R-25JT-F
9
DOOR OPEN MECHANISM
1. The door release lever is pulled.
2. The upper latch head is lifted up by the linked door release
lever.
3. The latch lever is lifted up by the door release lever.
4. The joint lever is lifted up by the latch 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.
Figure D-1. Door Open Mechanism
DOOR SENSING SWITCH
The door sensing switch is activated by the latch head of the
door and switch lever C. When the door is opened, the contacts
of the switch open and interrupt the circuit to the coils of the
primary interlock relays (1), (2). The contacts of the primary
relays (1), (2) then open and interrupt the circuit to the primary
winding of the power transformers. At this time, the contacts of
relay RY1 close and the blower motor, stirrer motors and oven
lamps are energized for 1 minute.
SECONDARY INTERLOCK SWITCHES (1), (2)
The secondary interlock switches (1), (2) are activated by the
upper latch head of the door and switch lever B. When the door
is opened, the contacts of the switch open and interrupt the
circuit to the primary winding of the power transformers (1), (2).
MONITOR SWITCHES (1), (2)
The monitor switches (1), (2) are mounted in the upper position
of the latch hook. The monitor switches are activated by the
upper latch head of the door and switch lever A. When the door
is opened, the contacts of the monitor switches close. Monitor
switch (1) is intended to render the oven inoperative by means
of blowing the monitor fuse, when the contacts of the primary
interlock relay (1) and secondary interlock switch (1) fail to open
when the door is opened. Monitor switch (2) is intended to
render the oven inoperative by means of blowing the monitor
fuse, when the contacts of the primary interlock relay (2) and
secondary interlock switch (2) fail to open when the door is
opened.
DESCRIPTION AND FUNCTION OF COMPONENTS
Functions:
With the door shut, the contacts of the door sensing switch and
the secondary interlock switches (1), (2) are closed and the
contacts of the monitor switches (1), (2) are open.
1. When the door is opened, the contact of the door sensing
switch and secondary interlock switches (1), (2) are opened
first, then the contact of the monitor switches (1), (2) are
closed.
2. As the door goes to a closed position, the contacts of the
monitor switches (1), (2) are opened first, then the contacts
of the door sensing switch and the secondary interlock
switches (1), (2) close.
3. If the door is opened, and the contacts of the primary
interlock relay and secondary interlock switch of the same
circuit fail to open, the monitor fuse blows simultaneously
with closing of the monitor switch contacts of that circuit (1
or 2).
CAUTION: BEFORE REPLACING A BLOWN MONITOR
FUSE TEST THE DOOR SENSING SWITCH,
PRIMARY INTERLOCK RELAYS (1), (2), SEC-
ONDARY INTERLOCK SWITCHES (1), (2) AND
MONITOR SWITCHES (1), (2) FOR PROPER
OPERATION. (REFER TO CHAPTER "TEST
PROCEDURE").
NOTE: MONITOR FUSE AND SWITCH ARE REPLACED
AS AN ASSEMBLY.
MAGNETRON TEMPERATURE FUSES (1), (2)
The temperature fuses (1), (2) located on the top of the upper
and lower waveguide, are designed to prevent damage to the
magnetrons (1), (2). 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. However, when abnormally high temperatures
are generated within the magnetron, the temperature fuse will
open at 302˚F (150˚C) causing the microwave energy to stop.
The defective temperature fuse must be replaced with new
rated one.
OVEN TEMPERATURE FUSE
The temperature fuse, 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 temperature fuse will open. Under
normal operation, the oven temperature fuse remains closed.
However, when abnormally high temperatures are generated
within the oven cavity, the oven temperature fuse will open at
248˚F (120˚C), causing the oven to shut down. The defective
temperature fuse must be replaced with new rated one.
OVEN THERMISTOR (1)
The thermistor is a negative temperature coefficient type. The
temperature in the exhaust duct is detected through the resist-
ance of the thermistor.
If the temperature is high, the control panel will display “EE7”
and the oven will stop to avoid overheating and catching fire.
If the thermistor is open, the control panel will display "EE6" and
the oven will stop.
Latch head
Monitor switch (1)
Latch hook
Secondary interlock
switch (2)
Door sensing switch
Latch head
Joint lever
Door release
lever
Latch lever
Secondary interlock
switch (1)
Monitor switch (2)
Switch lever C
Switch lever A
Switch lever B
