Service manual

8
R-204(W)
FUNCTION OF IMPORTANT COMPONENTS
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 temperature fuse remains
closed. However, when abnormally high temperatures are
reached within the oven cavity, the temperature fuse will
open at 248˚F(120˚C), causing the oven to shut down.
TURNTABLE MOTOR (TTM)
The turntable motor drives the turntable roller assembly to
rotate the turntable.
FAN MOTOR (FM)
The fan motor drives a blade which draws external cool air.
This cool air is directed through the air vents surrounding
the magnetron and cools the magnetron. This air is chan-
nelled through the oven cavity to remove steam and
vapours given off from heating food. It is then exhausted
through the exhausting air vents at the rear of the oven
cavity.
NOISE FILTER
The noise filter assembly prevents radio frequency inter-
ference that might flow back in the power circuit.
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 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
IST. INTERLOCK SWITCH (SW1) AND 2ND. IN-
TERLOCK RELAY CONTROL SWITCH (SW3)
1. When the oven door is closed, the contacts (COM-NO)
must be closed.
MONITOR SWITCH (SW2)
1. When the oven door is closed, the contacts (COM-NC)
must be opened.
2. When the oven door is opened, the contacts (COM-
NC) must be closed.
3. If the oven door is opened and he contacts (COM-NO)
of the ist. interlock switch (SW1) fail to open, the fuse
F8A blows immediately after closing the contacts (COM-
NC) of the monitor switch (SW2).
CAUTION: BEFORE REPLACING A BLOWN FUSE F1
TEST IST. INTERLOCK SWITCH (SW1) AND
MONITOR SWITCH (SW2) FOR PROPER
OPERATION. (REFER TO CHAPTER “TEST
PROCEDURE”).
FUSE (F1)
1. The fuse F1 blows when the contacts (COM-NO) of the
1st. interlock switch (SW1) remain closed with the oven
door open and when the contacts (COM-NC) of the
monitor switch (SW2) are closes.
2. If the wire harness or electrical components are short-
circuited, the fuse F8A blows to prevent an electric
shock or fire hazard.
HIGH VOLTAGE FUSE (F2)
The high voltage fuse blows when the high voltage rectifier
or the magnetron is shorted.
TEMPERATURE FUSE (TF)
The temperature fuse, located on the top of the oven
cavity, is designed to prevent damage to the oven by fire.
Latch Heads
Latch Hook
Door
SW3:
2nd. Interlock Relay
Control Switch
SW2:
Monitor Switch
Switch Lever
SW1:
1st. Interlock
Switch