Chapter 6. Function Of Important Compo; Door Open Mechanism; 1St. Latch Switch And 2Nd. Inter- Lock Relay Control Switch; Monitor Switch - Sharp R-222T Service Manual

R-222T(W)
CHAPTER 6.
FUNCTION OF IMPORTANT COMPONENTS
R200K

[1] DOOR OPEN MECHANISM

The door is opened by pulling the door, refer to the Figure D-1.
Door
Latch
Heads
Switch Lever
Figure D-1. Door Open Mechanism
[2] 1ST. LATCH SWITCH AND 2ND. INTER-
LOCK RELAY CONTROL SWITCH
1. When the oven door is closed, the contacts (COM-NO) must be
closed.
2. When the oven door is opened, the contacts (COM-NO) must be
opened.

[3] MONITOR SWITCH

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 the contacts (COM-NO) of the 1st
latch switch and the 2nd. interlock relay (RY2) fail to open, the fuse
(T6.3A) blows simultaneously with closing the contacts (COM-NC)
of the monitor switch.
CAUTION: BEFORE REPLACING A FUSE (T6.3A) TEST THE 1ST.
LATCH SWITCH AND 2ND. INTERLOCK RELAY (RY2)
AND MONITOR SWITCH FOR PROPER OPERATION.
(REFER TO CHAPTER "TEST PROCEDURE".)

[4] FUSE T6.3A

1. The fuse (T6.3A) blows when the contacts (COM-NO) of the 1 st.
latch switch and the 2nd. interlock relay (RY2) remain closed with
the oven door open and when the monitor switch closes.
2. If the wire harness or electrical components are short-circuited, the
fuse (T6.3A) blows to prevent an electric shock of fire hazard.

[5] HIGH VOLTAGE FUSE

The high voltage fuse blows when the high voltage rectifier or the mag-
netron is shorted.
Latch Hook
2nd. Interlock
Relay Control
Switch
Monitor Switch
1 st. Latch
Switch
6 – 1
Service Manual

[6] TEMPERATURE FUSE 150C (OVEN)

The temperature fuse located on the top of the oven cavity is designed
to prevent damage to the oven if the foods in the oven catch fire due to
over heating produced by improper setting of cook time or failure of
control unit. 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 150°C, caus-
ing the oven to shut down. The defective temperature fuse must be
replaced with a new one.

[7] TURNTABLE MOTOR

The turntable motor drives the turntable roller assembly to rotate the
turntable.

[8] FAN MOTOR

The fan motor drives a blade which draws external cool air. This cool
air is directed through the air vanes surrounding the magnetron and
cools the magnetron. This air is channelled through the oven cavity to
remove steam and vapours given off from the heating foods. It is then
exhausted through the exhausting air vents at the oven cavity.

[9] NOISE FILTER

The noise filter prevents the radio frequency interference that might
flow back in the power circuit.