Sharp R-895(AL)M User manual

R-895M - 1
TABLE OF CONTENTS
Page
CAUTION, MICROWAVE RADIATION.................................................................................................... 2
WARNING................................................................................................................................................. 2
SERVICING ............................................................................................................................................. 3
PRODUCT SPECIFICATIONS ................................................................................................................. 4
GENERAL INFORMATION....................................................................................................................... 4
APPEARANCE VIEW .............................................................................................................................. 5
OPERATION SEQUENCE........................................................................................................................ 6
FUNCTION OF IMPORTANT COMPONENTS ....................................................................................... 9
TROUBLESHOOTING GUIDE ............................................................................................................... 12
TEST PROCEDURES ........................................................................................................................... 13
TOUCH CONTROL PANEL ASSEMBLY .............................................................................................. 19
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE .................................................. 24
MICROWAVE MEASUREMENT ........................................................................................................... 30
SCHEMATIC DIAGRAMS...................................................................................................................... 31
PICTORIAL DIAGRAM .......................................................................................................................... 35
POWER UNIT CIRCUIT DIAGRAM........................................................................................................ 36
CPU UNIT CIRCUIT DIAGRAM.............................................................................................................. 37
PRINTED WIRING BOARD OF POWER UNIT DIAGRAM .................................................................... 38
PARTS LIST .......................................................................................................................................... 39
EXPLODED DIAGRAM OF OVEN PARTS ........................................................................................... 41
CONTROL PANEL & DOOR PARTS .....................................................................................................42
MISCELLANEOUS/PACKING & ACCESSORIES .................................................................................. 43
S70224R895M//
MICROWAVE OVEN WITH
GRILL AND CONVECTION
MODEL R-895(AL)M
In interests of user-safety the oven should be restored to its original
condition and only parts identical to those specified should be used.
SERVICE MANUAL
SHARP CORPORATION
®

R-895M - 41
OVEN PARTS
7-6
7-18
7-11
7-16
7-8
7-18
7-7
x7
x2
1-18
4-25
4-14
4-26
4-30
4-32
4-27
4-32
4-19
7-12
7-13
7-9
4-3
1-8
4-21
4-24
7-18
7-18
7-18
7-18
4-28
7-4
2-3
7-4
7-15
7-15
4-18
7-18
7-17
7-7
4-1
4-5
1-11
7-18
4-18
4-6
4-4
7-18
1-1 7-7
7-6
1-3
7-6
7-18
6-5
1-3
7-6
1-2
1-20
1-16
1-14
1-15
7-17
7-18
7-18
7-10
7-17
4-7
7-6
6-3
6-5
7-14
7-1
1-10 4-16
1-7
1-17
4-13
4-12
1-4
7-6
7-19
4-29
4-20
7-18
7-18
2-4
2-5
2-5
4-9
4-31
7-3
1-19
4-2
4-15
7-5 7-2
7-2
1-21
7-5
4-10
4-22
4-17
4-11
4-8
6-4
4-23
1-9
1-6
1-5
1-12
6-6
2-2
2-1
1-13
7-5
NOTE: In the event of removing the turn-
table motor cover this part should
be refitted using screw connec-
tion: LX-EZA045WRE0 (7-20)
OVEN PARTS

R-895M - 42
CONTROL PANEL PARTS
DOOR PARTS
CONTROL PANEL AND DOOR PARTS
3-4
3-2 3-7
3-7
3-7
3-5
3-6
3-1
3-3
5-4
5-6
5-7
5-8
5-3
5-12
5-11
5-1
5-9
5-9
5-10
5-2
5-5
5-10

R-895M - 43
'2002 SHARP CORP. Printed in U.K.
PACKING AND ACCESSORIES
®
TURNTABLE TRAY
PRINTED MATTER
ACCESSORY HOLDER
(SPADPA015URE1)
TOP PAD ASSEMBLY
(FPADBA018URK0)
BOTTOM PAD ASSEMBLY
(FPADBA019URK0)
WRAP COVER
(SPADFA353WRE0)
DOOR PROTECTION SHEET

(SPADPA026URE0)
PACKING CASE
SPAKCA437URR0
Not Replaceable Items.
PROTECTION SHEET
(SPADPA024URE0)
BOX MODEL LABEL
TLAB-A310URR0
INTO THE
OVEN CAVITY
LOW RACK
HIGH RACK
COPYRIGHT © 2002 BY SHARP CORPORATION
ALL RIGHTS RESERVED.
No part of this publication may be reproduced,
stored in retrieval systems, or transmitted in any
form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without
prior written permission of the publisher.
MISCELLANEOUS
Actual wire harness may be different than illustration.
6-5
6-1
6-8
6-2
6-7
MISCELLANEOUS / PACKING & ACCESSORIES

R-895M - 39
Note: The parts marked "∆" may cause undue microwave exposure. / The parts marked "*" are used in
voltage more than 250V. / "§" Mark: Spare parts delivery section
REF. NO. PART NO. § DESCRIPTION Q'TY CODE
PARTS LIST
*
*
*
∆*
ELECTRIC PARTS
1- 1 FH-HZA075WRE0 U Thermistor 1 AN
1- 2 RTRN-A529WRE0 U TC transformer 1 AV
1- 3 QACCBA004URE3 U Power supply cord 1 AT
1- 4 FH-DZA035WRE0 U High voltage rectifier assembly 1 AP
1- 5 FPWBFA309WRE2 U Noise filter 1 AT
1- 6 QFS-CA025WRE0 U Fuse F8A 1 AC
1- 7 QFS-BA009WRE0 U Fuse 20A 1 AC
1- 8 RMOTEA373WRE0 U Convection motor 1 AV
1- 9 RC-QZA240WRE0 U High voltage capacitor 1 AR
1-10 RTHM-A098WRE0 U Thermal cut-out 125˚C off(MG) 1 AH
1-11 RTHM-A124WRZZ U Thermal cut-out 145˚C off 115˚C on (OVEN) 1 AH
1-12 RHET-A255WRZZ U Top grill heating element 1 AT
1-13 RHET-A248WRZ1 U Bottom grill heating element 1 AW
1-14 QSW-MA146WRZZ J Monitored latch switch 1 AC
1-15 QSW-MA147WRZZ J Stop switch 1 AG
1-16 QSW-MA146WRZZ J Monitor switch 1 AC
1-17 RMOTEA002URE1 U Fan motor 1 AW
1-18 RLMPTA066WRE0 U Oven lamp 1 AK
1-19 RTRN-A019URE0 U High voltage transformer 1 BF
1-20 RV-MZA243WRE1 U Magnetron 1 BH
1-21 RMOTDA227WRE0 U Turntable motor 1 AU
CABINET PARTS
2- 1 GCABDA001URP2 U Back plate 1 AQ
2- 2 GCABDA002URP0 U Sub back plate 1 AH
2- 3 GCABUW045URP0 U Outer case cabinet 1 AW
2- 4 GDAI-A002URP0 U Base plate 1 AR
2- 5 GLEGPA057WRE1 U Foot 2 AB
CONTROL PANEL PARTS
3- 1 DPWBFA184URK0 U Power unit 1 BC
3- 1A QCNCMA453DRE0 U 5-pin connector (CN-A) 1 AC
3- 1B QCNCMA414DRE0 U 2-pin connector (CN-B) 1 AB
3- 1C QCNCMA410DRE0 U 2-pin connector (CN-C) 1 AB
3- 1D QCNCMA230DRE0 U 4-pin connector (CN-E) 1 AC
3- 1E FW-VZA266DREZ U 15pin wire harness (WH-1) 1 AH
C1 RC-KZA087DRE0 U Capacitor 0.1 uF 50V 1 AB
C2 VCEAG31VW108M U Capacitor 1000 uF 35V 1 AE
C3 RC-KZA087DRE0 U Capacitor 0.1 uF 50V 1 AB
C4-5 VCEAG31VW106M U Capacitor 10 uF 35V 2 AB
D1-7 VHD1SS270A/-1 U Diode (1SS270A) 7 AA
D11-14 VHD1N4005E/-2 U Diode (1N4005E) 4 AA
D11-14 VHD1N4004S/-1T U Diode (1N4004S) (Interchangeable) 4 AA
Q2 VSKTA1274//-3 U Transistor (KTA1274) 1 AA
Q3 VSKRC243M//-3 U Transistor (KRC243M) 1 AB
R2 VRD-B12EF152J U Resistor 1.5K ohm 1/4W 1 AA
R3-4 VRS-B13AA511J U Resistor 510 ohm 1W 2 AB
R5 VRD-B12EF332J U Resistor 3.3K ohm 1/4W 1 AA
R6 VRS-B13AA201J U Resistor 200 ohm 1W 1 AB
RY1 RRLY-A117DRE0 U Relay (DU18D1-1P(M)-R) 1 AG
RY2 RRLY-A122DRE0 U Relay (DU18D1-1P(M)-R-S) 1 AG
RY3-4 RRLY-A113DRE0 U Relay (DU24D1-1P(M)-R) 2 AG
RY5-7 RRLY-B004MRE0 U Relay (FTR-F3AA024E) 3 AL
SP1 RALM-A014DRE0 U Buzzer (PKM22EPT) 1 AG
VRS1 RH-VZA034DRE0 U Varistor (10G471K) 1 AD
ZD2 VHEHZ201///-1 U Zener diode (HZ20-1) 1 AB
3- 2 DPWBFC239WRKZ U CPU unit 1 BC
3- 3 FUNTKC135URE0 U Key unit 1 AS
3- 4 HPNLCA123URR0 U Control panel frame 1 AV
3- 5 LHLD-A007URF1 U LCD holder 1 AD
3- 6 PSHEPA647WRE0 U LCD sheet 1 AL
3- 7 XEPSD30P10XS0 U Screw : 3mm x 10mm 6 AA
OVEN PARTS
4- 1 DOVN-A023URK0 U Oven cavity 1 BG
4- 2 LBNDKA107WRP1 U Capacitor holder 1 AD
4- 3 FDUC-A003URY0 U Air duct assembly 1 AL
4- 4 LANGQA005URP0 U Air separate angle B 1 AC
4- 5 PDUC-A636WRP1 U Air guide duct 1 AM
4- 6 PFILWA001URP0 U Lamp filter 1 AB
4- 7 PHOK-A002URF1 U Latch hook 1 AH
4- 8 LANGQA014URP0 U Turntable motor angle 1 AE
4- 9 PCUSUA019URE0 U Cushion 1 AA
4-10 FANGTA003URY0 U Turntable motor shaft assembly 1 AL
4-11 PPACGA002URE0 U Seal packing 1 AB
4-12 NFANJA038WRE0 U Fan blade 1 AF
∆
∆

R-895M - 40
*
∆
∆
∆
REF. NO. PART NO. § DESCRIPTION Q'TY CODE
Note: The parts marked "∆" may cause undue microwave exposure. / The parts marked "*" are used in
voltage more than 250V. / "§" Mark: Spare parts delivery section
PARTS LIST
HOW TO ORDER REPLACEMENT PARTS
To have your order filled promptly and correctly, please furnish the following information.
1. MODEL NUMBER 2. REF. NO.
3. PART NO. 4. DESCRIPTION
4-13 PDUC-A637WRF2 U Fan duct 1 AL
4-14 NFANMA002URP0 U Cooling fan 1 AF
4-15 GCOVHA001URP1 U Bottom heater cover 1 AM
4-16 LANGFA155WRP7 U Chassis support 1 AF
4-17 PPACGA001URE0 U Heater packing 1 AD
4-18 LANGQA008URP0 U Grill heater angle 2 AD
4-19 NFANMA001URP0 U Convection fan 1 AD
4-20 PSPAGA001WRE0 U Vibration proof cushion 1 AA
4-21 PCUSUA006URE0 U Air cushion B 1 AA
4-22 PCOVQA002URP0 U Heater cover 1 AD
4-23 PCOVPA308WRE1 U Waveguide cover 1 AE
4-24 PCUSUA015URE0 U Back plate cushion 1 AB
4-25 PPIP-A001UR10 U Pipe 1 AE
4-26 PCOVQA001URP0 U Rear heat cover 1 AP
4-27 PDUC-A606WRF1 U Air intake duct 1 AK
4-28 PDUC-A008URP0 U Exhaust duct 1 AK
4-29 PSKR-A308WRF0 U Rear barrier 1 AH
4-30 PDUC-A003URP0 U Convection duct 1 AL
4-31 PCUSUA012URE0 U Air defect cushion 1 AB
4-32 LANGQA004URP0 U Convection air angle 2 AN
DOOR PARTS
5- 1 DDORFA766WRK0 U Door panel assembly 1 BE
5- 2 GWAKPA103URR0 U Door frame 1 AU
5- 3 LSTPPA017URF0 U Latch head 1 AG
5- 4 LHLD-A012URF0 U Glass holder 1 AB
5- 5 MSPRTA197WREZ U Latch spring 1 AC
5- 6 PGLSPA027URE0 U Front door glass 1 AN
5- 7 JHNDPA012URT0 U Door handle A 1 AK
5- 8 JHNDPA013URT0 U Door handle B 1 AR
5- 9 XETSD40P30000 U Screw : 4mm x 30mm 2 AA
5-10 XEBSD30P08000 U Screw : 3mm x 8mm 3 AA
5-11 XEBSD30P06000 U Screw : 3mm x 6mm 4 AA
5-12 GCOVHA365WRF3 U Choke cover 1 AM
MISCELLANEOUS
6- 1 FAMI-A072WRK2 U High rack 1 AT
6- 2 FAMI-A095WRK1 U Low rack 1 AR
6- 3 LHLDKA008WRF1 U P-clip 1 AA
6- 4 CTNT-A005URK0 U Turntable tray 1 AY
6- 5 FW-VZA061URE1 U Stop switch harness 1 AE
6- 6 TCAUHA001WRR1 U Caution label 1 AC
6- 7 QW-QZA210WRE1 U High voltage wire B 1 AD
6- 8 FW-VZA098URE0 U Main harness 1 AX
6- 9 TINS-A286URR0 U Quick start guide 1 AD
6-10 TINS-A285URR0 U Operation manual 1 AS
SCREWS,NUTS AND WASHERS
7- 1 XHPSD40P08K00 U Screw: 4mm x 8mm 1 AA
7- 2 LX-NZ0061WRE0 J M4 Flange nut 4 AA
7- 3 XWWSD50-06000 J Washer: 5mm x 0.6mm 1 AA
7- 4 XOTSE40P10000 J Screw: 4mm x 10mm 4 AA
7- 5 XHPSD40P06000 J Screw: 4mm x 6mm 3 AA
7- 6 XHTSD40P08RV0 J Screw: 4mm x 8mm 6 AA
7- 7 XOTWW40P06000 J Screw: 4mm x 6mm 10 AA
7- 8 XBTSD40P05000 U Screw: 4mm x 5mm 2 AA
7- 9 XNEUW40-32000 J Nut: 4mm x 3.2mm 1 AA
7-10 XOTSD40P12RV0 J Screw: 4mm x 12mm 2 AA
7-11 XRESE40-06000 U Ring 1 AA
7-12 XWHUW40-08000 U Washer: 4mm x 0.8mm 1 AA
7-13 XWSUW40-10000 U Washer: 4mm x 1.0mm 1 AA
7-14 XEPSD40P25000 J Screw: 4mm x 25mm 2 AA
7-15 XBPWW30P05K00 J Screw: 3mm x 5mm 2 AA
7-16 XWHUW50-08000 J Washer: 5mm x 0.8mm 1 AA
7-17 XEBSD30P06000 U Screw: 3mm x 6mm 3 AA
7-18 LX-CZA001URE0 U Special screw 24 AA
7-19 XFPSD50P10KS0 U Screw: 5mm x 10mm 2 AB
7-20 LX-EZA045WRE0 J Special screw (TTM cover mounting screw) 1 AA

R-895M - 2
SERVICE MANUAL
MICROWAVE OVEN WITH
GRILL AND CONVECTION
R-895(AL)M
GENERAL IMPORTANT INFORMATION
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.
WARNING
Never operate the oven until the following points are ensured.
(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.
Never operate the Grill and/ or Bottom heater with the oven
outer cabinet removed. (Because air flow is eliminated, and the
excess heat generated on adjacent components). It can cause
permanent damage or a fire.
SHARP CORPORATION
OSAKA, JAPAN
WARNING
MICROWAVE RADIATION
Personnel 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.
®

R-895M - 3
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 sec-
onds 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 High voltage
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 High
voltage transformer.
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 assembly, High voltage harness.
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.
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 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 compo-
nent being tested.
When all service work is completed, and the oven is fully
assembled, the microwave power output should be checked and
a microwave leakage test should be carried out.

R-895M - 4
PRODUCT DESCRIPTION
SPECIFICATION
ITEM DESCRIPTION
Power Requirements 230 - 240 Volts / 50 Hertz / Single phase, 3 wire earthed
Power Consumption Microwave cooking 1.50 kW Approx. 6.5 A
Convection cooking 1.91 kW Approx. 8.0 A
Top Grill mode ...................... 1.25 kW Approx. 5.2 A
Grill cooking Bottom Grill mode ................. 0.70 kW Approx. 2.9 A
Top and Bottom mode ......... 1.90 kW Approx. 7.9 A
Micro and Top Grill ............... 2.70 kW Approx. 11.5 A
Dual cooking Micro and Bottom Grill .......... 2.15 kW Approx. 9.2 A
Micro and Convection ........... 2.16 kW Approx. 9.3 A
Power Output 900 W nominal of RF microwave energy (measured by method of IEC 60705)
Operating fequency 2450 MHz
Top Grill heating element Power Output 1200 W
Bottom heating element Power Output 650 W
Case Dimensions Width 520 mm Height 309 mm (including foot) Depth 482 mm
Cooking Cavity Dimensions Width 353 mm Height 207 mm Depth 357 mm
Turntable diameter 325 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
TIME keys, BREAKFAST key, PIZZA key, EXPRESS COOK keys
EXPRESS DEFROST keys, MEAL IN ONE keys
POWER LEVEL key, GRILL key, DUAL CONV./GRILL key
CONV. (˚C) key, LESS/MORE keys, WEIGHT keys
INFO key, STOP/CLEAR key, START/AUTO MINUTE key
KITCHEN TIMER/CLOCK SET key
Net Weight Approx. 19 kg
GENERAL INFORMATION
WARNING
THIS APPLIANCE MUST BE EARTHED
IMPORTANT
THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:
GREEN-AND-YELLOW : EARTH
BLUE : NEUTRAL
BROWN : LIVE
As part of our policy of continuous improvement, we reserve the right to
alter design and specifications without notice

R-895M - 5
APPEARANCE VIEW
OVEN
1. Control panel
2. Oven lamp
3. Waveguide cover
4. Bottom grill heating ele-
ment (Bottom Grill)
5. Turntable motor shaft
6. Oven cavity
7. Door seals and sealing
surfaces
8. Door latches
9. Door opening handle
10.Top grill heating element
(Top Grill)
11.Ventilation openings
12.Outer cabinet
13.Powercord
14.Turntable tray
15.High rack
16.Low rack
CONTROL PANEL
14
1
2
9
3678 5 4
10 11
13
12
16 15
KG
COOK
DEFROST AUTO
%
nfo
AUTO indicator
DEFROST indicator
TOP GRILL indicator.
BOTTOM GRILL indicator
CONVECTION indicator.
COOK indicator
MICROWAVE indicator.
WEIGHT indicators.
LESS/MORE indicators.
DIGITAL DISPLAY
INFO indicator
MICROWAVE POWER 
LEVEL indicator.
DIGITAL DISPLAY
TIME keys
PIZZA key
EXPRESS COOK keys
EXPRESS DEFROST keys
MEAL IN ONE keys
LESS/MORE keys
INFO key
START AUTO MINUTE key
DUAL CONV./GRILL key
CONV. (˚C) key
BREAKFAST key
POWER LEVEL key
WEIGHT keys
KITCHEN TIMER/CLOCK SET key
STOP/CLEAR key
GRILL key

NOTE: If the clock has been set, some one-touch cooking features such as "AUTO MINUTE" are disabled after three
minutes when the oven is not used. These features are automatically enabled when the door is opened and closed
or the STOP/CLEAR key is pressed.

R-895M - 6
OPERATION SEQUENCE
OFF CONDITION
Closing the door activates the monitored latch switch and
the stop switch.
IMPORTANT:
When the oven door is closed, the contacts COM-NC
of the monitor switch must be open. When the micro-
wave oven is plugged in a wall outlet (230 - 240V /
50Hz), the line voltage is supplied to the noise filter.
Figure O-1 on page 31
1. The control unit is not energized. The display shows
nothing (Fig. O-1 (a)).
2. Open the door. The contacts (COM-NC) of the moni-
tored latch switch are closed and the control unit is
energized. Then contacts of relays RY1 and RY5 are
closed, and the oven lamp will light and the display will
show "ENERGY SAVE MODE TO CANCEL ENERGY
SAVE MODE SET THE CLOCK" (Fig. O-1(b)).
3. Close the door. The contacts (COM-NC) of the moni-
tored latch switch are opened and the contacts of relay
RY1 are opened and the oven lamp will be turned off.
The display will show " . 0". (Fig. O-1(c)).
NOTE: Energy save mode
1. If the oven has not been used for more than 3 minutes,
the contacts of the relay RY5 will be opened and the
control unit will not be energized. Open and close the
door, the control unit will resume.
2. If the clock is set, this energy save mode does not work.
MICROWAVE COOKING CONDITION
HIGH COOKING
Enter a desired cooking time by touching the TIME keys
and start the oven by touching START key.
Function sequence Figure O-2 on page 32
CONNECTED COMPONENTS RELAY
Oven lamp, Turntable motor RY1
High voltage transformer RY2
Fan motor RY6
1. 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.
2. 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..
3. The 2450 MHz microwave energy produced in the
magnetron generates a wavelength of 12.24 cm. This
energy is channelled through the waveguide (trans-
port channel) into the oven cavity, where the food is
placed to be cooked.
4. When the cooking time is up, a signal tone is heard and
the relays RY1 + RY2 + RY6 go back to their home
position. The circuits to the oven lamp, high voltage
transformer, fan motor and turntable motor are cut off.
5. 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)
COM-NO Closed Opened
Monitored latch switch COM-NC Opened Closed
Stop switch
COM-NO Closed Opened
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 monitored latch switch and monitor switch are made
open. The circuit to the fan motor is cut off when the relay
RY6 is made open. The circuit to the turntable motor is cut
off when the contacts (COM-NO) of the monitored latch
switch are made open. The relay RY2 and RY6 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 time.
6. MONITOR SWITCH CIRCUIT
The monitor switch is mechanically controlled by the
oven door, and monitors the operation of the moni-
tored latch switch.
6-1. When the oven door is opened during or after the
cycle of a cooking program, the monitored latch
switch and stop switch must open their contacts
(COM-NO) first. After that the contacts (COM-NC) of
the monitor switch and monitored latchcan be closed.
6-2. When the oven door is closed, the contacts (COM-
NC) of the monitor switch SW3 must be opened and
the contacts (COM-NO) of monitor switch must be
closed. After that the contacts (COM-NO) of the
monitored latch switch and the stop switch are made
closed, and the contacts (COM-NC) of the monitored
latch switch are made open .
6-3. When the oven door is opened and the contacts
(COM-NO) of the monitored latch switch remain
closed, the fuse F8A will blow. Because the relay RY1
and monitor switch are closed and a short circuit is
caused.
MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW
COOKING
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 cur-
rent-limiting relay RY2. The following levels of microwave
power are given.
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.
GRILL COOKING CONDITION
TOP GRILL (Figure O-3a)
In this condition the food is cooked by the top grill heating
element . Programme the desired cooking time by touch-
ing the TIME keys and touh the GRILL key once. When the
STARTkey is touched, the following operations occur:
1. The numbers on the digital readout start the count
down to zero.
2. The oven lamp, cooling fan motor and turntable motor
are energized.
900W (HIGH) 
32 sec. ON
630W MEDIUM 
 HIGH Approx. 70%
100%
24 sec. ON 8 sec. OFF
14 sec. OFF
20 sec. OFF
26 sec. OFF
450W (MEDIUM) Approx. 50%
18 sec. ON
270W MEDIUM 
 LOW Approx. 30%
12 sec. ON
90W (LOW) Approx. 10%
6 sec. ON

R-895M - 7
3. The relay RY3 is energized and the main supply
voltage is applied to the top grill heating element .
4. Now, the food is cooked by the top grill heating ele-
ment.
BOTTOM GRILL (Figure O-3b)
In this condition the food is cooked by bottom grill heating
element energy. Programme the desired cooking time by
touching the TIME keys and touch the GRILL key twice.
When the STARTkey is touched, the following operations
occur:
1. The numbers on the digital readout start the count
down to zero.
2. The oven lamp, cooling fan motor and turntable motor
are energized.
3. The relay RY4 is energized and the main supply
voltage is applied to the bottom grill heating element .
4. Now, the food is cooked by the bottom grill heating
element .
TOP AND BOTTOM GRILL (Figure O-3c)
In this condition the food is cooked by top and bottom grill
heating elements energy. Programme the desired cook-
ing time by touching the TIME keys and touch the GRILL
key three times. When the STARTkey is touched, the
following operations occur:
1. The numbers on the digital readout start the count
down to zero.
2. The oven lamp, cooling fan motor and turntable motor
are energized.
3. The relay RY4 is energized and the main supply
voltage is applied to the bottom grill heating element.
4. The relay RY3 is energized and the main supply
voltage is applied to the top grill heating element.
5. Now, the food is cooked by the top and bottom grill
heating elements.
CONVECTION COOKING CONDITION
PRE-HEATING (Figure O-4)
Programme the desired convection temperature by touch-
ing CONVECTION TEMPERATURE key. When the
STARTkey is touched, the following operations occur:
1. The coil shut-off relays RY1 and RY6 are energized,
the oven lamp, cooling fan motor and turntable motor
are turned on.
2. The coil shut-off relays RY3 and RY4 are energized by
control unit and the main supply voltage is added to the
top and bottom heating elements.
3. When the oven temperature reaches the selected pre-
heat temperature, the following operations occur:
3-1. The coil shut-off relays RY3 and RY4 are energized
by control unit temperature circuit and thermistor,
opening the circuit to the top and bottom grill heating
elements.
3-2. The oven will continue to function for 30 minutes,
turning the top and bottom heating elements on and
off, as needed to maintain the selected pre-heat
temperature. The oven will shut-down completely
after 30 minutes.
CONVECTION COOKING (Figure O-4)
When the pre-heat temperature is reached, a beep signal
will sound indicating that the holding temperature has
been reached in the oven cavity. Open the door and place
the food to be cooked in the oven. Program desired
cooking time by touching the TIME keys and program
convection temperature by touching the CONVECTION
TEMPERATURE key . When the START key is touched,
the following operations occur:
1. The numbers on the digital readout start the count
down to zero.
2. The oven lamp, cooling fan motor, turntable motor and
convection motor are energized.
NOTE: When the convection temperature 40˚C is se-
lected, the convection motor is not energized.
3. The relays RY3 and RY4 are energized (if the cavity
temperature is lower than selected temperature) and
the main supply voltage is applied to the top and
bottom heating elements to return to the selected
cooking temperature.
4. Upon completion of the cooking time, the audible sig-
nal will sound, and the oven lamp, turntable motor,
cooling fan motor, convection motor, top and bottom
heating elements are de-energized. At the end of
convection cycle, if the cavity air temperature rises
above 120˚C, the circuit to the relay RY6 will be main-
tained (by the thermistor circuit) to continue operation
of the cooling fan motor until temperature drops below
105˚C, at that time the relay RY6 will be de-energized,
turning off the fan motor.
DUAL COOKING CONDITION
MICROWAVE AND CONVECTION (Figure O-5a)
Programme the desired cooking time by touching the
TIME keys. Touch the DUAL CONVECTION/GRILL key
once. Select the microwave power level by touching the
MICROWAVE POWER LEVEL key. And select the con-
vection temperature by touching the CONVECTION TEM-
PERATURE key.
When the STARTkey is touched, the following operations
occur:
1. The numbers on the digital readout start the count
down to zero.
2. The oven lamp, cooling fan motor, turntable motor and
convection motor are energized.
3. The relay RY3 will be energized and the main supply
voltage is applied to the top grill heatier.
4. The relay RY4 is energized (if the cavity temperature is
lower than selected temperature) and the main supply
voltage is applied to the bottom heating elementer.
5. The relay RY2 is energized and the microwave energy
is generated by magnetron.
6. Now, the food is cooked by microwave and convection
energy simultaneously.
MICROWAVE AND TOP GRILL (Figure O-5b)
Programme the desired cooking time by touching the
TIME keys. Touch the DUAL CONVECTION/GRILL key
twice. Select the microwave power level by touching the
MICROWAVE POWER LEVEL key. When the STARTkey
is touched, the following operations occur:
1. The numbers on the digital readout start the count
down to zero.
2. The oven lamp, cooling fan motor and turntable motor
are energized.
3. The relay RY3 is energized and the main supply
voltage is applied to the top grill heating element.
4. The relay RY2 is energized and the microwave energy
is generated by magnetron.
5. Now, the food is cooked by microwave and top grill
simultaneously.
OPERATION SEQUENCE

R-895M - 8
MICROWAVE AND BOTTOM GRILL (Figure O-5c)
Programme the desired cooking time by touching the
TIME keys. Touch the DUAL CONVECTION/GRILL three
times. Select the microwave power level by touching the
MICROWAVE POWER LEVEL key. When the STARTkey
is touched, the following operations occur:
1. The numbers on the digital readout start the count
down to zero.
2. The oven lamp, cooling fan motor and turntable motor
are energized.
3. The relay RY4 is energized and the main supply
voltage is applied to the bottom grill heating element.
4. The relay RY2 is energized and the microwave energy
is generated by magnetron.
5. Now, the food is cooked by microwave and bottom grill
simultaneously.
ON/OFF TIME RATIO
In grill cooking, convection cooking or dual cooking, the
top heater, bottom heater or magnetron operate whithin a
54 second time base. The following table is the ON / OFF
time ratio at each power output of the top heaters, bottom
heater or magnetron.
POWER OUTPUT ON TIME OFF TIME
100% 54 sec. 0 sec.
90% 49 sec. 5 sec.
80% 45 sec. 9 sec.
70% 40 sec. 14 sec.
60% 36 sec. 18 sec.
50% 29 sec. 25 sec.
40% 24 sec. 30 sec.
30% 18 sec. 36 sec.
20% 13 sec. 41 sec.
10% 9 sec. 45 sec.
AUTOMATIC COOKING
PIZZA
BREAKFAST
EXPRESS COOK
EXPRESS DEFROST
MEAL IN ONE
Above functions are automatic cooking. They automati-
cally work out the correct cooking mode and cooking time
and/or cooking temperature. They will cook according to
the special cooking sequence.
AUTO POWER CONTROL OPERATION
The magnetron, top or bottom heating elements, the fan
motor or the convection motor will operate in accordance
with following specification.
The power level is not reduced 1 time cooking. But only in case same menu is repeated within
1min 15sec, the power level of micro and grill is reduced from 100% to 70% in 20mins after
starting of last cooking. (Even if the time of the last cooking is longer than 20mins, the power
level isn't reduced on the last cooking, and it is reduced from the beginning of the next
cooking.) However, in time calculated from the start of the 1st cooking, even if the Cook mode
changed, when repetition cooking of the menu with which 100% of top & bottom heaters
continues are performed, as shown in the following table, the power down of the cooking of
the 2nd henceforth is carried out. (The 1st cooking is not applied)
In case same cooking mode is repeated within 1min 15sec (including stop, end), oven
calculates total cooking time and reduce the power level.
1. OUTPUT POWER CONTROL (MANUAL COOK)
OPERATION MODE DEVICE POWER CONTROL
MICROWAVE (100%)
SINGLE OPERATION Microwave 100% 20min, then 70%
TOP GRILL (100%)
SINGLE OPERATION Top heater 100% 15min, then 50%
BOTTOM GRILL (100%)
SINGLE OPERATION Bottom heater 100% 15min, then 50%
TOP(100%)/BOTTOM(100%) Top heater 100% 6min then 70% and 70% 9min then 50%
DUAL OPERATION Bottom heater 100% 6min then 70% and 70% 9min then 50%
MICRO(100%)/TOP GRILL(100%) Microwave 100% 20min, then 70%
DUAL OPERATION Top heater 100% 15min, then 50%
MICRO(70 - 10%)/TOP GRILL(100%) Microwave -
DUAL OPERATION Top heater 100% 15min, then 50%
MICRO(100%)/BOTTOM GRILL(100%) Microwave 100% 20min, then 70%
DUAL OPERATION Bottom heater 100% 15min, then 50%
MICRO(70 - 10%)/BOTTOM GRILL(100%) Microwave -
DUAL OPERATION Bottom heater 100% 15min, then 50%
Microwave
Repeat Cook Top heater
Bottom heater
2. OUTPUT POWER CONTROL (AUTO COOK)
Repeat Auto Cook
OPERATION SEQUENCE

R-895M - 9
FUNCTION OF IMPORTANT COMPONENTS
3. COOLING FAN OPERATION
OPERATION MODE DEVICE POWER CONTROL
PREHEAT Cooling 60%
CONV. Cooling fan 60% 60 min. then 100%
Others Cooling fan 100%
After cooking Cooling fan
Indication
4. CONVECTION POWER SETTING
PREHEATING
TEMP 250˚C, 230˚C, 220˚C, 200˚C, 180˚C, 160˚C, 130˚C, 100˚C, 70˚C, 40˚C
HEATING TOP 100%
ELEMENT BOTTOM 100%
COOLING FAN 60%
CONV. FAN 0%
CONVECTION
TEMP 250˚C230˚C220˚C200˚C180˚C160˚C130˚C100˚C70˚C40˚C
WITHOUT HEATING TOP 50% 40% 40% 30% 20% 10% 10% 10% 10% 10%
PREHEATING ELEMENT BOTTOM 100% 90% 80% 70% 70% 60% 50% 40% 30% 20%
WITH HEATING TOP 50% 40% 40% 30% 20% 10% 10% 10% 10% 10%
PREHEATING ELEMENT BOTTOM 90% 70% 60% 50% 50% 50% 50% 40% 30% 20%
COOLING FAN 60% 60min, then 100%
CONV. FAN 100% 0%
DUAL CONVECTION
TEMP 250˚C230˚C220˚C200˚C180˚C160˚C130˚C100˚C70˚C40˚C
WITHOUT HEATING TOP 50% 40% 40% 30% 20% 10% 10% 10% 10% 10%
PREHEATING ELEMENT BOTTOM 100% 90% 80% 70% 70% 60% 50% 40% 30% 20%
WITH HEATING TOP 50% 40% 40% 30% 20% 10% 10% 10% 10% 10%
PREHEATING ELEMENT BOTTOM 90% 70% 60% 50% 50% 50% 50% 40% 30% 20%
MICRO 10%,30%,50%
COOLING FAN 100%
CONV. FAN 100% 0%
NOTE The oven temp was checked by the thermometer when each stages are started .
If the oven temp is same or higher than 105˚C, the oven was judged as "with preheating".
When the oven temp is lower than 105˚C or the cooling fan stops, the oven was judged as "without
preheating".
The cooling fan continues to rotate when Oven temperature is more than 120˚C. Then,
it stops when it is less than 105˚C
NOW COOLING is indicated during the cooling fan movement after operation is finished.
(It isn't indicated during a fan movement to stop on the way.)
Latch hook
Door
SW2: Stop switch
Latch
Heads
SW3: Monitor switch
SW1:Monitored
 latch switch
Tab
The door can be opened by pulling the door handle. When
the handle is pulled, the latch head is pulled, the latch head
is moved upward, and released from the latch hook now
the door can be opened.
MONITORED LATCH SWITCH
1. When the oven door is closed, the contacts (COM-NO)
of the switch must be closed. And the contacts (COM-
NC) must be opened.
2. When the oven door is opened, the contacts (COM-
NO) of the switch must be opened. And the contacts
(COM-NC) must be closed.
OPERATION SEQUENCE
Figure D-1. Door Open Mechanism

R-895M - 10
STOP SWITCH
1. When the oven door is closed, the contacts (COM-NO)
of the switch must be closed.
2. When the oven door is opened, the contacts (COM-
NO) of switch must be opened.
MONITOR SWITCH
The monitor switch is activated (the contacts opened) by the
upper latch head on the door while the door is closed. The
switch is intended to render the oven inoperative by means of
blowing the fuse F8A when the contacts of the monitored
latch switch fail to open when the door is opened.
Function
1. When the door is opened, the contacts (COM-NC) of
monitor switch close (to the ON condition) due to their
being normally closed and contacts (COM-NO) open.
At this time the contacts (COM-NO) of monitored latch
switch is in the OFF condition (contacts open) due to
their being normally open contact switches.
2. As the door goes to a closed position, the monitor switch
contacts (COM-NC) are opened and contacts (COM-
NO) closed and then contacts (COM-NO) of monitored
latch switch and stop switch are closed.(On opening the
door, each of these switches operate inversely.)
3. If the door is opened and the monitored latch switch
contacts (COM-NO) fail to open, the fuse F8A blows
immediately after closing of the monitor switch (COM-
NC) contacts.
CAUTION: BEFORE REPLACING A BLOWN FUSE F8A,
TEST THE MONITORED LATCH SWITCH
AND MONITOR SWITCH FOR PROPER
OPERATION. (REFER TO CHAPTER “TEST
PROCEDURE”).
FUSE 15A 250V
If the wire harness or electrical components are short-
circuited, this fuse blows to prevent an electric shock or
fire hazard.
FUSE F8A 250V
1. If the wire harness or electrical components are short-
circuited, this fuse blows to prevent an electric shock or
fire hazard.
2. The fuse also blows when the monitored latch switch
remains closed with the oven door open and when the
monitor switch contact (COM-NC) closes.
3. The fuse also blows when the asymmetric rectifier, H.V.
rectifier,.H.V. wire harness, H.V. capacitor, magnetron or
secondary winding of high voltage transformer is shorted.
TC TRANSFORMER
T/C transformer converts A.C. line voltage into low voltage
to drive the control unit.
THERMAL CUT-OUT 125˚C (MG)
This thermal cut-out protects the magnetron against over-
heat. If the temperature goes up higher than 125˚C be-
cause the fan motor is interrupted or the ventilation open-
ings are blocked, the thermal cut-out will open and line
voltage to the high voltage transformer will cut off and
operation of the magnetron will be stopped. The defec-
tive thermal cut-out must be replaced with a new one.
THERMAL CUT-OUT 145˚C (OVEN)
This thermal cut-out protects against overheat ing /fire inside
the oven. The cut-out contacts will open when temperatures
exceed 145˚C.When the cut-out cools itself down to the
operating temperature of 115˚C, the contacts of the thermal
cut-out will close again.
ASYMMETRIC RECTIFIER
The asymmetric rectifier is solid state device that prevents
current flow is both directions. And it prevents the tem-
perature rise of the high voltage transformer by blowing
the fuseF8A when the high voltage rectifier is shorted.
The rated peak reverse voltage of D1 of the asymmetric
rectifier is 6 KV. The rated peak reverse voltage of D2 of
the asymmetric rectifier is 1.7 KV. D1 and D2 of the
asymmetric rectifier or high voltage rectifier are shorted
when the each peak reverse voltage goes beyond the
each rated peak reverse voltage. (The process of the
blowing the fuseF8A.)
D2 D1
ASYMMETRIC
RECTIFIER HIGH VOLTAGE
RECTIFIER
AB
C
1. The high voltage rectifier is shorted by some fault when
microwave cooking or dual cooking.
2. The peak reverse voltage of D2 of the rectifier goes
beyond the rated peak reverse voltage 1.7 KV in the
voltage doubler circuit.
3. D2 of the rectifier is shorted.
4. The large electric currents flow through the high volt-
age winding of the high voltage transformer.
5. The large electric currents beyond 8A flow through the
primary winding of the high voltage transformer.
6. The fuse F8A blows by the large electric currents.
7. The power supplying to the high voltage transformer is
cut off.
NOISE FILTER
The noise filter assembly prevents radio frequency inter-
ference that might flow back in the power circuit.
TURNTABLE MOTOR
The turntable motor rotates the turntable.
FAN MOTOR
The fan motor drives a blade which draws external cool air.
This cool air is directed through the air vanes surrounding
the magnetron and cools the magnetron. This air is chan-
nelled through the oven cavity to remove steam and
vapours given off from heating food. It is then exhausted
through the exhausting air vents of the oven cavity.
CONVECTION MOTOR
The convection motor drives the convection fan and
provide the heated air.
TOP GRILL HEATING ELEMENT
The grill heating element is provided to brown the food and
is located on the top of the oven cavity.
FUNCTION OF IMPORTANT COMPONENTS

R-895M - 11
FUNCTION OF IMPORTANT COMPONENTS
BOTTOM GRILL HEATING ELEMENT
The grill heating element is provided to brown the food and
is located at the base of the oven cavity.
CONVECTION COOKING SYSTEM
This oven is designed with a hot air heating system where
food is heated be forced circulation of the hot air produced
by the grill heaters. The air heated be the grill heating
elements is circulated through the convectin passage
provided on the outer casing of the oven cavity be means
of the convection fan which is driven by the convection
motor. It then enters the inside of the oven through the
vent holes provided on the back of the oven. Next, the hot
air heats the food on the turntable and leaves the oven
cavity through the vent in the oven cavity rear wall. In this
way, the hot air ciculates inside the oven cavity to raise its
temperature and at the same time, comes into contact
with the food cooked. When the temperature inside the
oven cavity reaches the selected temperature, the heat-
ing elements are de-energized. When the temperature
inside the oven cavity drops below the selected tempera-
ture, the elements are energized again. In thia way, the
inside of the oven is maintained at approximately the
selected temperature. When the convection time reaches
"0", the heating elements are de-energzed and the con-
vection fan stops operating and the oven shuts off. At that
time if the cavity air temperature has rised above 120oC,
the fan remains rotating. Automatically the fan motor will
shut down at low temperature (less than 105oC).
FIRE SENSING FEATURE
The oven will stop its operation when there is a fire in the
oven cavity in microwave cooking condition.
LSI measures the voltage across the temperature meas-
urement circuit intermittently within 32-seconds time base
since the oven is started in microwave cooking condition.
The oven will stop its operation when the difference of the
voltage is more than 0.781 volts in microwave cooking
condition.
1. Within a 32-seconds base, the thermistor is energized
for 2 seconds. At that time, the voltage across the
temperature measurement circuit is measured.
2. The oven carries out the procedure above again. If the
second voltage is 0.781V higher than first voltage, LSI
judges it is a fire in the oven cavity and stop the oven.
3. When LSI judges it is a fire in the oven cavity, LSI will
switch off the relays to high voltage transformer and fan
motor and LSI stops countring down.
OPEN JUDGE BY THERMISTOR
1. If the temperature of the thermistor does not rise to
more than 40˚C after 4 minutes and 15 seconds from
when the oven is started in oven cooking mode, dual
cooking mode or grill (top and bottom) cooking mode,
the oven is turned off.
2. When the thermistor or the wire harness to the thermis-
tor is opened, the oven is turned off after 4 minutes and
15 seconds because this condition is same as above
Figure D-2. Convection Cooking system
THERMISTOR
SENSING
VOLTAGE
ON
OFF
ON
OFF
30 32 (sec.)
Sensing the voltage across temperature measurement circuit.
Door Oven Cavity Grill Heating
Element
Bottom Grill 
Heating Element
Convection
Passage
Cooling
Fan
Convection

Motor
Convection

Fan
Turntable
Insulation
Turntable
Motor

R-895M - 12
Fuse F8A blows when the door is opened. Home fuse blows when power cord is plugged into wall outlet. Fuse 15A blows when power cord is plugged into wall outlet. Nothing appears in display when power cord is plugged into wall outlet and the door is opened and closed. Display does not operate properly when STOP/CLEAR key is touched. Oven lamp does not light when door is opened. (Display operates.) Oven does not start when the START key is touched. (Display operates.) Oven lamp does not light and turntable motor does not operate. Fan motor does not operate. (Oven lamp lights.) Convection fan motor does not operate. (Oven lamp lights.) Turntable motor does not operate. (Oven lamp lights.) Oven or any electrical parts (except fan motor) does not stop when cooking time is 0 or STOP/CLEAR key is touched. Oven stops after 4 minutes and 15 seconds since START key is touched. (Except Microwave mode) Display operates properly but all electrical parts do not operate. Oven goes into cook cycle but shuts down before end of cooking cycle. After cooking, the temperature of oven cavity is higher than 105˚C but fan motor does not operate. Oven seems to be operating but little or no heat is produced in oven load. (Microwave power control is set at HIGH) Oven does not seem to be operating properly during variable cooking condition except HIGH cooking condition. Oven goes into cook cycle but shuts down before end of cooking cycle. Convection cooking mode does not heat. Oven seems to be operating but the temperature in the oven cavity is lower or higher than preset one. Grill heating element does operate. Oven goes into cook cycle but shuts down before end of cooking cycle. Oven seems to be operating but little or no heat is produced in oven load. (Microwave power does not seem to be generated properly) Oven seems to be operating but the temperature in the oven cavity is lower or higher than preset one. Top and Bottom Grill heating elements do not heat. Top or Bottom Grill heating element does not heat.
OFF
CONDITION
COOKING
CONDITION
(COMMON MODE)
MICROWAVE
COOKING
CONDITION
GRILL COOKING
CONDITION
CONVECTION
COOKING
CONDITION
DUAL COOKING
CONDITION
(COMMON MODE)
DUAL COOKING
CONDITION
(MICRO./CONV.)
DUAL COOKING
CONDITION
(MICRO./GRILL)
CONDITION
PROBLEM
BLOCKED COOLING FAN
BLOCKED CONVECTION FAN
NO POWER AT WALL OUTLET
HOME FUSE OR BREAKER
MIS-ADJUSTMENT OF SWITCHES
BLOCKED VENTILATION OPENINGS
OPENED WIRE HARNESS
SHORTED WIRE HARNESS
OVEN LAMP OR SOCKET
POWER SUPPLY CORD
FOIL PATTERN ON P.W.B.
RELAY RY7
RELAY RY6
RELAY RY5
RELAY RY4
RELAY RY3
RELAY RY2
RELAY RY1
KEY UNIT
TOUCH CONTROL PANEL
TC TRANSFORMER
BTTOM GRILL HEATING ELEMENT
TOP GRILL HEATING ELEMENT
FUSE F8A
FUSE 20A
NOISE FILTER
CONVECTION FAN MOTOR
FAN MOTOR
TURNTABLE MOTOR
THERMAL CUT-OUT 145˚C (OVEN)
THERMAL CUT-OUT 125˚C (MG)
THERMISTOR
MONITOR SWITCH
STOP SWITCH
MONITORED LATCH SWITCH
HIGH VOLTAGE CAPACITOR
H.V. HARNESS
H.V. RECTIFIER ASSEMBLY
HIGH VOLTAGE TRANSFORMER
MAGNETRON
A B C D E E E F G G H H H
TEST PROCEDURE
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
I J K L L M N O O O O O O O P Q
TROUBLESHOOTING GUIDE

R-895M - 13
AMAGNETRON TEST
CARRY OUT 3D CHECKS.
Isolate the magnetron from high voltage circuit by removing all leads connected to filament terminal.
To test for an open circuit filament use an ohmmeter to make a continuity test between the magnetron
filament terminals, the meter should show a reading of less than 1 ohm.
To test for short filament to anode condition, connect ohmmeter between one of the filament terminals
and the case of the magnetron (ground). This test should be indicated an infinite resistance. If a low
or zero resistance reading is obtained then the magnetron should be replaced.
MICROWAVE OUTPUT POWER
The power output of this oven is rated using the method specified by IEC 60705. Full details of how
to curry out this procedure can be found in the Sharp Technical Training notes which is available from
Sharp Parts Centre (part number SERV-LITMW01).
The IEC-60705 procedure must be carried out using laboratory-type procedures and equip-
ment.
These requirements make the procedure unsuitable for routine performance checks.
NOTE: The following test method gives an indication of the output power only, it cannot be used to
establish the actual/rated output power. If the true output power is required, then the IEC705
test method must be used.
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 1 minute and 36 seconds on full power.
NOTE: The operation time of the microwave oven includes "3" sec. (3 sec. is magnetron filament
heat-up time.)
4. When the 1 minute and 36 seconds is completed, remove the container and stir the water. Note
temperature as T2.
5. Calculate the output power using the following formula:
R.F. Power Output = (T2 - T1) x 90.
NOTE: The result from this test should be within the allowance of 2000cc alternative method.
(±10%).
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/m2 (equivalent to 5W/m2), 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 National Physical
Laboratories are used.
Suitable leakage detectors: CELTEC A100
APOLLO X1
NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL
WHILE THE OVEN IS IN OPERATION.
PROCEDURE
LETTER COMPONENT TEST
TEST PROCEDURES

R-895M - 14
CHIGH VOLTAGE RECTIFIER TEST
CARRY OUT 3D CHECKS.
Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be tested
using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal B+C of the high
voltage rectifier and note the reading obtained. Reverse the meter leads and note this second reading.
The normal resistance is infinite in one direction and more than 100 kΩin the other direction.
CARRY OUT 4R CHECKS.
ASYMMETRIC RECTIFIER TEST
CARRY OUT 3D CHECKS.
Isolate the high voltage rectifier assembly from the HV circuit. The asymmetric rectifier can be tested
using an ohmmeter set to its highest range across the terminals A+B of the asymmetric rectifier and
note the reading obtained. Reverse the meter leads and note this second reading. If an open circuit is
indicated in both directions then the asymmetric rectifier is good. If the asymmetric rectifier is shorted
in either direction, then the asymmetric rectifier is probably faulty and must be replaced with high voltage
rectifier. When the asymmetric rectifier is defective, check whether magnetron, high voltage rectifier,
high voltage wire or filament winding of the high voltage transformer is shorted.
CARRY OUT 4R CHECKS.
NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, THE BATTERIES OF
THE MEASURING INSTRUMENT MUST HAVE A VOLTAGE AT LEAST 6 VOLTS, BECAUSE
OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIRECTIONS.
CARRY OUT 3D CHECKS.
Disconnect the leads to the primary winding of the high voltage transformer. Disconnect the filament
and secondary winding connections from the rest of the HV circuitry. Using an ohmmeter, set on a low
range, it is possible to check the continuity of all three winding. The following readings should be
obtained:-
a. Primary winding ................................ approximately 1.9 Ω
b. Secondary winding .......................... approximately 124 Ω
c. Filament winding ......................................... less than 1 Ω
If the readings obtained are not stated as above, then the high voltage transformer is probably faulty
and should be replaced.
CARRY OUT 4R CHECKS.
D2 D1
ASYMMETRIC
RECTIFIER
HIGH VOLTAGE RECTIFIER
CARRY OUT 3D CHECKS.
A. Isolate the high voltage capacitor from the circuit.
B. Continuity check must be carried out with measuring instrument which is set to the highest
resistance range.
C. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10MΩ
after it has been charged.
D. A short-circuited capacitor shows continuity all the time.
E. An open capacitor constantly shows a resistance about 10 MΩbecause of its internal 10MΩ
resistance.
F. When the internal wire is opened in the high voltage capacitor shows an infinite resistance.
G. The resistance across all the terminals and the chassis must be infinite when the capacitor is
normal.
If incorrect reading are obtained, the high voltage capacitor must be replaced.
CARRY OUT 4R CHECKS.
DHIGH VOLTAGE CAPACITOR TEST
WARNING: High voltage and large currents are present at the secondary winding and
filament winding of the high voltage transformer. It is very dangerous to work
near this part when the oven is on. NEVER make any voltage measurements
of the high-voltage circuits, including the magnetron filament.
TEST PROCEDURES
BHIGH VOLTAGE TRANSFORMER TEST
PROCEDURE
LETTER COMPONENT TEST

R-895M - 15
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the thermal cut-out. Then using an ohmmeter, make a
continuity test across the two terminals as described in the below.
Table: Thermal Cut-out Test
Temperature of "ON" Temperature of "OFF" Indication of ohmmeter
Parts Name condition (closed circuit). condition (open circuit). (When room temperature
(˚C) (˚C) is approx. 20˚C.)
Thermal cut-out 125˚C This is not resetable Above 125˚CClosed circuit
Thermal cut-out 145˚C Below 115˚C. Above 145˚CClosed circuit
If incorrect readings are obtained, replace the thermal cut-out.
An open circuit thermal cut-out (MG) indicates that the magnetron has overheated, this may be due to
resistricted ventilation, cooling fan failure.
An open circuit thermal cut-out (OVEN) indicates that the oven cavity has overheated, this may be due
to no load operation,or excessive heat / fire inside the oven.
CARRY OUT 4R CHECKS.
ESWITCH TEST
Table: Terminal Connection of Switch
Plunger Operation COM to NO COM to NC
Released Open circuit Short circuit
Depressed Short circuit Open circuit
COM; Common terminal,
NO; Normally open terminal
NC; Normally close terminal
If incorrect readings are obtained,replace the switch.
CARRY OUT 4R CHECKS.
CARRY OUT 3D CHECKS.
Isolate the switch to be tested and using an ohmmeter check between the terminals as described in
the following table.
F THERMISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect the connector B from CPU unit. Measure the resistance of the thermistor with an
ohmmeter. Connect the ohmmeter leads to Pin No's C1 and C3 of the thermistor harness.
Room Temperature Resistance
20˚C - 30˚C Approximately 359.9 kΩ- 152 kΩ
If the meter does not indiicate above resistance, replace the thermistor.
CARRY OUT 4R CHECKS.
PROCEDURE
LETTER COMPONENT TEST
GTHERMAL CUT-OUT TEST
HMOTOR WINDING TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two
terminals as described in the table below.
Table: Resistance of Motor
Motors Resistance
Fan motor Approximately 293 Ω
Turntable motor Approximately 15 kΩ
Convection fan motor Approximately 288 Ω
TEST PROCEDURES