Sharp R-318BK User manual

R-318BK
TABLE OF CONTENTS Page
PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO
AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY ...................INSIDE FRONT COVER
BEFORE SERVICING ......................................................................................................INSIDE FRONT COVER
WARNING TO SERVICE PERSONNEL................................................................................................................1
MICROWAVE MEASUREMENT PROCEDURE ...................................................................................................2
FOREWORD AND WARNING...............................................................................................................................3
PRODUCT SPECIFICATIONS ..............................................................................................................................4
SCHEMATIC DIAGRAM ........................................................................................................................................5
TEST PROCEDURE ..............................................................................................................................................6
POWER UNIT CIRCUIT ........................................................................................................................................7
CPU UNIT CIRCUIT ..............................................................................................................................................8
PRINTED WIRING BOARD ...................................................................................................................................9
PARTS LIST ........................................................................................................................................................10
PACKING AND ACCESSORIES .........................................................................................................................14
S915R318BPK/
MICROWAVE OVEN
MODEL R-318BK
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.
WARNING TO SERVICE PERSONNEL: Microwave ovens con-
tain circuitry capable of producing very high voltage and
current, contact with following parts may result in a severe,
possibly fatal, electrical shock. (High Voltage Capacitor, High
VoltagePowerTransformer,Magnetron,HighVoltageRectifier
Assembly, High Voltage Harness etc..)
SHARP CORPORATION This document has been published to be used for after
sales service only.
The contents are subject to change without notice.
SUPPLEMENTAL SERVICE MANUAL
This is a supplemental Service Manual for Model R-318BK. This model is quite similar to base
model R-320BK. Use this supplemental manual together with the Base Model Service Manual
(Refer No. is S2805R320BPW/) for complete operation, service information, etc..
BAKED
POTATO
GROUND
MEAT CHICKEN
BREAST
FRESH/
SEAFOOD
GROUND
MEAT
KITCHEN
TIMER MINUTE
PLUS
AUTO START
CLOCK
CHICKEN
PIECES
STEAKS/
CHOPS
POPCORN
FRESH VEGETABLE
FRESH ROLL FROZEN ROLL
FROZEN ENTREES
REHEAT
SENSOR COOK
INSTANT ACTION
COMPU DEFROST
TO ADJUST QUANTITY . TOUCH PAD AGAIN
POWER
LEVEL START
STOP

CLEAR

R-318BK
PRECAUTIONSTO BE OBSERVED BEFORE AND
DURING SERVICINGTO AVOID POSSIBLE
EXPOSURETO EXCESSIVE MICROWAVE
ENERGY
(a) Do not operate or allow the oven to be operated with the door open.
(b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other
microwave source, and make repairs as necessary: (1) interlock operation, (2) proper door closing, (3)
seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and
latches, (5) evidence of dropping or abuse.
(c) Before turning on microwave power for any service test or inspection within the microwave generating
compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment,
integrity, and connections.
(d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave
generation and transmission systems shall be repaired, replaced, or adjusted by procedures described
in this manual before the oven is released to the owner.
(e) A microwave leakage check to verify compliance with the Federal Performance Standard should be
performed on each oven prior to release to the owner.
BEFORE SERVICING
Before servicing an operative unit, perform a microwave emission check as per the Microwave
Measurement Procedure outlined in this service manual.
If microwave emissions level is in excess of the specified limit, contact SHARP ELECTRONICS
CORPORATION immediately @1-800-237-4277.
If the unit operates with the door open, service person should 1) tell the user not to operate the oven
and 2) contact SHARP ELECTRONICS CORPORATION and The Food and Drug Administration's
Center for Devices and Radiological Health immediately.
ServicepersonnelshouldinformSHARPELECTRONICSCORPORATIONofanycertifiedunitfound
with emissions in excess of 4mW/cm2. The owner of the unit should be instructed not to use the unit
until the oven has been brought into compliance.

1
R-318BK
WARNINGTO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of pro-
ducing very high voltage and current, contact with
following parts
may result in a severe, possibly
fatal, electrical shock.
(Example)
HighVoltageCapacitor,HighVoltagePowerTrans-
former,Magnetron,HighVoltageRectifierAssem-
bly, High Voltage Harness etc..
Read the Service Manual carefully and follow all
instructions.
Before Servicing
1. Disconnect the power supply cord , and then
remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
WARNING:RISK OF ELECTRIC SHOCK.
DISCHARGE THE HIGH-VOLTAGE
CAPACITOR BEFORE SERVICING.
The high-voltage capacitor remains charged about 60
secondsaftertheovenhasbeenswitchedoff.Waitfor60
secondsandthenshort-circuittheconnectionofthehigh-
voltagecapacitor (thatis theconnectingleadofthe high-
voltage rectifier) against the chassis with the use of an
insulated screwdriver.
Whenever troubleshooting is performed the power supply
mustbedisconnected.Itmayin,somecases,benecessary
to connect the power supply after the outer case has been
removed, in this event,
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power
transformer.
5. Ensure that the leads remain isolated from other
components and oven chassis by using insulation tape.
6. After that procedure, reconnect the power supply cord.
When the testing is completed,
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Reconnect the leads to the primary of the power
transformer.
5. Reinstall the outer case (cabinet).
6. Reconnectthepower supplycord afterthe outercase is
installed.
7. Run the oven and check all functions.
After repairing
1. Reconnect all leads removed from components during
testing.
2. Reinstall the outer case (cabinet).
3. Reconnectthepower supplycord afterthe outercase is
installed.
4. Run the oven and 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
remainscoldcarryoutBeforeServicingprocedureandre-
examine the connections to the component being tested.
When all service work is completed and the oven is fully
assembled,themicrowavepoweroutputshouldbechecked
and microwave leakage test should be carried out.
Don't Touch !
Danger High Voltage

2
R-318BK
MICROWAVE MEASUREMENT PROCEDURE
A. Requirements:
1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven
shouldnotexceed1mW/cm2atanypoint5cmormorefromtheexternalsurfaceoftheoven,measuredpriortoacquisition
bya purchaser,andthereafter (throughtheuseful lifeof theoven),5 mW/cm2atany point5cmor morefromthe external
surface of the oven.
2) Safety interlock switches Primary interlock relay and door sensing switch shall prevent microwave radiation emission in
excess of the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission
in excess of 5 mW/cm2at any point 5cm or more from the external surface of the oven.
B. Preparation for testing:
Before beginning the actual measurement of leakage, proceed as follows:
1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.
Important:
Surveyinstruments that complywith therequirement forinstrumentation asprescribed bythe performancestandard
for microwave ovens, 21 CFR 1030.10(c)(3)(i), must be used for testing.
2) Place the oven tray in the oven cavity.
3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5˚C (68˚F) in the center of the oven cavity.
The water container shall be a low form of 600 ml (20 oz) beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.)
and made of an electrically nonconductive material such as glass or plastic.
Theplacingof thisstandard loadin the ovenis importantnot onlyto protect theoven, butalso toinsure that anyleakage
is measured accurately.
4) Set the cooking control on Full Power Cooking Mode
5) Close the door and select a cook cycle of several minutes. If the water begins to boil before the survey is completed,
replace it with 275 ml of cool water.
C. Leakage test:
Closed-door leakage test (microwave measurement)
1) Grasptheprobeofthesurveyinstrumentandholditperpendiculartothegapbetweenthedoorandthebodyoftheoven.
2) Move the probe slowly, not faster than 1 in./sec. (2.5 cm/sec.) along the gap, watching for the maximum indication on
the meter.
3) Checkforleakageatthedoorscreen,sheetmetalseamsandotheraccessiblepositionswherethecontinuityofthemetal
has been breached (eg., around the switches, indicator, and vents).
Whiletestingforleakagearoundthedoorpullthedoorawayfromthefrontoftheovenasfarasispermittedbytheclosed
latch assembly.
4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2,
and that the secondary interlock switch does turn the oven OFF before any door movement.
NOTE: After servicing, record data on service invoice and microwave leakage report.

3
R-318BK
SHARP ELECTRONICS CORPORATION
SHARP PLAZA, MAHWAH,
NEW JERSEY 07430-2135
SERVICE MANUAL
MICROWAVE OVEN
R-318BK
FOREWORD
This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service
Information for the SHARP MICROWAVE OVEN, R-318BK.
The model R-318BK is quite similar to base model R-320BK (Refer No. is S2805R320BPW/).
It is recommended that service personnel carefully study the entire text of this manual and the base model's manual so
that they will be qualified to render satisfactory customer service.
Check the interlock switches and the door seal carefully. Special attention should be given to avoid electrical shock and
microwave radiation hazard.
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 no other visible damage with the oven.
Servicing and repair work must be carried out only by trained service personnel.
DANGER
Certaininitialpartsareintentionallynotgroundedandpresentariskofelectricalshockonlyduringservicing.
Service personnel - Do not contact the following parts while the appliance is energized;
High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage
Harness;
If provided, Vent Hood, Fan assembly, Cooling Fan Motor.
All the parts marked “*” on parts list are used at voltages more than 250V.
Removal of the outer wrap gives access to voltage above 250V.
All the parts marked “∆” on parts list may cause undue microwave exposure, by themselves, or when they are
damaged, loosened or removed.

4
R-318BK
ITEM DESCRIPTION
Power Requirements 120 Volts / 14 Amperes
60 Hertz
Single phase, 3 wire grounded
Power Output 1100 watts (IEC-705 TEST PROCEDURE)
Operating frequency of 2450MHz
Case Dimensions Width 20-1/2"
Height 11-7/8"
Depth 15-7/8"
Cooking Cavity Dimensions Width 13-3/4"
Height 8-3/8"
1.0 Cubic Feet Depth 14-7/8"
Control Complement Touch Control System
Clock ( 1:00 - 12:59 )
Timer (0 - 99 min. 99 seconds)
Microwave Power for Variable Cooking
Repetition Rate;
P-HI..................................................Full power throughout the cooking time
P-90 .................................................................... approx. 90% of Full Power
P-80 .................................................................... approx. 80% of Full Power
P-70 .................................................................... approx. 70% of Full Power
P-60 .................................................................... approx. 60% of Full Power
P-50 .................................................................... approx. 50% of Full Power
P-40 .................................................................... approx. 40% of Full Power
P-30 .................................................................... approx. 30% of Full Power
P-20 .................................................................... approx. 20% of Full Power
P-10 .................................................................... approx. 10% of Full Power
P-0 .................................................... No power throughout the cooking time
SENSOR COOK pads, INSTANT ACTION pads
COMPU DEFROST pads, Number selection pads
KITCHEN TIMER pad, AUTO START/CLOCK pad
MINUTE PLUS pad, POWER LEVEL pad
STOP/CLEAR pad, START pad
Oven Cavity Light Yes
Safety Standard UL Listed FCC Authorized
DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J
SPECIFICATION

5
R-318BK
TOUCH CONTROL PANEL
BAKED
POTATO
GROUND
MEAT CHICKEN BREAST
FRESH/
SEAFOOD
GROUND
MEAT
KITCHEN
TIMER MINUTE PLUS
AUTO START
CLOCK
CHICKEN
PIECES
STEAKS/
CHOPS
POPCORN
FRESH VEGETABLES
FRESH ROLL FROZEN ROLL
FROZEN ENTREES
REHEAT
SENSOR COOK
INSTANT ACTION
COMPU DEFROST
TO ADJUST QUANTITY . TOUCH PAD AGAIN
POWER
LEVEL START
STOP 
CLEAR
Figure O-1. Oven Schematic-Off Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. CLOCK APPEARS ON DISPLAY
120V AC
60 Hz
OVEN
LAMP TURN-
TABLE
MOTOR FAN 
MOTOR
POWER 
TRANSFORMER
CAPACITOR 1.0µF AC 2300V
MONITOR 
SWITCH
RECTIFIER MAGNETRON
SECONDARY
INTERLOCK
SWITCH
TTM
OL FM
MONITOR 
FUSE 20A
A1
A2
COM.
COM.N.O.
N.O.
DOOR
SENSING
SWITCH
(RY-1) (RY-2)
CONTROL UNIT
PRIMARY
INTERLOCK
RELAY
THERMAL 
CUT-OUT (OVEN) THERMAL 
CUT-OUT (MG.)
SH-B SH-A
GRN
F3
F1 F2
AH SENSOR

6
R-318BK
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
J KEY UNIT TEST
TROUBLESHOOTING GUIDE
Nevertouch anypart inthe circuitwithyourhandoranuninsulatedtoolwhile thepower supplyis connected.
Whentroubleshootingthe microwaveoven,itis helpfultofollowtheSequenceofOperationinperforming thechecks.Many
ofthepossiblecausesoftroublewillrequirethataspecifictestbeperformed. Thesetestsaregivenaprocedureletter which
will be found in the "Test Procedure "section.
IMPORTANT: If the oven becomes inoperative because of a blown monitor fuse, check the monitor switch, relay (RY1)
primary interlock relay (RY2), door sensing switch and secondary interlock switch before replacing the
monitor fuse. If monitor fuse is replaced, the monitor switch must also be replaced. Use part FFS-
BA021WRK0 as an assembly.
IMPORTANT: Whenever troubleshooting is performed with the power supply cord disconnected. It may in, some cases,
be necessary to connect the power supply cord after the outer case has been removed, in this event,
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power transformer.
5. Ensurethatthe leadsremainisolatedfrom othercomponentsandovenchassisbyusinginsulationtape.
6. After that procedure, reconnect the power supply cord.
When the testing is completed
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Reconnect the leads to the primary of the power transformer.
5. Reinstall the outer case (cabinet).
6. Reconnect the power supply cord after the outer case is installed.
7. Run the oven and check all functions.
H BLOWN MONITOR FUSE TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. If the monitor fuse is blown when the door is opened, check the primary interlock relay, secondary
interlockswitchandmonitorswitchaccordingtothe"TESTPROCEDURE"forthoseswitchesbefore
replacing the blown monitor fuse.
CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY INTERLOCK
RELAY,SECONDARYINTERLOCKSWITCH,DOORSENSINGSWITCHANDMONITOR
SWITCH FOR PROPER OPERATION.
If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch must
be replaced with "monitor fuse and monitor switch assembly" part number FFS-BA021WRK0, even
ifthe monitorswitch operatesnormally. Themonitor fuseand monitorswitch assemblyis comprised
of a 20 ampere fuse and switch.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.

7
R-318BK
4. If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable
ismakinggoodcontact,verifythatthedoorsensingswitch(stopswitch)operatesproperly;thatisthe
contacts are closed when the door is closed and open when the door is open. If the door sensing
switch (stop switch) is good, disconnect the flat ribbon cable that connects the key unit to the control
unitand makesure thedoor sensingswitch isclosed (eitherclose thedoor orshort thedoor sensing
switch connecter). Use the Key unit matrix indicated on the control panel schematic and place a
jumperwire betweenthepins thatcorrespondto theSTOP/CLEAR padmakingmomentary contact.
If the control unit responds by clearing with a beep the key unit is faulty and must be replaced. If the
control unit does not respond, it is faulty and must be replaced. If a specific pad does not respond,
the above method may be used (after
clearingthecontrolunit)todetermineif
the control unit or key pad is at fault.
5. Reconnect all leads removed from
components during testing.
6. Re-install the outer case (cabinet).
7. Reconnectthe power supplycord after
the outer case is installed.
8. Run the oven and check all functions.
54321
09876
STOP
CLEAR
AUTO
START

CLOCK
Chicken
breast

KITCHEN
TIMER

Fresh
Vegetables

Fish /
seafood
Ground meat
Ground meat
COMPU
DEFROST
Chicken
pieces

PopcornReheat
START
POWER
LEVEL
MINUTE
PLUS
Fresh
roll /
muffin
Frozen
roll /
muffin
Frozen
entrees

Baked
potato
Steaks /
chops
INSTANT
ACTION
G 8
G 9
G10
G11
G12
G 7 G 6 G 5 G 4 G 3 G 2 G 1

6
45
123
6
45
123
A
B
C
D
E
F
G
H
A
B
C
D
E
F
G
H
Figure S-2. Power Unit Circuit
+
–
+
–
+
–
A 1
A 2
C 1
C 2
C 3
C 4
C 5
C 6
C 7
C 8
C 9
SH-B
SH-A
T1
AC
AC
AC
MICRO
VA
GND
VC
INT
BUZZER
MICRO
DOOR
SWITCH
NOTE : IF NOT SPECIFIED, 1/4w ±5%
: IF NOT SPECIFIED, 1SS270A
TURNTABLE
MOTOR
OVEN LAMP
FAN
MOTOR TURNTABLE
MOTOR
OVEN LAMP
FAN
MOTOR
WH-1
R4 27
R5 4.7k
R2 680 1/2w
R6 3.3k
SP1
VRS1
C1 0.1µ/50v C3 0.1µ/50v
ZD1
HZ16-1
C4 10µ/35v
C5
10µ/35v
R3 510 1/2w
C2 1000µ/35v
R1 2.4k
(J1)

D5
D3
D4 D2
D1
a
c
d
b
D6
RY1
D7
D8
RY2
Q2 2SB1238
2SB1238
Q1
D1-D4
11ES1
Q3 DTD143ES
V
R
V R
V R
V A
LD1-LD5
LD1 LD2 LD3 LD4 LD5
N.O.
N.O.
COM
COM
14
3 6

8
R-318BK
6
45
123
6
45
123
A
B
C
D
E
F
G
H
A
B
C
D
E
F
G
H
Figure S-3. CPU Unit Circuit
28
29
27 C 1
C 2
C 3
26 C 0
25 S16
24 S15
23 S14
22 S13
21 S12
20 S11
19 S10
18 S 9
17 S 8
16 S 7
15 S 6
14 S 5
13 S19
12 S20
11 S21
10 S22
9 S23
8 S24
7 S25
6 S26
5S4
4S3
3S2
2S1
1S0
27
RESET
64
SEG10
28
P71 29
P70 30
XIN 31
XOUT
80
79
COM0
78
COM1
77
COM2
76
COM3
75
74
VREF
73
AVSS
SEG8
41 63 62
SEG11
61
SEG12
60
SEG13
59
SEG14
58
SEG15
57
SEG16
56
SEG17
55
SEG18
54
SEG19
53
SEG20
52
SEG21
51
SEG22
50
SEG23
49
SEG24 SEG25 SEG26 SEG27
48
SEG9
INT0
72
SEG0
71
SEG1
70
SEG2
69
SEG3
68
SEG4
67
SEG5
66
SEG6
65
SEG7
32
VSS 33
P27 34
P26 35
P25 36
P24 37
P23 38
P22 39
P21 40
P20
P17
42 P16 43 P15 44
KITCHEN
TIMER
CHICKEN
PIECES CHICKEN
BREAST
FROZEN
ROLL FRESH
ROLL
STEAKS/
CHOPS
BAKED
POTATO
FISH/
SEAFOOD
REHEAT
POPCORN
FROZEN
ENTREES
MINUTE
PLUS
START
FRESH
VEGETABLES
GROUND MEAT
(COMPU
DEFROST)
GROUND MEAT
(INSTANT
ACTION)
POWER
LEVEL
AUTO
START
CLOCK
IC-1 IZA931DR
G12
54321 09876
P14
45 46 47 
1VL2 2VL1 3AN7 4AN6 5AN5 6AN4 7AN3 8AN2 9AN1 10AN0 11P57 12P56 13P55 14P54 15P53 16P52 17P51 18P50 19P47 20P46 21P45 22P44 23P43 24
26
P40 25
P41 VL3
VCC

G12
C 2
C 3 C 4 C 5 C 6 C 7 C 8 C 9
VA GND VC INT BUZZER RY1 RY2
NOTE : IF NOT SPECIFIED 1/10w ±5%
DOOR SWITCH
G11 G10
G 9
G 8 G 7 G 6 G 5 G 4 G 3 G 2 G 1
: IF NOT SPECIFIED 1SS355 : IF NOT SPECIFIED 0.01µF / 25v
+
–
C10 47µ/16v
C63 330pF/50v
C62 330pF/50v
C61 330pF/50v
C60 330pF/50v
C20
0.1µ/50v
C12
0.1µ
/50v
C13
0.1µ
/50v
C11 0.1µ/50v
Q10 2SA1037AK
Q11 KRA101S
Q40 KRA101S
Q20 KRA101S
Q22 DTA123JKA
D22 MA152WA
IC2 BA4558
C14
C30
R15 4.7k
R60 15k
CF1
R61 15k
R62 15k
R63 15k
R64 15k
R65 15k
R66 15k
R67 15k
R75 100k
R74 100k
R73 100k
R72 100k
R30 4.7k
R31 15k
LIQUID CRYSTAL DISPLAY
COOK SENSOR LBS KG DEF HELP
KEY UNIT
R80 4.7k (J18)
(J19)
(J20) (Q23)
R71 15k
AH SENSOR
R70 15k R69 15k R68 15k
R10
1k
R11
4.7k
R12
R13 R14 
10k 10k 10k
(J11)
(J13)
(J15)
(J17)
(J21)
(J14) 4.7k
(J16) 4.7k
(J12) 4.7k
(J10) 4.7k
ZD10
UDZ4.3B

STOP
CLEAR

0.015µ/25v
C102
C103 C104
IC2
D101
R101
1.8kF
+
R105
3.32kD
C101
0.1µ/50v
R90
330 1w R112
3.57kD
R104 47k
R113
MA152 WA
R103 10k
R102 360kF
R111 37.4kF R110 75kF R109 150kF R108 300kF R107 620kF R106 47k
F 1 F 2 F 3
C 1