Sharp R-307KW Service Manual - Page 17

R307KW

8 – 4

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-BA037WRKZ, even if the monitor switch operates normally. The monitor fuse and monitor switch assembly is

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.

[10] Procedure I: NOISE FILTER 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 lead wires from the terminal the noise filter. Using an ohmmeter, check between

the terminals as described in the following table. If incorrect reading are obtained, replace the

noise filter.

5.


6.

Reinstall the outer case (cabinet).

7.


8.


[11] Procedure J: TOUCH CONTROL PANEL ASSEMBLY TEST

The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike conventional microwave ovens, proper

maintenance cannot 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 troubleshooting by unit replacement

is described according to the symptoms indicated.

Before testing,

1)

Disconnect the power supply cord and then remove outer case.

2)


3)


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.

1. Key Unit

NOTE:

1)

Check key unit ribbon connection before replacement.

2)

)Re-install the outer case (cabinet).

3)


4)


The following symptoms indicate a defective key unit.

a)

When touching the pads, a certain pad produces no signal at all.

b)

When touching a number pad, two figures or more are displayed.

c)

When touching the pads, sometimes a pad produces no signal.

If the key unit is defective.

1)

Disconnect the power supply cord and then remove outer case.

2)


3)


4)

Replace the key unit.

5)


6)

Re-install the outer case (cabinet).

MEASURING POINT

INDICATION OF OHMMETER

Between N and L

Open circuit.

Between terminal N and WHITE

Short circuit.

Between terminal L and RED

Short circuit.

FUSE 20A

NOISE FILTER

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

RED

WHITE

N

Section	Page
PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY	3
WARNING TO SERVICE PERSONNEL	4
[1] Before Servicing	4
[2] When the testing is completed,	4
[3] After repairing	4
MICROWAVE MEASUREMENT PROCEDURE	5
[1] Requirements:	5
[2] Preparation for testing:	5
[3] Leakage test:	5
FOREWORD AND WARNING	6
[1] FOREWORD	6
[2] WARNING	6
[3] DANGER	6
PRODUCT DESCRIPTION	7
[1] SPECIFICATIONS	7
GENERAL INFORMATION	8
[1] GROUNDING INSTRUCTIONS	8
[2] OVEN DIAGRAM	8
1. OVEN	8
2. TOUCH CONTROL PANEL	9
OPERATION	10
[1] DESCRIPTION OF OPERATING SEQUENCE	10
1. OFF CONDITION	10
2. COOKING CONDITION	10
3. POWER LEVEL P-0 TO P-90 COOKING	10
4. POWER OUTPUT REDUCTION	10
[2] OVEN SCHEMATIC	11
1. Off Condition	11
2. Cooking Condition	11
[3] DESCRIPTION AND FUNCTION OF COMPONENTS	12
1. DOOR OPEN MECHANISM	12
2. DOOR SENSING AND SECONDARY INTERLOCK SWITCHES	12
3. MONITOR SWITCH	12
4. TURNTABLE MOTOR	12
5. COOLING FAN MOTOR	12
6. TEMPERATURE FUSE (MAGNETRON)	12
7. THERMAL CUT-OUT (OVEN)	12
8. TEMPERATURE FUSE (OVEN)	12
9. MONITOR FUSE	12
10. NOISE FILER	12
TROUBLESHOOTING GUIDE	13
[1] TROUBLESHOOTING CHART	13
TEST PROCEDURES	14
[1] Procedure A: MAGNETRON ASSEMBLY TEST	14
1. MICROWAVE OUTPUT POWER	14
[2] Procedure B: POWER TRANSFORMER TEST	14
[3] Procedure C: HIGH VOLTAGE RECTIFIER TEST	14
[4] Procedure D: HIGH VOLTAGE CAPACITOR TEST	15
[5] Procedure E: TEMPERATURE FUSE OR THERMAL CUT-OUT TEST	15
[6] Procedure F: SECONDARY INTERLOCK SWITCH TEST	15
[7] Procedure F: PRIMARY INTERLOCK SYSTEM TEST	15
1. DOOR SENSING SWITCH	15
2. PRIMARY INTERLOCK RELAY (RY2)	16
[8] Procedure G: MONITOR SWITCH TEST	16
[9] Procedure H: BLOWN MONITOR FUSE TEST	16
[10] Procedure I: NOISE FILTER TEST	17
[11] Procedure J: TOUCH CONTROL PANEL ASSEMBLY TEST	17
1. Key Unit	17
2. Control Unit.	18
[12] Procedure K: KEY UNIT TEST	18
[13] Procedure L: RELAY TEST	19
[14] Procedure M: DEFROST TEST	19
[15] Procedure N: FOIL PATTERN ON THE PRINTED WIRING BOARD TEST	19
TOUCH CONTROL PANEL ASSEMBLY	21
[1] OUTLINE OF TOUCH CONTROL PANEL	21
1. Key Unit	21
2. Control Unit	21
[2] DESCRIPTION OF LSI	21
[3] SERVICING FOR TOUCH CONTROL PANEL	23
1. Precautions for Handling Electronic Components	23
2. Servicing of Touch Control Panel	23
3. Servicing Tools	23
4. Other Precautions	23
PRECAUTIONS FOR USING LEAD-FREE SOLDER	24
[1] Employing lead-free solder	24
[2] Using lead-free wire solder	24
[3] Soldering	24
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE	25
[1] WARNINGS	25
[2] OUTER CASE REMOVAL	26
[3] POWER TRANSFORMER REMOVAL	26
1. REMOVAL	26
2. REINSTALLATION	26
[4] HIGH VOLTAGE COMPONENTS REMOVAL(HIGH VOLTAGE CAPACITOR AND HIGH VOLTAGE RECTIFIER ASSEMBLY)	26
[5] MAGNETRON REMOVAL	26
1. REMOVAL	26
2. REINSTALLATION	27
[6] POSITIVE LOCK CONNECTOR (NO-CASE TYPE) REMOVAL	27
[7] CONTROL PANEL ASSEMBLY REMOVAL	27
[8] GRAPHIC SHEET AND MEMBRANE SWITCH REPLACEMENT	27
1. REMOVAL	27
2. REINSTALL	27
[9] TURNTABLE MOTOR REMOVAL	28
[10] COOLING FAN MOTOR REMOVAL	28
1. REMOVAL	28
2. INSTALLATION	28
[11] POWER SUPPLY CORD REPLACEMENT	29
1. REMOVAL	29
2. INSTALL	29
[12] DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL	29
1. REMOVAL	29
2. REINSTALL	29
[13] DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT	29
1. Adjustment	29
2. After adjustment, check the following.	30
[14] DOOR REPLACEMENT	30
1. REMOVAL	30
2. REINSTALL	30
3. After any service, make sure of the following:	30
4. SEALER FILM	31
CIRCUIT DIAGRAMS	32
[1] Pictorial Diagram (Figure S-1)	32
[2] Control Panel Circuit (Figure S-2)	33
[3] Printed Wiring Board (Figure S-3)	34
OVEN PARTS	36

Sharp R-307KW Service Manual - Page 17

] Procedure I: NOISE FILTER TEST, 11] Procedure J: TOUCH CONTROL PANEL ASSEMBLY TEST

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