Viking RDMOS201SS, Service Manual

Page: 13 / 34

13
RDMOS201SS
DESCRIPTION AND FUNCTION OF COMPONENTS
DOOR OPEN MECHANISM
The door is opened by pushing the open button on the con-
trol panel, refer to the Figure D-1. When the open button is
pushed, the open button pushes up the switch lever, and
then the switch lever pushes up the latch head. The latch
heads are moved upward and released from latch hook.
Now the door will open.
Figure D-1. Door Open Mechanism
PRIMARY SWITCH, THIRD DOOR SWITCH & DOOR
SENSING SWITCH
The primary switch and third door switch mounted parrallel
to each other horizontally in the lower positions of the latch
hook, the door sensing switch is mounted horizontally in
the upper position of the latch hook. They are activated by
the latch head on the door. When the door is opened, the
switches interrupt the power to all high voltage components,
except the oven lamp . A cook cycle cannot take place un-
til the door is firmly closed thereby activating all interlock
switches. The secondary interlock system consists of the
door sensing switch and the secondary interlock relay located
on the control circuit board.
MONITOR SWITCH
The monitor switch is activated (the contacts opened) by the
latch head on the door while the door is closed. The switch
is intended to render the oven inoperative, by means of
blowing the C/T fuse, when the contacts of the secondary
interlock relay (RY2) and primary interlock switch fail to open
when the door is opened.
Functions:
1. When the door is opened, the monitor switch contact close
(to the ON condition) due to their being normally closed.
At this time the secondary interlock relay, primary switch
and third door switch are 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
contacts are first opened and then the door sensing
switch, primary switch and third door switch contacts
close. (On opening the door, each of these switches
operate inversely.)
3. If the door is opened, and the secondary interlock relay
(RY2) and primary interlock switch contacts fail to open,
the C/T fuse blows simultaneously with closing of the
monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN C/T FUSE
TEST THE DOOR SENSING SWITCH, SEC-
ONDARY INTERLOCK RELAY (RY2), RELAY
(RY1), PRIMARY/THIRD DOOR INTERLOCK
SWITCH AND MONITOR SWITCH FOR PROP-
ER OPERATION. (REFER TO CHAPTER "TEST
PROCEDURE").
NOTE: C/T FUSE AND MONITOR SWITCH ARE
REPLACED AS AN ASSEMBLY.
TURNTABLE MOTOR
The turntable motor rotates the turntable located on the
bottom of the oven cavity, so that the foods on the turntable
cook evenly during cooking. The turntable may turn in either
direction.
COOLING FAN MOTOR
The cooling fan motor drives a blade which draws external
cool air. This cool air is directed through the air vanes sur-
rounding the magnetron and cools the magnetron. This air
is channelled through the oven cavity to remove steam and
vapors given off from the heating foods. It is then exhausted
through the exhausting air vents at the oven cavity.
MONITOR FUSE
1. The monitor fuse blows when the contacts (COM-NO)
of the primary switch remain closed with the oven door
open and when the monitor switch closes.
2. If the wire harness or electrical components are short-
circuited, this monitor fuse blows to prevent an electric
shock or fire hazard.
CAVITY TEMPERATURE FUSE
The cavity temperature fuse located on the top of the oven
cavity, 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 cavity temperature fuse will open.
Under normal operation, the cavity temperature fuse remains
closed. However, when abnormally high temperatures are
reached within the oven cavity, the cavity temperature fuse
will open at 302
o
F(150
o
C) causing the oven to shut down.
NOTE: This is fuse. It does not reset.
C/T TEMPERATURE FUSE
The C/T fuse located near the magnetron is designed to
prevent damage to the magnetron if an over heated condition
develops in the tube due to cooling fan failure, obstructed
air guide, dirty or blocked air intake, etc.
Under normal operation, the C/T fuse remains closed.
However, when abnormally high temperatures are reached
within the magnetron, the C/T fuse will open at 302
O
F(150
O
C)
causing the oven to shut down.
1. The C/T fuse blows when the contacts (COM-NO) of the
secondary interlock relay (RY2) and primary interlock
switch remain closed with the oven door open and when
the monitor switch closes.
2. If the wire harness or electrical components are short-
circuited, this monitor fuse blows to prevent an electric
shock or fire hazard.
NOTE: This is fuse. It does not reset
Door Sensing
Switch
Monitor Switch
Switch Lever
Third Door
Switch
Latch Heads
Door
Primary
Switch