R-90GCK (serv.man17). Complete - Sharp Home Appliance Service Manual (repair manual)

47

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

Page

SERVICING ................................................................................................................. INSIDE FRONT COVER
CAUTION, MICROWAVE RADIATION .............................................................................................................  1
WARNING .......................................................................................................................................................... 1
PRODUCT SPECIFICATIONS .........................................................................................................................  2
GENERAL INFORMATION ................................................................................................................................ 2
APPEARANCE VIEW .......................................................................................................................................  3
OPERATION SEQUENCE ................................................................................................................................  4
FUNCTION OF IMPORTANT COMPONENTS ................................................................................................. 7
TROUBLESHOOTING GUIDE .........................................................................................................................  9
TEST PROCEDURE .......................................................................................................................................  11
CONTROL UNIT ASSEMBLYL ........................................................................................................................ 19
PRECAUTIONS FOR USING LEAD-FREE SOLDER ..................................................................................... 23
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ...........................................................  24
MICROWAVE MEASUREMENT ....................................................................................................................  31
WIRING DIAGRAM .........................................................................................................................................  32
PICTORIAL DIAGRAM ...................................................................................................................................  35
POWER UNITL CIRCUIT ................................................................................................................................ 36
CPU UNITL CIRCUIT ...................................................................................................................................... 37
GRID ASSIGNMENT OF FLUORESENT DISPLAY TUBE ............................................................................. 38
PRINTED WIRING BOARD ............................................................................................................................. 39
PARTS LIST ...................................................................................................................................................  40

48

1) Disconnect the supply.
2) Door opened, and wedged open.
3) To discharge the high voltage capacitor, wait for 60

seconds.

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 with the use of an insulated
screwdriver.

Sharp recommend that wherever possible fault-finding
is carried out with the supply disconnected. It may, in
some cases, be necessary to connect the supply after
the outer case has been removed, in this event carry
out 3D checks and then disconnect the leads to the
primary of the power transformer. Ensure that these
leads remain isolated from other components and the
oven chassis. (Use insulation tape if necessary.) When
the testing is completed carry out 3D checks and
reconnect the leads to the primary of the power trans-
former.

1) Reconnect all leads removed from components

during testing.

2) Replace the outer case (cabinet) and back plate.
3) Reconnect the supply.
4) Run the oven. Check all functions.

 Microwave ovens should not be run empty. 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 power level to HIGH. And set  the
microwave timer for two (2) minutes. When the two
minutes has elapsed (timer at zero) carefully check
that the water is now hot. If the water remains cold carry
out 3D checks and re-examine the connections to the
component being tested.

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

Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts
of the high voltage circuit will result in electrocution. High voltage capacitor, High voltage transformer, Magnetron,
High voltage rectifier assembly, High voltage fuse, High voltage harness.

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

Grill cooking

2.7 kW Approx. 11.3 A

Convection cooking

2.7 kW Approx. 11.3 A

DUAL 1 cooking

2.8 kW Approx. 11.7 A

DUAL 2 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 405 mm (including foot)

Depth 625 mm

Cooking Cavity Dimensions

Width  408 mm

Height 230 mm

Depth 345 mm

Turntable diameter

330 mm

Control Complement

Touch Control System

Clock (1:00 - 12:59) / Timer (0 - 99 minutes 90 sec.)

Microwave Power for Variable Cooking

 Repetition Rate;

100 % (HIGH) .......................... Full power throughout the cooking time

70 % (MEDIUM HIGH) ........................... approx. 70% of FULL Power
50 % (MEDIUM) ..................................... approx. 50% of FULL Power
30 % (MEDIUM LOW) ............................ approx. 30% of FULL Power
10 % (LOW) ............................................ approx. 10% of FULL Power

Convection temperature control range:

   250˚C, 230˚C, 220˚C, 200˚C, 180˚C, 160˚C, 130˚C, 100˚C, 70˚C and 40˚C

AUTO COOK key, LESS/MORE keys, WEIGHT keys
AUTO DEFROST key, BASIC COOK key, RECIPES key
MENU keys, TIME keys, CLOCK SET key, STOP/CLEAR key
DUAL MODE keys, GRILL key, CONV.(

°

C) key, POWER LEVEL key

INFO key, KITCHEN TIMER key, START/AUTO MINUTE key

Set Weight

Approx. 39 kg