIRES IN THIS MAINS LEAD ARE COLOURED IN

ACCORDANCE WITH THE FOLLOWING CODE:
GREEN-AND-YELLOW : EARTH BLUE : NEUTRAL BROWN : LIVE

If the mains lead is replaced, only part number QACCBA030WREO should be used

PRODUCT DESCRIPTION

SPECIFICATION

Power Requirements 230 /240 Volts 50 Hertz Single phase, 3 wire grounded
Power Consumption 1.3KW
Power Output 800 watts nominal of RF microwave energy (measured by way of IEC 705)

Operating frequency of 2450 MHz
Case Dimensions Width 449 mm Height 282 mm including foot Depth 369 mm
Cooking Cavity Dimensions Width 290 mm Height 194 mm Depth 313 mm
Turntable diameter 272 mm
Control Complement Mechanical Control System

Microwave Power for Variable Cooking

Repetition Rate :

HIGH..................... Full power throughout the cooking time

MEDIUM HIGH .....approx. 70% of Full Power

MEDIUM ...............approx. 50% of Full Power

MEDIUM LOW......approx. 30% of Full Power

LOW ..................... approx. 10% of Full Power

Set Weight Approx. 13.3 kg

210AM - 3

OPERATING SEQUENCE

OFF CONDITION

Closing the door activates all door interlock switches (moni­tored latch switch and latch switch).

IMPORTANT
When the timer knob is at "0" the oven is in the OFF
condition.

HIGH, MEDIUM HIGH, MEDIUM, MEDIUM
LOW, LOW COOKING

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

26 sec. ON

HIGH

20 sec. ON

MEDIUM HIGH

14 sec. ON

MEDIUM

8 sec. ON

MEDIUM LOW

4 sec. ON

LOW

6 sec. OFF

12 sec. OFF

18 sec. OFF

22 sec. OFF

NOTE: The ON/OFF time ratio does not exactly correspond

to the percentage of microwave power, because
approx. 3 seconds are needed for heating up the
magnetron filament.

Approx. 100% = 800 Watts

Approx. 70% = 560 Watts

Approx. 50% = 400 Watts

Approx. 30% = 240 Watts

Approx. 10% = 80 Watts

DOOR SWITCHES

DOOR OPEN MECHANISM

LATCH HOOK

DOOR

LATCH
HEADS

DOOR OPEN BUTTON

SW1: MONITORED
LATCH SWITCH

SW3: MONITOR
SWITCH

SW2: LATCH
SWITCH

OPEN LEVER

MONITORED LATCH SWITCH (SW1)
STOP SWITCH (SW3)

1. When the oven door is closed, the contacts (COM - NO)
must be closed.

2. When the oven door is opened, the contacts (COM ­NO) must be opened.

MONITOR SWITCH (SW2)

1. When the oven door is closed, the contacts (COM - NC)
must be opened.

2. When the oven door is opened, the contacts (COM ­NC) must be closed.

3. If the oven door is opened and the contacts (COM - NO)
of the monitored latch switch (SW1) fail to open, the fuse
F8A blows simultaneously with closing the contacts
(COM - NC) of the monitor switch (SW2).

CAUTION: BEFORE REPLACING A BLOWN FUSE (F)

F8A TEST THE MONITORED LATCH SWITCH
(SW1), + MONITOR SWITCH (SW3) FOR
PROPER OPERATION.

Figure D-1. Door Open Mechanism

210AM - 4

OUTPUT POWER TEST PROCEDURE

MICROWAVE OUTPUT POWER (IEC-705)
The power output of this oven is rated using the method specified by IEC-705. Full details of how to carry out this

procedure can be found in the Sharp Technical Training notes which is available from Sharp Parts Centre
(part number SERV-LITMW01).

Using this procedure, the heating time to raise 1000g of water by 10°C is approximately 50 seconds.
The IEC-705 procedure must be carried out using laboratory-type procedures and equipment. These requirements

make the procedure unsuitable for routing performance checks. An indication of the power being produced by the oven
can however be obtained using the procedure given below.

Alternative simplified method:

1. Place 2 litres of cold water (between 12°C and 20°C) in a suitable container.

2. Stir the water and measure the temperature in °C. Note temperature as T1.

3. Place the container in the microwave and heat the water for 2 minutes on full power.

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:
R.F. Power Output = (T2 - T1) x 70.

Note: The result from this test should be within 10% of the power rating stated on the rating label.

MICROWAVE LEAKAGE TEST
This oven should be tested for microwave leakage on completion of any repair or adjustment, following the procedure

described in the Sharp Technical Training notes (part number SERV-LITMW01). The maximum leakage permitted in
BS EN 60335-2-25 is 50W/m

2

(equivalent to 5mW/cm2), however it is not normal to detect any significant leakage,

therefore, any leakage which is detected should be investigated.
It is essential that only leakage detectors with current calibration traceable to the National Physical Laboratories are used.
Suitable leakage detectors : CELTEC A100

APOLLO X1

COMPONENT REPLACEMENT

MONITORED LATCH SWITCH, LATCH
SWITCH, AND MONITOR SWITCH REMOVAL

1. CARRY OUT 3D CHECKS.

2. Disconnect the leads from all switches.

3. Remove the one (1) screw holding the latch hook to the
oven cavity.

4. Remove the latch hook.

5. Push the retaining tab slightly and remove the switch.

Post

LATCH HOOK

Post

SW1: MONITORED
LATCH SWITCH

Tab

SW3: MONITOR
SWITCH

210AM - 5

Tab

Post

SW2: LATCH
SWITCH

Tab

Figure C-4. Switches