Read Sharp R-556D (serv.man2) Service Manual online
R556D
6 – 1
R556D
Service Manual
CHAPTER 6.
FUNCTION OF IMPOR-
TANT 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.
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.
Figure D-1. Door Open Mechanism
[2] 1ST. LATCH SWITCH AND 2ND. INTER-
LOCK RELAY CONTROL SWITCH
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 2nd. interlock relay fail to open, the fuse F10A
blows simultaneously with closing the contacts (COM-NC) of the
monitor switch.
blows simultaneously with closing the contacts (COM-NC) of the
monitor switch.
CAUTION: BEFORE REPLACING A BLOWN FUSE F10A TEST THE
1ST. LATCH SWITCH, 2ND. INTERLOCK RELAY, MONI-
TOR SWITCH MONITOR RESISTOR FOR PROPEROP-
ERATION.
TOR SWITCH MONITOR RESISTOR FOR PROPEROP-
ERATION.
[4] FUSE F10A
1. The fuse F10A blows when the contacts (COM-NO) of the 1st. latch
switch and 2nd. interlock relay remain closed with the oven door
open and when the monitor switch closes.
open and when the monitor switch closes.
2. If the wire harness or electrical components are short-circuited, this
fuse F10A blows to prevent an electric shock or fire hazard.
[5] HIGH VOLTAGE FUSE
The high voltage fuse blows when the high voltage rectifier or the mag-
netron is shorted.
netron is shorted.
[6] OVEN TEMPERATURE FUSE
The 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 over-
cooked, 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
150
designed to prevent damage to the oven by fire.If the food load is over-
cooked, 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
150
°C, causing the oven to shut down.
[7] MAGNETRON TEMPERATURE FUSE
The temperature fuse located near the magnetron is designed to pre-
vent damage to the magnetron if an overheated condition develops in
the tube due to cooling fan failure, obstructed air guide, dirty or
blocked air intake, etc.Under normal operation, the temperature fuse
remains closed. However, when abnormally high temperatures are
reached within the magnetron, the temperature fuse will open at
150
vent damage to the magnetron if an overheated condition develops in
the tube due to cooling fan failure, obstructed air guide, dirty or
blocked air intake, etc.Under normal operation, the temperature fuse
remains closed. However, when abnormally high temperatures are
reached within the magnetron, the temperature fuse will open at
150
°C causing the oven to shut down.
[8] TURNTABLE MOTOR
The turntable motor drives the turntable roller assembly to rotate the
turntable.
turntable.
[9] FAN MOTOR
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 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.
air is directed through the air vents 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.
[10] NOISE FILTER
The noise filter prevents the radio frequency interference that might
flow back in the power circuit.
flow back in the power circuit.
Door
S witch Lever
Latch
Heads
Heads
Latch Hook
Monitor S witch
2nd. Interlock
R elay C ontrol
S witch
R elay C ontrol
S witch
1s t Latch S witch
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