R-7N76(W)M
R-7N76(B)M
6
FUNCTION OF IMPORTANT COMPONENTS
FUSE 13A 250V
If the wire harness or electrical components are short-
circuited, this fuse 13A 250V blows to prevent an electric
shock or fire hazard.
FUSE M8A 250V
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 also blows when 1st latch switch remains closed
with the oven door open and when the monitor switch
contact (COM-NC) closes.
3. The fuse also blows when the asymmetric rectifier, H.V.
rectifier,.H.V. wire harness, H.V. capacitor, magnetron or
secondary winding of high voltage transformer is shorted.
TC TRANSFORMER
TC transformer converts A.C. line voltage into low voltage to
drive the control unit.
THERMAL CUT-OUT 170˚C (OVEN)
The thermal cut out protects the oven against overheating
during grill cooking, convection cooking or dual (combina-
tion) cooking. If the temperature rises above 170˚C because
the fan motor is interrupted, the air inlet duct is blocked or the
ventilation openings are obstructed, the thermal cut-out
opens and switches off the all electrical parts.
The defective thermal cut-out must be replaced with a new
one.
THERMAL CUT-OUT 125˚C (MG)
This thermal cut-out protects the magnetron against over-
heat. If the temperature goes up higher than 125˚C because
the fan motor is interrupted or the ventilation openings are
blocked, the thermal cut-out will open and line voltage to the
high voltage transformer will cut off, and operation of the
magnetron will be stopped. The defective thermal cut-out
must be replaced with a new one.
THERMAL CUT-OUT 190˚C (CONV.)
The thermal cut out protects the convection motor against
overheating. If the temperature of the thermal cut-out rises
above 190˚C because the convection fan is interrupted, the
ventilation openings are obstructed or the other abnormal
matter occurs, the thermal cut-out opens and switches off
the convection heating element and conv. indicator light.
When the oven cools itself down to the operating tempera-
ture of 170˚C, the contacts of the thermal cut-out will close
again.
DOOR OPEN MECHANISM
The door can be opened by pushing the open button on the
control panel. When the open button is pushed, the open
lever pushes lower latch head on the door upward. The
upper latch head is linked with the lower latch head, so now,
the door can be opened.
Figure D-1. Door Open Mechanism
1ST LATCH SWITCH, 2ND LATCH SWITCH AND
STOP SWITCH
1. When the oven door is closed, the contacts COM-NO of
each switch must be closed.
2. When the oven door is opened, the contacts COM-NO of
each switch must be opened.
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 fuse M8A when the contacts of the 1st latch
switch fail to open when the door is opened.
Function
1. When the door is opened, the contacts (COM-NC) of
monitor switch SW4 close (to the ON condition) due to
their being normally closed.
At this time the 1st latch 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
contacts (COM-NC) are opened and 2nd latch switch
contacts COM-NO are closed and then contacts of 1st.
latch switch and stop switch close. (On opening the door,
each of these switches operate inversely.)
3. If the door is opened and the 1st latch switch contacts fail
to open, the fuse M8A) blows immediately after closing of
the monitor switch (COM-NC) contacts.
CAUTION: BEFORE REPLACING A BLOWN FUSE M8A
TEST THE 1ST LATCH, MONITOR SWITCH
AND MONITOR RESISTOR FOR PROPER
OPERATION.(REFER TO CHAPTER “TEST
PROCEDURE”).
MONITOR RESISTOR
The monitor resistor prevents the fuse M8A bursting when
the fuse M8A blows due to the operation of the monitor
switch circuit.
ASYMMETRIC RECTIFIER
The asymmetric rectifier is a solid state device that prevents
current flow in both directions. And it prevents the tempera-
ture rise of the power transformer by blowing the fuse M8A
when the high voltage rectifier is shorted.
LATCH
HEADS
LATCH HOOK
1ST LATCH
SWITCH
2ND LATCH SWITCH
STOP SWITCH
OPEN LEVER
DOOR OPEN BUTTON
MONITOR LATCH
SWITCH
D2
D1
ASYMMETRIC
RECTIFIER
HIGH VOLTAGE RECTIFIER
