Goldstar MA1720B Service Manual
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Goldstar MA1720B Service Manual

Goldstar MA1720B Service Manual

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MICROWAVE OVEN

SERVICE MANUAL
MODEL : MA1720W/MA1720B
CAUTION
BEFORE SERVICING THE UNIT, READ THE
SAFETY PRECAUTIONS IN THIS MANUAL.
http://www.LGEservice.com
E-mail:Techsupport@LGEservice.com

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Summary of Contents for Goldstar MA1720B

  • Page 1: Microwave Oven

    E-mail:Techsupport@LGEservice.com MICROWAVE OVEN SERVICE MANUAL MODEL : MA1720W/MA1720B CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

  • Page 2: Safety Precautions

    SAFETY PRECAUTIONS This device is to be serviced only by properly qualified service personnel. Consult the service manual for proper service procedures to assure continued safety operation and for precautions to be taken to avoid possible exposure to excessive microwave energy. PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY...

  • Page 3: Table Of Contents

    CONTENTS (Page) SAFETY PRECAUTIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Inside front cover SPECIFICATIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1-1 CAUTIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2-1 INSTALLATIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3-1...

  • Page 4: Specifications

    SPECIFICATIONS ITEM DESCRIPTION MA1720W/B MODEL 120 Volts AC 60 Hz Power Requirement 1,600 Watts Single phase, 3 wire grounded 1,200 Watts full microwave power (IEC60705) Power Output 2,450 MHz Microwave Frequency 2M282J Magnetron 0 ~ 99 min. 99 sec. Timer 19 /32 17 /32 5 /16...

  • Page 5: Cautions

    CAUTIONS Unlike other appliances, the microwave oven is MICROWAVE RADIATION high-voltage and high-current equipment. Personnel should not be exposed to the Though it is free from danger in ordinary use, microwave energy which may radiate from the extreme care should be taken during repair. magnetron or other microwave generating device if it is improperly used or connection.

  • Page 6: Installations

    INSTALLATIONS BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY. INSTALLING GROUNDING INSTRUCTIONS 1. Empty the microwave oven and clean inside it with For personal safety, this appliance must be fully a soft, damp cloth. Check for damage such as grounded at all times.

  • Page 7: Operating Instructions

    OPERATING INSTRUCTIONS FEATURES Oven Front Plate Window Door Screen Door Seal Display Window Control Panel Safety Door Lock System Turntable Rotating Ring CONTROL PANEL 1. DISPLAY WINDOW. 2. MORE / LESS: All of the one touch cook and TIMED COOK can be adjusted to cook food for a longer or shorter time.

  • Page 8: Operating Sequence

    OPERATING SEQUENCE 7. AUTO DEFROST COOKING The following is a description of component functions during oven operation. AUTO NUMBER OF STOP/CLEAR START DEFROST WEIGHT 1. SETTING THE CLOCK 8. CHILD LOCK STOP/CLEAR CLOCK NUMBER CLOCK This oven has a CHILD LOCK feature TO SET CHILD LOCK ex.) To set 4:30, touch number key [4],[3], and [0].

  • Page 9: Schematic Diagram

    SCHEMATIC DIAGRAM...

  • Page 10: Circuit Description

    CIRCUIT DESCRIPTION GENERAL DETAILS • A high voltage of approximately 2100 volts AC is generated in the secondary of the high voltage • The low voltage transformer supplies the necessary transformer which is increased by the action of the high voltage to the micom controller when power cord is voltage diode and charging of the high voltage plugged in.

  • Page 11: Service Information

    SERVICE INFORMATION TOOLS AND MEASURING INSTRUMENTS NECESSARY TOOLS NECESSARY MEASURING INSTRUMENTS Tools normally used for TV servicing are sufficient. • TESTER (VOLTS-DC, AC, Ohmmeter) Standard tools are listed below. • Microwave survey meter • Diagonal pliers - Holaday HI-1500 • Long nose pliers HI-1501 •...

  • Page 12: Record Keeping And Notification After Measurement

    MEASUREMENT WITH OUTER CASE NOTES WHEN MEASURING REMOVED • Do not exceed meter full scale deflection. • The test probe must be removed no faster than • When you replace the magnetron, measure for 1 inch/sec (2.5 cm/sec) along the shaded area, microwave energy leakage before the outer case is otherwise a false reading may result.

  • Page 13: Measurement Of Microwave Power Output

    MEASUREMENT OF MICROWAVE POWER OUTPUT • Microwave power output measurement is made with • The microwave power output P in watts is calculated the microwave oven supplied at its rated voltage and from the following formula : operated at its maximum microwave power setting with 4187 x (∆T) a load of (1000±5) g of potable water.
  • Page 14 D. PCB ASSEMBLY REMOVAL Remove choke cover 1) Remove the control panel assembly from the cavity. (Refer to control panel assembly removal on previous page.) 2) Remove screws which hold the PCB SUB ASSEMBLY to the control panel. 3) Disconnect the flat cable from the PCB SUB ASSEMBLY and take off the PCB SUB ASSEMBLY.
  • Page 15 F. MAGNETRON REMOVAL G. REMOVING THE TURNTABLE MOTOR 1) Remove the turntable and rotating ring. 1) Disconnect the leadwire from the magnetron. 2) Lay the unit down on its back. 2) Carefully remove the mounting screws holding the 3) Remove the turntable motor cover. magnetron and the waveguide.

  • Page 16: Diode Removal

    H. HIGH VOLTAGE TRANSFORMER K. INTERLOCK SYSTEM REMOVAL 1) INTERLOCK MECHANISM The door lock mechanism is a device which has 1) Discharge the high voltage capacitor. been specially designed to eliminate completely 2) Disconnect the leadwire from magnetron, high voltage microwave activity when the door is opened during transformer, and capacitor.

  • Page 17: Interlock Continuity Test

    INTERLOCK CONTINUITY TEST WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS. ALL THESE SWITCHES MUST BE REPLACED AT THE SAME TIME. TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF OR V-5230Q FOR PRIMARY SWITCH TYPE NO. SZM-V 16-FA-62, VP-532A-OF OR V-5220Q FOR MONITOR SWITCH TYPE NO.

  • Page 18: Component Test Procedure

    COMPONENT TEST PROCEDURE CAUTIONS 1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE OUTER CASE FROM THE UNIT. PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER.
  • Page 19 COMPONENTS TEST PROCEDURE RESULTS Antenna Gasket Chassis Filament NOTE: When testing the magnetron, be sure to install the magnetron gasket in the correct position and be sure that the gasket is in good condition. HIGH VOLTAGE Measure the resistance. Normal: Momentarily indicates CAPACITOR (Ohm-meter scale: Rx1000) several ohms, and...
  • Page 20 COMPONENTS TEST PROCEDURE RESULTS Check for continuity of relay 2 with an RELAY 2 POWER ohm-meter. LEVEL (Remove wire leads from relay 2 and operate the unit.) 4 sec 18 sec 6 sec 16 sec 8 sec 14 sec 10 sec 12 sec 12 sec 10 sec...

  • Page 21: Trouble Shooting

    TROUBLE SHOOTING WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER, EVALUATE THE COMPLAINT CAREFULLY. IF THE FOLLOWING SYMPTOMS APPLY, PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL. CAUTIONS 1. Check grounding before checking for trouble. 2.
  • Page 22 (TROUBLE 1) The following visual conditions indicate a probable defective control circuit. 1. Incomplete segments. • Segment missing. • Partial segment missing. • Digit flickering (NOTE: Slight flickering is normal.) 2. Colon does not turn on or blink. 3. A distinct change in the brightness of one or more numbers in display. 4.
  • Page 23 (TROUBLE 2) Oven does not operate at all, Display window does not display any figures, and no input is accepted. CONDITION CHECK RESULT CAUSE REMEDY Malfunction of the Replace fuse, Check continuity 1. Fuse blows. Continuity. primary, monitor, monitor switch. of monitor secondary switch (with...
  • Page 24 (TROUBLE 3) Display shows all figures set, but oven does not start cooking while desired program times are set and START pad is touched. CONDITION CHECK RESULT CAUSE REMEDY Defective Replace Check continuity 1. Setting time No continuity. secondary switch. secondary switch.
  • Page 25 (TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run. (Display operates properly) CONDITION CHECK RESULT CAUSE REMEDY No microwave Defective PCB Replace PCB Disconnect the No continuity. oscillation. assembly. assembly. wire leads from relay 2 and check continuity Continuity.

  • Page 26: Exploded View

    EXPLODED VIEW INTRODUCTION OVEN CAVITY PARTS INTERIOR PARTS BASE PLATE PARTS DOOR PARTS LATCH BOARD PARTS CONTROL PANEL PARTS...

  • Page 27: Door Parts

    DOOR PARTS 13552A 13536A 13213A 13352A 13720D 14026A 14970A 13581A...

  • Page 28: Controller Parts

    CONTROLLER PARTS 24781M 268711 23550D 23572A WTP018 23506A...

  • Page 29: Oven Cavity Parts

    OVEN CAVITY PARTS 948502 WSZ185 33112U 33052A WTT010 WTT020 33390G 36549S 35889A WTP013...

  • Page 30: Latch Board Parts

    LATCH BOARD PARTS 948501 WSZ085 43501A 43500A 466001 56912B 466003 466001...

  • Page 31: Interior Parts

    INTERIOR PARTS WSZ002 55006F 568771 56411A 50FZZA 56930V 34930W 56549F WSZ085 54974S WSZ187 55900A WTT037 WSZ002 WTT028 50CZZH 35012A 54810C 56324A WTT028 WSZ002 WSZ002 56851D...
  • Page 32 BASE PLATE PARTS 56170D 63302A 63303A 65006B WSZ002 WTT021...

  • Page 33: Schematic Diagram Of P.c.b

    SCHEMATIC DIAGRAM OF P.C.B.

  • Page 34: Printed Circuit Board

    PRINTED CIRCUIT BOARD...
  • Page 35 Apr, 2002 P/NO : 3828W5S2188 Printed in Korea...

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Ma1720w

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