Sharp R-7500AT User manual

R-7500AT
1
CONTENTS
BEFORE SERVICING -----------------------------------------------------------------2
WARNING TO SERVICE PERSONNEL-----------------------------------------------------3
PRECAUTIONS FOR USING LEAD-FREE SOLDER -------------------------------------------4
PRODUCT SPECIFICATIONS -----------------------------------------------------------5
GENERAL INFORMATION--------------------------------------------------------------6
TEST PROCEDURES -----------------------------------------------------------------7
WIRING ---------------------------------------------------------------------------9
CIRUITS--------------------------------------------------------------------------23
TROUBLESHOOTING ----------------------------------------------------------------27
TEST MODE AND INPUT CURRENT ADJUSTMENT ------------------------------------------33
SERVICE COUNTERS----------------------------------------------------------------36
COMPONENT REPLACEMENTAND ADJUSTMENT PROCEDURE -------------------------------39
SERVICE INFORMATION -------------------------------------------------------------63
MICROWAVE MEASUREMENT ---------------------------------------------------------63
SERVICE MANUAL
S5902R7500PH/T
COMMERCIAL
MICROWAVE OVEN
R-7500AT
In interests of user-safety the oven should be restored to its original condition and only parts identical to those specied
should be used.
This document has been published to be used for after sales service only.
The contents are subject to change without notice.
MODEL

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R-7500AT
BEFORE SERVICING
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 qualied to render satisfactory
customer service.
WARNING: THIS APPLIANCE MUST BE EARTHED
IMPORTANT
THE WIRES IN THIS MAINS LEADARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:
GREEN-AND-YELLOW---------------EARTH
BLUE-----------------------------------NEUTRAL
BROWN-------------------------------------- LIVE
CAUTION MICROWAVE RADIATION
DO NOT BECOME EXPOSED TO RADIATION FROM THE MICROWAVE GENERATOR OR OTHER PARTS CON-
DUCTING MICROWAVE ENERGY.
Service engineers should not be exposed to the microwave energy which may radiate from the magnetron or other microwave gen-
erating devices if it is improperly used or connected. All input and output microwave connections, waveguides, anges 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.
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 guide are used at voltage more than 250V.
Removal of the outer wrap gives access to potential above 250V.
All the parts marked "*" on parts guide may cause undue microwave exposure, by themselves, or when they are damaged, loosened
or removed.

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WARNING TO SERVICE PERSONNEL
The ovens contain circuitry capable of producing very high voltage and current, con-
tact with following parts may result in a severe, possibly fatal, electrical shock.
(Example)
Inverter unit, Magnetron, High Voltage Harness etc..
Read the Service Manual carefully and follow all instructions.
BEFORE SERVICING
1. Disconnect the power supply cord, and then remove the outer case cabinet and the back plate assembly.
2. Open the door and block it open.
3. Wait for 60 seconds to discharge the high voltage capacitors of the inverter unit.
4. Disconnect the high voltage wire from the magnetron terminal with insulated pliers.
5. Make the terminal (metal part) of the high voltage wire contact to the magnetron body with insulated pliers.
6. Now, the capacitors of the inverter unit are discharged.
7. Reconnect the high voltage wire to the magnetron terminal after discharging.
WARNING: Use the pliers that the portions of their handles are insulated completely to avoid an electric shock.
WARNING: RISK OF ELECTRIC SHOCK. DISCHARGE THE HIGH-VOLTAGE CAPACITOR BEFORE SERVICING.
The high-voltage capacitor remains charged about 60 seconds after the oven has been switched off. Wait for 60 seconds.
Whenever troubleshooting is performed the power supply must be disconnected. It may, in some cases, be necessary to connect the
power supply after the outer case cabinet has been removed, in this event,
1. Disconnect the power supply cord, and then remove the outer case cabinet and the back plate assembly.
2. Open the door and block it open.
3. Wait for 60 seconds to discharge the high voltage capacitors of the inverter unit.
4. Disconnect the high voltage wire from the magnetron terminal with insulated pliers.
5. Make the terminal (metal part) of the high voltage wire contact to the magnetron body with insulated pliers.
6. Now, the capacitors of the inverter unit are discharged.
7. Reconnect the high voltage wire to the magnetron terminal after discharging.
WARNING: Use the pliers that the portions of their handles are insulated completely to avoid an electric shock.
8. Disconnect the inverter harness from the main harness.
9. Ensure that the leads remain isolated from other components and oven chassis by using insulation tape.
10. After that procedure, reconnect the power supply cord.
WHEN THE TESTING IS COMPLETED
1. Disconnect the power supply cord, and then remove the outer case cabinet and the back plate assembly.
2. Open the door and block it open.
3. Wait for 60 seconds to discharge the high voltage capacitors of the inverter unit.
4. Disconnect the high voltage wire from the magnetron terminal with insulated pliers.
5. Make the terminal (metal part) of the high voltage wire contact to the magnetron body with insulated pliers.
6. Now, the capacitors of the inverter unit are discharged.
7. Reconnect the high voltage wire to the magnetron terminal after discharging.
WARNING: Use the pliers that the portions of their handles are insulated completely to avoid an electric shock.
8. Reconnect all leads removed from components during testing.
9. Reinstall the outer case cabinet and the back plate assembly.
10. Reconnect the power supply cord after the outer case cabinet and the back plate assembly are installed.
11. Run the oven and check all function.
AFTER REPAIRING
1. Reconnect all leads removed from components during testing.
2. Reinstall the outer case cabinet (cabinet) and the back plate assembly.
3. Reconnect the power supply cord after the outer case cabinet and the back plate assembly are installed.
4. Run the oven and check all functions.
Don't Touch !
Danger High Voltage

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R-7500AT
PRECAUTIONS FOR USING LEAD-FREE SOLDER
Employing lead-free solder
The "Main PWB" of this model employs lead-free solder. This is indicated by the "LF" symbol printed on the PWB and in the service
manual. The sufx letter indicates the alloy type of the solder.
Example:
Indicates lead-free solder of tin, silver and copper Indicates lead-free solder of tin, copper and nickel
Using lead-free wire solder
When repairing a PWB with the "LF" symbol, only lead-free solder should be used. (Using normal tin/lead alloy solder may result in
cold soldered joints and damage to printed patterns.)
As the melting point of lead-free solder is approximately 40ºC higher than tin/lead alloy solder, it is recommend that a dedicated bit is
used, and that the iron temperature is adjusted accordingly.
Soldering
As the melting point of lead-free solder (Sn-Ag-Cu, Sn-Cu-Ni) is higher and has poorer wettability, (ow), to prevent damage to the
land of the PWB, extreme care should be taken not to leave the bit in contact with the PWB for an extended period of time. Remove
the bit as soon as a good ow is achieved. The high content of tin in lead free solder will cause premature corrosion of the bit. To re-
duce wear on the bit, reduce the temperature or turn off the iron when it is not required.
Leaving different types of solder on the bit will cause contamination of the different alloys, which will alter their characteristics, mak-
ing good soldering more difcult. It will be necessary to clean and replace bits more often when using lead-free solder. To reduce bit
wear, care should be taken to clean the bit thoroughly after each use.
Oven should not be run empty. To test for the presence of microwave energy within a cavity, place a cup of cold water on the ceram-
ic oven oor, close the door and set the power to 100% and set the microwave timer for one (1) minute. When the one minute has
elapsed (timer at zero) carefully check that the water is now hot. If the water remains cold carry out Before Servicing procedure 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.
BEFORE REPLACING THE PRINTED WIRING BOARD
Some normal boards are found in board units that have been returned due to oven failure. So, most of board replacements may arise
from poor harness connection. Accordingly, before replacing any board that was judged to require its replacement, use the following
procedure to re-check that the connection terminal of a connector has been properly inserted:
1. When the connectors have been incorrectly inserted to the control unit.
CONNECTOR Symptom
CN-A The oven can not be powered on.Antenna motor(s) does not run.Blower motor(s) does not run.
CN-B The oven can not be powered on.No heating can be done.LED light does not illuminate.
CN-D,CN-F No indication, no key insertion and no buzzer sound.
CN-G The power level can not be varied.MGT thermistor(s) does not work.Magnetron(s) does not work.ER-
ROR(s) shows.
2. When latch switch adjustment is incorrect
When latch switch adjustment is incorrect, symptoms such as no heating, no heating start, no activation even with start button
pressed, etc. will occur.

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PRODUCT SPECIFICATIONS
* This Product fulfils the requirement of the EuropeanAC Line Voltage................... Single phase 230V, 50 Hz
AC Power Required............. 2.85 kW 12.2Ａ
Output Power....................... 1800 W (IEC 60705)
Sound level.......................... less than 70dB (A)
Outside Dimensions............ 420(W) x 337(H) x 480(D) mm
Microwave Frequency.......... 2450 MHz* (Group 2 / Class B)
standard EN55011. In conformity with this standard,
this product is classified as group 2 class B equipment.
Group 2 means that the equipment intentionally
generates radio-frequency energy in the form of
electromagnetic radiation for heating treatment of food.
Class B equipment means that the equipment suitable
to be used in domestic establishments.
This product is designed for commercial application
only and as such it falls outside the scope of R
egulation
(EC) 1275/2008 implementing EU Directiv
e 2005/32/EC
on eco-design requirements for standby and off mode
electric power consumption.Sharp do not recommend
the product for domestic application and will not accept
any liability for such use.
(Single)
420(W) x 674(H) x 480(D) mm
(Two ovens stacked)
Cavity Dimensions............... 332(W) x 171.5(H) x 330(D) mm
Oven Capacity.....................19 litres
Weight ................................. Approx. 20kg
Cooking Uniformity.............. Rotary antenna system
•
As part of a policy of continuous improvement, we reserve
the right to alter design and specification without notice.
N
OTE: External Equipotential EarthingTerminal
E
quipment has secondary earthing terminal.
T
erminal provides external earthing connection
u
sed in addition to earthing prong on plug. Located on
ou
tside of oven back, terminal is marked with symbol
shown on the right side.
SPECIFICATIONS
COMMERCIAL MICROWAVE OVEN Equipotential marking OTHER COMMERCIAL
ELECTRICAL APPLIANCE
Washer
Lead wire
Screw
Equipotential earthing
terminal
Lead wire
Earth angle
(Equipotential earthing terminal)
Fig. A-1
INSTALLATION INFORMATION
When this commercial microwave oven is installed near other commercial electrical appliances, connect a lead wire
to each equivalent potential terminal with equipotential marking between them (insert a lead wire between a washer
and an earth angle, and screw them), as shown in Fig. A-1, to make sure that they are at equivalent potential.
If any lead wire is not connected between them, when person touch them he/she will get a electric shock.

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R-7500AT
GENERAL INFORMATION
OVEN DIAGRAM
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OVEN
1. Control panel
2. Door latch openings
3. Ceramic shelf
4. Splash cover
5. Oven lamp
6. Door hinges
7. Door (glass)
8. Door latches
9. Door handle
10. Door seals and sealing surfaces
11. Air intake filter (air intake openings)
12. Filter knob
13. Outer cabinet
14. Ventilation openings
15. Power supply cord
16. Mounting plate
17. Screw for mounting plate
OPERATING PADS
3.SET MEMORY pad
4.POWER LEVEL pad
5.Ten number pads
6.DOUBLE QUANTITY pad
7. TRIPLE QUANTITY pad
8.STOP/CLEAR pad
9.START pad
CONTROL PANEL
PART NAMES
9
7
1
2345
6
8
10 11 12
13
14
15
16
17
1 2 3 4 5 67 8 9
DISPLAY INFORMATION
MEMORY : MEMORY will appear when saving, checking
or deleting memory programs. It is also shown
during Program Lock, Oven Lamp or Audible
Signal Sound setting.
MENU : MENU will appear when selecting memory
number.
POWER : POWER will appear when selecting microwave
power level.
X2, X3 : X2 or X3 will appear when selecting double or
triple quantity.
CLEAN CAUTION : CLEAN CAUTION will appear when
the cleaning of the air intake filter should be
necessary.
HOT: HOT will appear when the oven is very hot.
1.Memory number/Power level indicator
2.Cooking stage indicators
Check to make sure the following accessories are provided:
• Operation manual
• Touch guide
• Caution sheet
(SPECIAL INSTRUCTIONS AND WARNINGS)
ACCESSORIES
NOTE:
• When you order accessories, please mention the two
items: part name and model name to your dealer or
SHARP authorized service agent.
• The model name is printed on the door of the microwave
oven.
R-7500M [EN].indd Sec3:7 2019/02/01 17:23:53

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TEST PROCEDURES
[1] INTERLOCK SWITCH -1 AND/OR -2 TEST
1.Disconnect the power supply cord, and then remove outer case.
2.Open the door full assy and block it open.
3.Wait for 60 seconds to discharge the high voltuge capacitor of the inverter unit.
4.Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal
of the switch. The meter should indicate an open circuit with the door open and a closed circuit with
the door closed. If improper operation is indicated, replace the secondary interlock 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 are installed.
8.Run the oven and check all functions.
[2] INTERLOCK SYSTEM TEST
1. DOOR SENSING SWITCH
1.Disconnect the power supply cord, and then remove outer case.
2.Open the door full assy and block it open.
3.Wait for 60 seconds to discharge the high voltuge capacitor of the inverter unit.
4. Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal
of the switch. The meter should indicate an open circuit with the door open and a closed circuit with
the door closed. If improper operation is indicated, replace the door sensing 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 are installed.
8. Run the oven and check all functions.
2. INTERLOCK RELAY RY1
1.Disconnect the power supply cord, and then remove outer case .
2.Open the door full assy and block it open.
3.Wait for 60 seconds to discharge the high voltuge capacitor of the inverter unit.
4.Disconnect two (2) wire leads from the male tab terminals of the Interlock Relay RY1. Check
the state of the relay contacts using a ohmmeter. The relay contacts should be open. If the relay
contacts are closed, replace the circuit board entirely .
5.Reconnect all leads removed from components during testing.

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R-7500AT
6.Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case are installed.
8. Run the oven and check all functions.
[3] G: MONITOR SWITCH -1 AND/OR -2 TEST
1.Disconnect the power supply cord, and then remove outer case and rear cabinet.
2.Open the door full and block it open.
3.Wait for 60 seconds to discharge the high voltuge capacitor of the inverter unit.
4.Before performing this test, make sure that the interlock switches -1, -2 and the interlock relay RY1
are operating properly, according to the above Switch Test Procedure. Disconnect the wire lead from
the monitor switches -1, -2 (COM) terminals. Check the monitor switches -1, -2 operation by using
the ohmmeter as follows. When the door is open, the meter should indicate a closed circuit. When
the monitor switch actuator is pushed by a screw driver through the upper latch hole on the front plate
of the oven cavity with the door opened (in this condition the plunger of the monitor switch is pushed in),
the meter should indicate an open circuit. If improper operation is indicated, the switch may be defective.
After testing the monitor switches, reconnect the wire lead to the monitor switch (COM) terminals and
check the continuity of the monitor circuit.
5.Reconnect all leads removed from components during testing.
6.Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the rear cover and the outer case are installed.
8. Run the oven and check all functions.
Screw Driver
Ohmmeter
Monitor switch -2
Latch hook
Monitor switch -1

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WIRING
●Power supply cord
●Noise  lter unit and Fuses F10A
Brown wire Power supply cord
Green/Yellow wire
Screw
Blue wire
Noise filter unit
Blue・Red
(Blue case)
Red
Fuse-1
Noise filter unit
Red・Red
(Blue case) Red・Red
Fuse-2
White
Red・Red

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Green
White
Door sensing switch
Monitor switch-1
(Cabinet side)
COM:Red
NO:Blue・White
NC:Gray・Black
COM: Red
NC:Gray
Cabinet side
COM:Red
NC:White
Monitor switch-2
(Oven side)
Oven side
Oven side
Cabinet side
Oven side
NO:Gray・Blue
Oven side
COM: Gray・Red
●Latch switches
Cabinet side
Interlock switch-2
(Oven side)
Interlock switch-1
(Cabinet side)
Cabinet side
Cabinet side

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Red・White
CNB
Control harness
Connector CND
CNA
●Relay unit
Relay unit
Control harness
Connector
Main harness
Oven side:Blue
Main harness
Cabinet side:
Main harness
Connector
●Power unit
Control harness：Green・Blue
Bottom plate
sub assy
Power unit CN1
No3: Gray
No1：Red
CN21
No1:Green
Earth wire of power unit:
Green
No2:Red

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●Wiring to Relay and motor harness
●Control unit
Current transformer
CT1
Motor
harness
Wire lead to Relay
：
Blue
Ribbon cable of FPC
Control unit
Connector CNF of
control harness
Connector CNG of
control harness

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●Wiring to Relay and motor harness
●Control unit
Current transformer
CT1
Motor
harness
Wire lead to Relay
：
Blue
Ribbon cable of FPC
Control unit
Connector CNF of
control harness
Connector CNG of
control harness
●Inverter unit
FA: HV wire assy Red F: HV wire assy Red (with case) CN-A:
PWM
harness
No.1: Red
No.2: White
No.3: Blue
AC:
Inverter
harness
Blue
M: Inverter harness Red
Inverter
unit
Heat sink
Printed
wiring
board
Warning: Disconnect power supply before servicing.
The inverter unit contain circuitry capable of producing very high
voltage and current, contact with the heat sinks, FA terminal,
F terminal, printed wiring board and other portions may result in
a severe, possibly fatal, electrical shock.
Magnetron -2
Inverter unit -1
Inverter unit -2
Magnetron -1
Both of Magnetron-1 and Magnetron-2
FA terminal(back plate side): Red(with white case)
F terminal(cavity assy side): Red(with blue case)
Warning: Disconnect power supply before servicing.
●Magnetron

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Magnetron-1
Rear duct
Control harness Connector Connector of MGT
thermistor-1
（Wiring inside the tape at rear side)
Rear duct
Connector of MGT
thermistor-1
Connector of control harness
（Wiring of connection at rear side）
●Wiring to MGT thermistor-1
①Connect the connector of MGT thermistor-1 to the connector of the control harness.
②Insert the connected connectors into the hole of the rear duct.
③Put the cloth tape on the portion where the connectors are inserted at the rear duct.

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Magnetron-1
Rear duct
Control harness Cloth tape
（Wiring with tape at rear side)
Red・Red
White・Gray Blower motor-1
●Blower motor-1

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●Blower motor-2
Gray
Blower motor-2
Red

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●Antenna motor-2
●Antenna motor-1
Antenna motor -2
Cavity assy top plate
Blue
・
White
Red・Red
Antenna motor -1
Motor harness:Gray
Motor harness:Red
Wiring(Antenna motor)

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●Exhaust thermistor
●Exhaust temp. fuse 120℃
Main harness
Exhaust duct AControl harness
Exhaust thermistor
Inverter harness
LED Light
Cavity assy (Left side)
PWM harness
Exhaust temp. fuse 120℃
Exhaust duct A
Gray
Main
harness
Control harness
Harness of exhaust
thermistor
Gray
Gray

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Blower motor-2
Wire holder
Exhaust duct A
Wire holder
Cavity assy
（Left side）
●Positions of wire holders
・At the following eight(8) positions, hold the wire leads with wire holders so that the wire
leads do not touch to any sharp edges.

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Wire holder
Exhaust duct AAntenna motor-2
Cavity assy (Top side)
Wire holder
Wire holder
Wire holder
Wire holder
Separate angle
Screw
Inverter cover R
HV wire assy