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When the door button is slowly depressed with the
door closed, an audible "click" should be heard at
the same time or successively at intervals. When
the button is slowly released, the latches should
activate the switches with an audible "click". 
If the latches do not activate the switches when the
door is closed, the switches should be a adjusted  in
accordance with adjustment procedure. Disconnect
the wire lead from the primary switch. Connect the
multimeter leads to the common (COM) and
normally open (NO) terminal of the switch. The
meter should indicate an open circuit in the door
open 
condition.
When the door is closed, the meter should indicate
a closed circuit.
When the primary switch operation is abnormal,
make the necessary adjustment or replace the
switch only with the same type of switch.

Disconnect the wire lead from the secondary switch.
Connect the multimeter leads to the common (COM)
and normally open (NO) terminals of the switch. The
meter should indicate a open condition. When the
door is closed, meter should indicate an closed
circuit. When the secondary switch operation is
abnormal, make the necessary adjustment or
replace the switch only with the same type of switch.

Disconnect the wire lead from the monitor switch.
Connect the multimeter leads to the common (COM)
and normally close (NC) terminals of the switch. The
meter should indicate closed circuit in the door open
condition. When the door is closed, meter should
indicate an closed circuit.When the monitor switch
operation is abnormal, replace the same type of
switch.

17

SWITCHES

Check for continuity of the switch

(Wire leads removed)

with a Multi-meter

Primary
Switch

Monitor
Switch

Secondary
Switch

NOTE: After checking for the continuity of switches, make sure that are

correctly connected.

Door
open

Door
close

COM

NO

COM

NC

COM  

NO

COM  

NO

TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF FOR PRIMARY / SECONDARY SWITCH
TYPE NO. SZM-V 16-FA-61 OR VP-531A-OF FOR MONITOR SWITCH

18

1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE OUT

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. (SEE PAGE 5)

2. ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER OF

WATER IN CONTAINER) IN THE OVEN.

HIGH VOLTAGE
TRANSFORMER
(Wire leads removed)

1. Measure the resistance.

(Multi-meter scale: R 

✕

1)

●

Primary winding 

Approx: 1.4 

Ω

●

Secondary winding 

Approx: 90 

Ω

●

Filament winding 

Less than: 0.1 

Ω

2. Measure the resistance.

(Multi-meter scale: R 

✕

1000)

●

Primary winding to ground 

Normal: 

∞

.

●

Filament winding to ground 

Normal: 

∞

.

MAGNETRON 

1. Measure the resistance.

(Wire leads removed)

(Multi-meter scale: R 

✕

1)

●

Between filament terminals

Normal: Less than 1 

Ω

2. Measure the resistance.

(Multi-meter scale: R 

✕

1000)

●

Filament to chassis.

Normal: 

∞

.

Secondary

Winding

Filament

Winding

Terminal

Filament

Winding

Terminal

Primary

Winding

19

HIGH VOLTAGE
CAPACITOR

Antenna

Gasket

Filament
Terminals

Chassis

Normal : Momentary indicates

several ohms, and
then gradually
returns to infinite.

Normal : 

∞

.

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. 

Measure the resistance.
(Multi-meter scale : Rx1000) 

●

Terminal to termonal.

Measure the resistance.
(Multi-meter scale : Rx1000) 

●

Terminal to case.

Measure the continuity (Forward).
(Multi-meter scale : Rx10000) 

Measure the continuity (Reverse).
(Multi-meter scale : Rx10000) 

Normal : 

∞

.

Abnormal : Continuity.

Normal : Continuity.
Abnormal : 

∞

.

HIGH VOLTAGE
DIODE

NOTE :
Some inexpensive
meter may indicate
infinite resistance in
both direction.

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.

A) Do not operate or allow the oven to be operated with the door open.

B) Make the following safety checks on all ovens to be serviced before activating the magnetron or other

microwave source, and make repairs as necessary; (1) interlock operation, (2) proper door closing,  (3)

seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and

latches, (5) evidence of dropping or abuse.

C) Before turning on microwave power for any service test or inspection within the microwave generating

compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment,

integrity, and connections.

D) Any defective or misadjusted 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 should be performed on each oven prior to release to the owner.

DO NOT BECOME EXPOSED TO RADIATION FROM THE MICROWAVE GENERATOR
OR OTHER PARTS CONDUCTING MICROWAVE ENERGY.