Sharp R-211(W)M - User Manual

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211M -

S1892R211M///

SHARP CORPORATION

SERVICE MANUAL

TABLE OF CONTENTS

Page

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

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

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

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

OPERATING SEQUENCE ................................................................................................................ 4

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

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

TEST PROCEDURES....................................................................................................................... 6

DIGITAL ANALOGUE CONTROL PANEL ASSEMBLY ................................................................... 8

COMPONENT REPLACEMENT....................................................................................................... 12

SCHEMATIC DIAGRAM ................................................................................................................... 13

WIRING DIAGRAM ........................................................................................................................... 14

PARTS LIST...................................................................................................................................... 17

EXPLODED ILLUSTRATION ............................................................................................................ 20

MICROWAVE OVEN

MODEL

R-211(W)/(BL)M

R-211(G)M

R-211(B)M

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.

R-211

ILLUMINATED

TIMER

COOKING CONTROL

WITH COOK & DEFROST GUIDE

0.7

1.0

(KG)

2.0

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This document is a service manual for the SHARP R-211 series of microwave ovens, including models R-211(W)/(BL)M, R-211(G)M, and R-211(B)M. It provides comprehensive information for servicing, maintenance, and understanding the operation of these appliances.

Function Description

The SHARP R-211 series are microwave ovens designed for variable cooking power. They operate by supplying line voltage to a power transformer intermittently within a 26-second time base, controlled by a relay. This allows for different levels of microwave power output, ranging from high to low, to suit various cooking needs. The oven features a digital analogue control panel for setting cooking parameters and includes safety mechanisms such as door interlock switches.

Important Technical Specifications

Power Requirements:

230-240 Volts, 50 Hertz, Single phase, 3 wire grounded.

Power Consumption:

1.24 kW.

Power Output:

800 watts nominal of RF microwave energy (measured by way of IEC 705).
Operating frequency: 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:

DIGI/ANA (Digital Analogue).

Microwave Power for Variable Cooking (Repetition Rate):

HIGH: Full power throughout the cooking time (26 sec. ON).
MEDIUM HIGH: Approx. 70% of Full Power (20 sec. ON, 6 sec. OFF).
MEDIUM: Approx. 50% of Full Power (14 sec. ON, 12 sec. OFF).
MEDIUM LOW: Approx. 30% of Full Power (8 sec. ON, 18 sec. OFF).
LOW: Approx. 10% of Full Power (4 sec. ON, 22 sec. OFF).
Note: The ON/OFF time ratio does not exactly correspond to the percentage of microwave power, because approximately 3 seconds are needed for heating up the magnetron filament.

Set Weight:

Approx. 13.3 kg.

Usage Features

The R-211 series microwave ovens offer a range of power settings for flexible cooking. The digital analogue control panel allows users to select desired power levels and cooking times. The door mechanism incorporates multiple switches (Monitored Latch Switch SW1, Monitor Switch SW2, Stop Switch SW3) to ensure safe operation. The oven requires a load (e.g., a cup of cold water) when testing for microwave energy presence.

Maintenance Features

The manual emphasizes user safety and proper servicing procedures. Safety Precautions:

High Voltage: Microwave ovens contain high voltage and current circuitry (High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier, High voltage harness). Contact with these parts can result in electrocution.
Capacitor Discharge: The high-voltage capacitor remains charged for about 60 seconds after the oven is switched off. It must be short-circuited against the chassis with an insulated screwdriver before servicing.
3D Checks (Disconnect, Door Open, Discharge): Essential before any repair.
4R Checks (Reconnect, Replace Case, Reconnect Supply, Run Oven): Essential after any repair.
Microwave Radiation: Avoid exposure to radiation from the magnetron or other parts conducting microwave energy. Ensure all microwave connections, waveguides, flanges, and gaskets are secured. Never operate without an energy-absorbing load or look into an open waveguide when energized.
Earthing: The appliance must be earthed. Mains lead wires are coloured GREEN-AND-YELLOW (Earth), BLUE (Neutral), and BROWN (Live). Only specified replacement parts should be used for the mains lead.
Fuse F8A: If this fuse blows, check the 1st latch switch and monitor switch before replacing F1.

Servicing Procedures:

Fault Finding: Sharp recommends fault-finding with the supply disconnected. If the supply must be connected for control circuitry investigation, the high voltage circuit should be disabled.
Microwave Output Power Test (IEC-705): A detailed procedure for measuring power output, with a simplified alternative method provided for routine checks. The output power should be within 10% of the rating label.
Microwave Leakage Test: Must be performed after any repair or adjustment using calibrated leakage detectors. The maximum permitted leakage is 50W/m².
Component Test:
- Control Panel Assembly Test: Symptoms of a defective control unit include LED issues (not lighting, low brightness, flickering, always on), buzzer issues, or inability to set cooking parameters.
- Relay Test: Check voltage at the relay coil during cooking operation. Defective relays or control units can be identified.
- PWB Foil Pattern Repair: If the fine foil pattern on the Printed Wiring Board (PWB) is open (acting as a fuse), a troubleshooting guide is provided for repair, including checking the supply voltage, low voltage transformer, and inserting jumper wires or coils.
Digital Analogue Control Panel: Consists of LSI, power source, synchronizing signal, ACL, buzzer, encoder, indicator, and potentiometer circuits. Detailed pin descriptions for the LSI (M34225M1) are provided, outlining signals for magnetron driving, oven lamp/motor control, door sensing, and buzzer.
Handling Electronic Components: CMOS LSI parts are sensitive to static electricity and high voltage. Precautions include wrapping in aluminium foil, grounding the technician and soldering iron, and careful handling.
Door Replacement: Involves removing the choke cover, lifting the door assembly, and ensuring proper alignment upon re-installation. A microwave survey meter must be used after door service.
Inner/Outer Door Film Replacement: Procedures for removing and installing the door film.
Latch Head Removal: Procedure for removing the latch head.
Monitored Latch Switch, Latch Switch, and Monitor Switch Removal: Procedures for disconnecting leads, removing screws, and detaching switches.