Description And Function Of Components; Test Procedures - Sharp R-426LS Service Manual

2. Cooking Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. COOKING TIME PROGRAMMED.
3. VARIABLE COOKING CONTROL "P-HI".
4. START PAD TOUCHED.
H
GRN
C1
GND
120VAC
60Hz
N
C1: LINE CROSS CAPACITOR ------- 0.22uF/ AC250V
C2, C3: LINE BYPASS CAPACITOR ------ 0.033uF/ AC250V

[3] DESCRIPTION AND FUNCTION OF COMPONENTS

1. DOOR OPEN MECHANISM
The door is opened by pushing the open button on the control panel,
refer to the Figure D-1. When the open button is pushed, the open but-
ton 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.
Door
Switch Lever
Figure D-1. Door Open Mechanism.
2. DOOR SENSING AND PRIMARY INTERLOCK
SWITCHES
The primary interlock switch is mounted in the lower position of the
latch hook and the door sensing switch in the secondary interlock sys-
tem is mounted in the upper position of the latch hook. They are acti-
vated by the latch heads on the door. When the door is opened, the
switches interrupt the power to all high voltage components.
C2
C3
(RY1)
OVEN LAMP
RELAY
NOISE
FILTER
Figure O-2. Oven Schematic-Cooking Condition
Latch Heads
Door Sensing
Switch
Monitor Switch
Primary Interlock
Switch
B2
DOOR
SENSING
SWITCH
B1
(RY2) F-3
SECONDARY
INTERLOCK
RELAY
F-2
CONTROL UNIT
F-1
MONITOR
SWITCH
TURN
OVEN FAN
FM
OL
TTM TABLE
LAMP MOTOR
MOTOR
COM. N.O.
PRIMARY INTERLOCK
SWITCH
A cook cycle cannot take place until the door is firmly closed there by
activating both interlock switches. The secondary interlock system
consists of the door sensing switch and secondary interlock relay
located on the control circuit board.
3. 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 monitor 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 (RY2) and primary interlock 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 and the primary
interlock 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 monitor fuse
blows simultaneously with closing of the monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN MONITORFUSE TEST
THE DOOR SENSING SWITCH, SECONDARY INTER-
LOCK RELAY (RY2), RE-LAY (RY1), PRIMARY INTER-
LOCK SWITCH AND MONITOR SWITCH FOR PROPER
OPERATION. (REFER TO CHAPTER "TEST PROCE-
DURE").
NOTE: MONITOR FUSE AND MONITOR SWITCH ARE REPLACED
AS AN ASSEMBLY.
6 – 3
POWER TRANSFORMER
HIGH
VOLTAGE
CAPACITOR
0.94uF/ AC2200V
N.C.
HIGH
VOLTAGE
RECTIFIER
COM.
R426LS