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R-890SLM

S3905R890PKS

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

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CHAPTER 1. BEFORE SERVICING
CHAPTER 2. WARNING TO SERVICE PERSONNEL
CHAPTER 3. PRODUCT SPECIFICATIONS
[1]   SPECIFICATION .........................................3-1

CHAPTER 4. APPEARANCE VIEW
CHAPTER 5. OPERATION SEQUENCE
[1]   OFF CONDITION ........................................5-1
[2]   MICROWAVE COOKING CONDITION .......5-1
[3]   GRILL COOKING CONDITION ...................5-2
[4]   CONVECTION COOKING CONDITION .....5-2
[5]   COMBI COOKING CONDITION ..................5-2
[6]   ON/OFF TIME RATIO ..................................5-3
[7]   AUTO POWER CONTROL OPERATION ....5-3

PONENTS
[1]   DOOR OPEN MECHANISM ........................6-1
[2]   SWITCH ......................................................6-1
[3]   FUSE ...........................................................6-1
[4]   TC TRANSFORMER ...................................6-1
[5]   THERMAL CUT-OUT ...................................6-1
[6]   ASYMMETRIC RECTIFIER .........................6-1
[7]   NOISE FILTER ............................................6-2
[8]   MOTOR .......................................................6-2
[9]   HEATING ELEMENT ...................................6-2
[10]  CONVECTION COOKING SYSTEM ...........6-2
[11]  FIRE SENSING FEATURE ..........................6-2
[12]  OPEN JUDGE BY THERMISTOR ...............6-2

CHAPTER 7. TROUBLESHOOTING GUIDE
CHAPTER 8. TEST PROCEDURES
[1]   A: MAGNETRON TEST ...............................8-1
[2]   B: HIGH VOLTAGE TRANSFORMER
 

TEST ...........................................................8-1

[3]   C: HIGH VOLTAGE RECTIFIER TEST .......8-2
[4]   D: HIGH VOLTAGE CAPACITOR TEST ......8-2
[5]   E: SWITCH TEST ........................................8-2
[6]   F: THERMISTOR TEST ...............................8-2
[7]   G: THERMAL CUT-OUT TEST ....................8-3
[8]   H: MOTOR WINDING TEST. .......................8-3
[9]   I: NOISE FILTER TEST ...............................8-3
[10]  J: BLOWN FUSE (F1) 20A ..........................8-3
[11]  K: BLOWN FUSE F8A .................................8-3
[12]  L: GRILL HEATING ELEMENTS (TOP)
 

AND BOTTOM HEATING ELEMENT

 

TEST ...........................................................8-4

[13]  M: CONTROL PANEL ASSEMBLY TEST ....8-4
[14]  N: JOG SWITCH UNIT TEST ......................8-4

[15]  O: RELAY TEST ..........................................8-5
[16]  P: PROCEDURES TO BE TAKEN
 

WHEN THE FOIL PATTERN ON THE

 

PRINTED WIRING BOARD (PWB) IS

 

OPEN ..........................................................8-5

CHAPTER 9. CONTROL PANEL ASSEMBLY
[1]   OUTLINE OF CONTROL PANEL ................9-1
[2]   SERVICING FOR CONTROL PANEL .........9-2

ADJUSTMENT PROCEDURE
[1]   BEFORE OPERATING ................................11-1
[2]   OUTER CASE CABINET REMOVAL ..........11-1
[3]   HIGH VOLTAGE COMPONENTS 
 

REMOVAL ...................................................11-2

[4]   HIGH VOLTAGE TRANSFORMER 
 

REMOVAL ...................................................11-2

[5]   MAGNETRON REMOVAL ...........................11-2
[6]   FAN MOTOR REPLACEMENT ...................11-2
[7]   TURNTABLE MOTOR REPLACEMENT .....11-3
[8]   CONVECTION FAN MOTOR REMOVAL ....11-3
[9]   POSITIVE LOCK CONNECTOR 
 

REMOVAL ...................................................11-4

[10]  OVEN LAMP REMOVAL .............................11-4
[11]  POWER SUPPLY CORD REPLACE-
 

MENT ..........................................................11-4

[12]  TOP HEATING ELEMENTS REMOVAL ......11-4
[13]  BOTTOM HEATING ELEMENTS 
 

REMOVAL ...................................................11-5

[14]  CONTROL PANEL ASSEMBLY REMOVAL ....11-5
[15]  MONITORED LATCH SWITCH, MONITOR
 

SWITCH AND STOP SWITCH REMOVAL .....11-5

[16]  MONITORED LATCH SWITCH, STOP SWITCH
 

AND MONITOR SWITCH ADJUSTMENT ......11-5

[17]  DOOR REPLACEMENT ..............................11-6

CHAPTER 12. MICROWAVE MEASUREMENT
CHAPTER 13. CIRCUIT DIAGRAMS
[1]   Oven Schematic ..........................................13-1
[2]   Pictorial Diagram (Figure S-1) .....................13-6
[3]   Control Unit Circuit ......................................13-7
[4]   Printed Wiring Board of Control Unit ...........13-8
[5]   Printed Wiring Board of Power Unit .............13-9
[6]   Printed Wiring Board of Switch Unit ............13-10

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R-890SLM

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.

THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:

GREEN-AND-YELLOW ------------------------------- EARTH
BLUE -------------------------------------------------- NEUTRAL
BROWN -------------------------------------------------------LIVE

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.

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 "S" on parts list are used at voltage more than 250V.
Removal of the outer wrap gives access to potential 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 Convection heater with the oven outer cabinet removed. (Because air flow is elimi-

nated, and the excess heat generated on adjacent components). 

1 - 1

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R-890SLM

Microwave ovens contain circuitry capable of producing very high voltage and current, contact with any part of the high voltage circuit 

will result in electrocution. High voltage capacitor, Power transformer, Magnetron, High voltage rectifier assembly, High voltage fuse, 

High voltage harness.

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  level  to  HIGH  (100%). And  set  the  microwave 

timer for two (2) minutes. When the two minutes has elapsed 

(timer at zero) carefully check that the water is now hot. If the 

water remains cold, carry out 3D checks and re-examine the 

connections to the component being tested. 

When all service work is completed and the oven is fully assembled, the microwave power output should be checked and microwave 

leakage test should be carried out.

2 - 1

1)  Disconnect the supply.
2)  Door opened, and wedged open.
3)  Discharge the high voltage capacitor.

Sharp recommend that wherever possible fault-finding is 

carried out with the supply disconnected. It may, in some 

cases, be necessary to connect the supply after the outer 

case has been removed, in this event carry out 3D checks 

and then disconnect the leads to the primary of the power 

transformer. Ensure that these leads remain isolated from 

other components and the oven chassis. (Use insulation tape 

if necessary.) When the testing is completed, carry out 3D 

checks and reconnect the leads to the primary of the power 

transformer.

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