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R305KS

8 – 1

R305KS

Service Manual

 

CHAPTER 8. 

TEST PROCEDURES

[1] Procedure  A : MAGNETRON ASSEMBLY 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. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check across the magnetron filament leads should

indicate less than 1 ohm.

5. To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament leads and chassis ground. This test should indicate

an infinite resistance. If there is little or no resistance the magnetron is grounded and must be replaced.

6. Reconnect all leads removed from components during testing.

7. Reinstall the outer case (cabinet).

8. Reconnect the power supply cord after the outer case is installed.

9. Run the oven and check all functions.

1. MICROWAVE OUTPUT POWER

The following test procedure should be carried out with the microwave oven in a fully assembled condition (outer case fitted).

HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE, SO EXTREME CAUTION SHOULD BE OBSERVED.

Power output of the magnetron can be measured by performing a water temperature rise test. This test should only be used if above tests do not indi-
cate a faulty magnetron and there is no defect in the following components or wiring: silicon rectifier, high voltage capacitor and power transformer.
This test will require a 16 ounce (453cc) measuring cup and an accurate mercury thermometer or thermocouple type temperature tester. For accurate
results, the following procedure must be followed carefully:

1. Fill the measuring cup with 16 oz. (453cc) of tap water and measure the temperature of the water with a thermometer or thermocouple tempera-

ture tester. Stir the thermometer or thermocouple through the water until the temperature stabilizes. Record the temperature of the water.

2. Place the cup of water in the oven. Operate oven at P-HI (100% Power) selecting more than 60 seconds cook time. Allow the water to heat for 60

seconds, measuring with a stop watch, second hand of a watch or the digital read-out countdown.

3. Remove the cup from the oven and again measure the temperature, making sure to stir the thermometer or thermocouple through the water until

the maximum temperature is recorded.

4. Subtract the cold water temperature from the hot water temperature. The normal result should be32.1 to 59.7

°

F(17.9 to 33.2

°

C) rise in tempera-

ture. If the water temperatures are accurately measured and tested for the required time period the test results will indicate if the magnetron tube
has low power output (low rise in water temperature) which would extend cooking time or high power output (high rise in water temperature) which
would reduce cooking time. Because cooking time can be adjusted to compensate for power output, the magnetron tube assembly should be
replaced only if the water temperature rise test indicates a power output well beyond the normal limits. The test is only accurate if the power supply
line voltage is 120 volts and the oven cavity is clean.

[2] Procedure  B : POWER TRANSFORMER 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. Disconnect the primary input terminals and measure the resistance of the transformer with an ohmmeter. Check for continuity of the coils with an

ohmmeter. On the R x 1 scale, the resistance of the primary coil should be less than 1 ohm and the resistance of the high voltage coil should be
approximately 150 ohms (RTRN-A729WRZZ) or 125 ohms (RTRN-A730WRZZ); the resistance of the filament coil should be less than 1 ohm.

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.

(HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO DO NOT ATTEMPT TO MEASURE THE FILAMENT AND HIGH
VOLTAGE.)

[3] Procedure  C : HIGH VOLTAGE RECTIFIER 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. Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance across the terminals and observe, reverse the

leads to the rectifier terminals and observe meter reading. If a short is indicated in both directions, or if an infinite resistance is read in both direc-
tions, the rectifier is probably defective and should be replaced.

5. Reconnect all leads removed from components during testing.

Summary of Contents for R305KS - 1100 Watt 1.1 Cubic Feet Mid Size Microwave

Page 1: ...DURE CHAPTER 12 CIRCUIT DIAGRAMS Parts Guide No S4504R305KPST MICROWAVE OVEN R 305KS SERVICE MANUAL R305KS MODEL CONTENTS SHARP CORPORATION This document has been published to be used for after sales service only The contents are subject to change without notice In the interest of user safety the oven should be restored to its original condition and only parts identical to those specified should b...

Page 2: ...8 3 10 Procedure I NOISE FILTER TEST 8 4 11 Procedure J TOUCH CONTROL PANEL ASSEMBLY TEST 8 4 12 Procedure K KEY UNIT TEST 8 5 13 Procedure L RELAY TEST 8 6 14 Procedure M DEFROST TEST 8 6 15 Procedure N FOIL PATTERN ON THE PRINTED WIRING BOARD TEST 8 6 CHAPTER 9 TOUCH CONTROL PANEL ASSEM BLY 1 OUTLINE OF TOUCH CONTROL PANEL 9 1 2 DESCRIPTION OF LSI 9 1 3 SERVICING FOR TOUCH CONTROL PANEL 9 3 CHAP...

Page 3: ...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 a...

Page 4: ...h voltage capacitor 4 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 2 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 cap...

Page 5: ...he 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 The placing of this standard load in the oven is important not only to protect the oven but also to insure that any leakage is measured accurately 4 Set the cooking control on Full Power Cooking M...

Page 6: ...s 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 personnel 3 DANGER Certain initial parts are intentionally not grounded and present a risk of electrical shock only during servicing Service personnel Do not contact the foll...

Page 7: ...or holding food is less Control Complement Touch Control System Clock 1 00 12 59 Timer 0 99 minutes 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 30 of FULL Power P 30 approx 40 of ...

Page 8: ...have it replaced with a properly grounded three pronged wall receptacle or have a grounding adapter properly grounded and polarized If the extension cord must be used it should be a 3 wire 15 amp or higher rated cord Do not drape over a countertop or table where it can be pulled on by children or tripped over accidentally CAUTION DO NOT UNDER ANY CIRCUMSTANCES CUT OR REMOVE THE ROUND GROUNDING PRO...

Page 9: ...NEL NOTE Some one touch cooking features such as MINUTE PLUS are disabled after three minutes when the oven is not in use These fea tures are automatically enabled when the door is opened and closed or the STOP CLEAR pad is pressed ...

Page 10: ...time still remaining in the cook cycle when the door was opened 7 The monitor switch electrically monitors the operation of the sec ondary interlock switch and primary interlock relay and is mechani cally associated with the door so that it will function in the following sequence a When the door opens from the closed position the primary interlock relay RY2 and secondary interlock switch open thei...

Page 11: ...Y INTERLOCK RELAY GRN B2 CAPACITOR 0 19µF AC 2100V B1 FUSE 20A NOISE SUPPRESSION COIL LINE CROSS CAPACITOR 0 22µF AC 250V LINE BYPASS CAPACITOR 0 0033µF AC 125V LINE BYPASS CAPACITOR 0 0033µF AC 125V L N NOISE FILTER MAGNETRON MAGNETRON OR OR OVEN NOTE indicates components with potentials above 250V 120V AC 60 Hz OVEN LAMP OVEN LAMP RELAY TURN TABLE MOTOR FAN MOTOR POWER TRANSFORMER MONITOR SWITCH...

Page 12: ...R SENSING SWITCH PRIMARY INTERLOCK RELAY RY2 SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OPERATION REFER TO CHAPTER TEST PROCEDURE NOTE MONITOR FUSE AND MONITOR SWITCH ARE REPLACED AS AN ASSEMBLY 4 TURNTABLE MOTOR The turntable motor rotates the turntable located on the bottom of the oven cavity so that the food on the turntable is cooked evenly The turntable may turn in either direct...

Page 13: ...r 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 1 TROUBLESHOOTING CHART RE CK A B C D E F F G H RE RE CK J CK CK CK K L N I POSSIBLE CASE AND DEFECTIVE PARTS SHORT IN POWER CORD SHORT OR OPENED WIRING MAGNETRON POWER TRANSFORMER H V RECTIFIER ASSEMBLY HIGH VOLTAGE CAPACITOR TEMPERATURE FUSE ...

Page 14: ...e to stir the thermometer or thermocouple through the water until the maximum temperature is recorded 4 Subtract the cold water temperature from the hot water temperature The normal result should be32 1 to 59 7 F 17 9 to 33 2 C rise in tempera ture If the water temperatures are accurately measured and tested for the required time period the test results will indicate if the magnetron tube has low ...

Page 15: ... fuse oven or thermal cut out magnetron indicates overheating of the oven exchange the temperature fuse or thermal cut out and check inside of oven cavity and for improper setting of cooking time or operation of control unit Check for restricted air flow through the vent holes of the oven cavity especially the cooling fan and air guide 6 Reconnect all leads removed from components during testing 7...

Page 16: ...ply cord and then remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Before performing this test make sure that the secondary interlock switch and the primary interlock relay are operating properly according to the above Switch Test Procedure Disconnect the wire lead from the monitor switch COM terminal Check the monitor switch operation by using the ohmmeter ...

Page 17: ...nnot be performed with only a voltmeter and ohmmeter In this service manual the touch control panel assembly is divided into two units Control Unit and Key Unit and also the Control Unit is divided into two units CPU Unit and Power Unit and troubleshooting by unit replacement is described according to the symptoms indicated Before testing 1 Disconnect the power supply cord and then remove outer ca...

Page 18: ...ply cord and then remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Reconnect all leads removed from components during testing 5 Re install the outer case cabinet 6 Reconnect the power supply cord after the outer case is installed 7 Run the oven and check all functions 12 Procedure K KEY UNIT TEST 1 Disconnect the power supply cord and then remove outer case ...

Page 19: ... 10 Discharge high voltage capacitor 11 Reconnect all leads removed from components during testing 12 Re install the outer case cabinet 13 Reconnect the power supply cord after the outer case is installed 14 Run the oven and check all functions 14 Procedure M DEFROST TEST WARNING The oven should be fully assembled before following procedure 1 Place one cup of water in the center of the turntable t...

Page 20: ... 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 these leads remain isolated from other components and oven chassis by using insulation tape 6 After that procedure re connect the power supply cord 7 Follow the troubleshooting guide given below for repair 8 Disconnect th...

Page 21: ... frequency 7 Door Sensing Switch A switch to tell the LSI if the door is open or closed 8 Back Light Circuit A circuit to drive the back light Light emitting diodes LD1 LD3 2 DESCRIPTION OF LSI The I O signal of the LSI are deiled in the following table Symbol Voltage Application VSS 5V LSI IC1 Pin No Signal I O Description 1 P50 IN Signal coming from touch key When either G9 line on key matrix is...

Page 22: ...e voltage The power source voltage to drive the A D converter in the LSI 52 P11 IN To input signal which communicates the door open close information to LSI Door close H level signal 0V Door open L level signal 5V 53 P10 OUT Terminal not used 54 P33 OUT Key strobe signal Signal applied to touch key section A pulse signal is input to P50 P51 P52 and P53 terminal while one of G1 line keys on key mat...

Page 23: ...g it connected to the oven b On some models the power supply cord between the touch control panel and the oven proper is so long enough that they may be separated from each other For those models therefore it is possible to check and repair the controls of the touch control panel while keeping it apart from the oven proper in this case you must short both ends of the door sensing switch on PWB of ...

Page 24: ...s adjusted accordingly 3 Soldering As the melting point of lead free solder Sn Ag Cu is higher and has poorer wettability flow 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 flow is achieved The high content of tin in lead free solder will cause premature corrosion of...

Page 25: ...t close firmly 2 Door hinge support or latch hook is damaged 3 The door gasket or seal is damaged 4 The door is bent or warped 5 There are defective parts in the door interlock system 6 There are defective parts in the microwave generating and transmission assembly 7 There is visible damage to the oven Do not operate the oven 1 Without the RF gasket Magnetron 2 If the wave guide or oven cavity are...

Page 26: ...r to PICTORIAL DIAGRAM 4 Reinstall outer case and check that oven is operating properly 4 HIGH VOLTAGE COMPONENTS REMOVAL HIGH VOLTAGE CAPACITOR AND HIGH VOLT AGE RECTIFIER ASSEMBLY To remove the components proceed as follows 1 Disconnect the power supply cord and remove outer case 2 Open the oven door and block it open 3 Discharge high voltage capacitor 4 Disconnect the high voltage wire of the p...

Page 27: ...D holder and the rubber connector from the control panel frame 7 Tear away the graphic sheet from the control panel frame 8 Tear away the membrane switch from the control panel frame 2 REINSTALLATION 1 Remove remaining adhesive on the control panel frame surfaces with a soft cloth soaked in alcohol 2 Tear the backing paper from the new membrane switch 3 Insert the ribbon cable of the membrane swit...

Page 28: ...cavity back plate 6 Remove the fan blade from the fan motor shaft according to the fol lowing procedure 7 Hold the edge of the rotor of the fan motor by using a pair of groove joint pliers CAUTION Make sure that no metal pieces enter the gap between the rotor and the stator of the fan motor because the rotor is easily shaven by pliers and metal pieces may be produced Do not touch the pliers to the...

Page 29: ...d into the square hole of the rear cabinet referring to the Figure C 3 b 2 Install the earth wire lead of power supply cord to the oven cavity back plate with one 1 screw and tight the screw 3 Connect the gray wire leads of power supply cord to the noise filter correctly referring to the Pictorial Diagram 4 Re install outer case and check that the oven is operating properly Figure C 3 b Power Supp...

Page 30: ...y of door remains less than 0 5mm when in the latched position First check upper position of latch hook pushing and pulling upper portion of door toward the oven face Then check lower portion of the latch hook pushing and pulling lower portion of the door toward the oven face Both results play in the door should be less than 0 5mm 2 The door sensing switch and secondary interlock switch interrupt ...

Page 31: ...smoothly catch latch hook through latch holes and that latch head goes through center of latch hole 2 Deviation of door alignment from horizontal line of cavity face plate is to be less than 1 0mm 3 Door is positioned with its face pressed toward cavity face plate 4 Check for microwave leakage around door with an approved micro wave survey meter Refer to Microwave Measurement Procedure NOTE The do...

Page 32: ...WER TRANSFORMER COM NO GRY W H T WHT GRY RED GRY GRY R E D P N K B L K W H T R E D GRN GRY GRY GRN BLK GRY WHT GRY RED RED GRN BLK PNK GRY C T FUSE FUSE NOISE FILTER FAN MOTOR BLK WHT 2 1 WHT WHT WHT RED RY1 PRIMARY INTERLOCK RELAY CN B CN B T1 1 2 N O COM RY2 N O COM CONTROL UNIT GRY OVEN LAMP PNK RED RED PNK RED WHT Power Supply Cord Screw Oven Cavity Back Plate L N Connect the wire lead which h...

Page 33: ... G 7 SE G 8 SE G 9 SEG 10 SEG 11 SEG 12 COM3 COM2 COM1 B 1 DOOR R S T 5V INT B Z C OM M C 40 G ND R 1 560 1 2W C N B AC H AC N AC 120V 60HZ G 6 G 7 G 8 G 3 J 1 DT A123J S G 10 G 11 G 12 G 4 G 5 G 9 V R R 30 3 3K 0 01uF 25V C OM1 C OM2 C OM3 S E G 1 S E G 2 S E G 3 S E G 4 S E G 5 S E G 6 P 71 P 72 AV DD P 01 P 00 R E S E T X2 X1 V S S V DD XT 2 XT 1 IC P 53 P 52 P 51 P 50 P 02 B L 17 G 2 G 1 SEG 1...

Page 34: ...R305KS 12 3 3 Printed Wiring Board of Power Unit Figure S 3 Figure S 3 Printed Wiring Board of Power Unit ...

Page 35: ...mation 1 MODEL NUMBER 2 REF NO 3 PART NO 4 DESCRIPTION Parts marked may cause undue microwave exposure Parts marked are used in voltage more than 250V DOOR PROTECTION SHEET SPADPA204WRE0 TOP PAD ASSEMBLY FPADBA593WRKZ PLASTIC BAG SSAKHA034WRE0 Not replaceable items PACKING CASE FPAK A541WRKZ BOTTOM PAD ASSEMBLY FPADBA594WRKZ FOAM SHEET SPAKHA012WREZ INTO THE OVEN CAVITY TRAY PAD ASSY CPADBA317WRKZ...

Page 36: ...12 2 1 7 1 1 13 1 2 1 7 7 3 1 10 1 9 4 10 7 10 7 10 7 8 4 11 7 5 4 17 7 4 7 10 1 5 1 4 4 2 1 1 1 1 1 11 7 7 7 10 7 10 7 7 6 3 7 10 7 9 7 2 7 2 7 10 7 10 7 10 7 6 1 12 7 8 4 8 1 8 7 10 7 8 1 2 2 3 2 2 4 12 4 6 4 14 7 1 1 3 4 16 4 15 1 6 7 1 6 1 6 2 6 5 4 7 2 3 2 3 4 12 2 3 ...

Page 37: ...mer Interchangeable for production 1 11 RV MZA288WRE0 BK Magnetron 1 11 RV MZA321WRZZ BH Magnetron Interchangeable 1 11 RV MZA340WRZZ Magnetron Interchangeable for production use 1 12 QFS TA014WRE0 AG Temperature fuse 150deg C Magnetron 1 12 RTHM A119WRE0 AK Thermal cut out 145C Magnetron Interchangeable 1 13 FPWBFA385WRKZ AV Noise filter assembly CABINET PARTS 2 1 GCABUA935WRPZ BD Outer case cabi...

Page 38: ...R305KS 4 2 DOOR AND CONTROL PANEL PARTS 3 2 6 7 3 3 3 5 3 7 3 8 3 2 1 3 2 4 3 2 2 3 2 5 3 4 3 1 3 6 3 2 6 6 6 5 1 5 3 3 2 3 5 2 5 4 5 9 5 5 5 7 5 6 5 8 ...

Page 39: ...DIA142WRRZ AG Display window 3 4 LHLD A262WRFZ AF LCD holder 3 5 PSHEPB021WREZ AQ LED SHEET 3 6 QCNC A019WRZZ AG Rubber connector 3 7 RLCDSA108DRZZ AU Liquid crystal display 3 8 XEPS730P08XS0 AA Screw 3mm x 8mm DOOR PARTS 5 1 FDORFA364WRTZ AS Door panel 5 2 PSHEPA382WRE0 AH Sealer film 5 3 GWAKPA998WRFZ AX Door frame 5 4 HPNL A841WRRZ AU Door screen 5 5 LSTPPA188WRF0 AG Latch head 5 6 MSPRTA187WRE...

Page 40: ...AK PCUSGA399WRE0 1 4 11 AF PCUSGA614WRPZ 1 4 14 AE PCUSGA615WRPZ 1 4 15 AE PCUSGA616WRPZ 1 4 17 AK PCUSGA620WRPZ 1 4 6 AF PCUSUA235WRP0 1 4 13 AE PCUSUA278WRP0 1 4 12 AB PDUC A832WRWZ 1 4 9 AP PDUC A833WRPZ 1 4 8 AM PHOK A131WRFZ 1 4 1 AL PPACGA176WREZ 1 4 10 AC PSHEPA382WRE0 2 5 2 AH PSHEPB021WREZ 2 3 5 AQ PSHEPB114WREZ 2 3 2 5 Q QCNC A019WRZZ 2 3 6 AG QFS TA014WRE0 1 1 7 AG 1 1 12 AG QSW KA055DR...

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