R-24AT (serv.man2). Complete - Sharp Home Appliance Service Manual (repair manual). Page 8

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1. The door release lever is pulled.
2. The upper latch head is lifted up by the linked door

release lever.

3. The head lever is lifted up by the door release lever.
4. The joint lever is lifted up by the head lever.
5. The lower latch head is lifted up by the joint lever.
6. Now both latch heads are lifted up, so they can be

released from the latch hook.

7. Now the door can be opened.

1. When the oven door is closed, the contacts COM-NO

must be closed.

2. When the oven door is opened, the contacts COM-NO

must be opened.

The monitor switch SW4 is activated (the contacts opened)
the upper latch head and switch lever A while the door is
closed. The switch is intended to render the oven inopera-
tive by means of blowing the fuse F2 F6.3A when the
contacts of the 1st latch switch SW1 fail to open when the
door is opened.

Function
1. When the door is opened, the monitor switch SW4

contacts close (to the ON condition) due to their being
normally closed. At this time the 1st latch switch SW1
is in the OFF condition (contacts open) due to their
being normally open contact switches.

2. As the door goes to a closed position, the monitor

switch SW4 contacts are opened and 1st latch switch
SW1 contacts are closed (On opening the door, each
of these switches operate inversely.)

3. If the door is opened and the 1st latch switch SW1

contacts fail to open, the fuse F2 F6.3A blows simulta-
neously with closing of the monitor switch SW4 con-
tacts.

CAUTION:BEFORE REPLACING A BLOWN FUSE F2

F6.3A TEST THE 1ST LATCH SWITCH SW1,
MONITOR SWITCH SW4 AND MONITOR
RESISTOR R1 FOR PROPER OPERATION.
(REFER TO CHAPTER “TEST PROCE-
DURE”).

The monitor resistor R1 prevents the fuse F2  F6.3A 250V
bursting when the fuse F 2 F6.3A 250V blows due to the
operation of the monitor switch SW4.

The noise filter assembly prevents radio frequency inter-
ference that might flow back in the power circuit.

If the wire harness or electrical components make a short-
circuit, this fuse F1 (F13A) blows to prevent an electric
shock or fire hazard.

1. If the wire harness or electrical components are short-

circuited, this fuse blows to prevent an electric shock or
fire hazard.

2. The fuse F2 also blows when 1st latch switch SW1

remains closed with the oven door open and when the
monitor switch closes.

If the wire harness or the high voltage transformers T1, T2
are short-circuited, these fuses F3 and /or F4 blow to
prevent an electric shock or fire hazard.

The high voltage fuse blows when the high voltage rectifier
or the magnetron is shorted.

The temperature fuses TF1, TF2 located on the top of the
upper and lower waveguide, are designed to prevent
damage to the magnetrons MG1, MG2. If an over heated
condition develops in the tube due to blower motor failure,
obstructed air ducts, dirty or blocked air intake, etc., the
circuit to the magnetrons are interrupted. Under normal
operation, the temperature fuses remains closed. How-
ever, when abnormally high temperatures are generated
within the magnetrons, the temperature fuses will open at
150˚C causing the microwave energy to stop. The defec-
tive temperature fuses must be replaced with new rated
ones.

The temperature fuse TF4, located on the side of the
exhaust duct assembly, is designed to prevent damage to
the oven by fire. If the food load is overcooked, by either
error in cook time or defect in the control unit, the tempera-
ture fuse will open. Under normal operation, the oven
temperature fuse remains closed. However, when abnor-
mally high temperatures are generated within the oven

Latch head

SW4: Monitor switch

Latch hook

SW1: 1st. latch switch

SW2: 2nd. latch switch

SW5: Stop switch

SW3: 3rd. latch switch

Latch head

Joint lever

Door release
lever

Head lever