Sharp R-8R51 - Page 9

R-8R51(W)
R-8R51(B)
FUNCTION
OF
IMPORTANT
COMPONENTS
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
lever.
The
3rd
latch
lever
pushes
lower
latch
head
on
the
door
upward.
The
1st
latch
head
is
linked
with
the
3rd
latch
lead,
so
now,
the
door
can
be
opened.
LATCH HOOK
ane
3RD LATCH SWITCH
UPPER LATCH LEVER
2ND LATCH SWITCH
MONITOR SWITCH
1ST LATCH SWITCH
STOP SWITCH
LOWER LATCH LEVER
OPEN BUTTON
Figure
D-1.
Door
Open
Mechanism
2ND
LATCH
SWITCH
SW2
AND
3RD
LATCH
SWITCH SW3
4.
When
the
oven
door
is
closed,
the
contacts
COM-NO
must
be
closed.
“™
9
When
the
oven
door
is
opened,
the
contacts
COM-NO
must
be
opened.
1ST
LATCH
SWITCH
SW1
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.
STOP
SWITCHE
SW5
1.
This
switch
must
make
a
contact
when
the
door
is
closed,
and
open
it
when
the
door
is
opened.
MONITOR
SWITCH
SW4
The
monitor
switch
is
activated
(the
contacts
opened)
by
the
iower
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(F6.3A)
£1
when
the
contacts
of
the
1st
latch
switch
SW1
fail
to
open
when
the
door
is
opened.
Function
4.
When
the
door
is
opened,
the
monitor
switch
SW3
contacts
close
(to
the
ON
condition)
due
to
-their
being
normally
closed.
At
this
time
the
1st
latch
switch
SW1
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
are
first
opened
and
3rd
latch
switch
contacts
are
closed
and
then
the
ist
latch
switch,
tatch
switch
and
stop
switch
contacts
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
F1
(F6.3A)
biows
simultaneously
with
closing
of
the
monitor
switch
contacts.
CAUTION:
BEFORE
REPLACING
A
BLOWN
FUSE
F.
F6.3A
TEST
THE
1ST
LATCH
SWITCH,
MONITOR
SWITCH
AND
MONITOR
RESISTOR
FOR
PROPER
OP-
ERATION.
(REFER
TO
CHAPTER
Sere
PROCEDURE").
MONITOR
RESISTOR
The
monitor
resistor
prevents
the
fuse
F1
F6.3A
burst-
ing
when
the
fuse
Fi
F6.3A
250V
blows
due
to
the
operation
of
the
monitor
switch.
NOISE
FILTER
The
noise
filter
assembly
prevents
radio
frequency
In-
terference
that
might
flow
back
in
the
power
circuit.
WEAK
POINT
WP
A017
lf
the
wire
harness
or
electrical
components
are
shortcircuited,
this
weak
point
WP
A017
blows
to
prevent
an
electric
shock
or
fire
hazzard.
ASYMMETRIC
RECTIFIER
The
asymmetric
rectifier
is
solid
state
device
that
pre-
vents
current
flow
is
both
directions.
And
it
prevents
the
temperature
rise
of
the
power
transformer
by
blowing
the
fuse
F2
F8A
when
the
high
voltage
rectifier
is
shorted.
RECTIFIER
HIGH
VOLTAGE
RECTIFIER
The
rated
peak
reverse
voltage
of
D1
of
the
asymmetric
rectifier
is
6
KV
The
rated
peak
reverse
voltage
of
D2
of
the
asymmetric
rectifier
is
1.7
KV.
D1
and
D2
of
the
asymmetric
rectifier
or
high
voltage
rectifier
are
shorted
when
the
each
peak
reverse
voltage
goes
beyond
the
each
rated
peak
reverse
voltage.
(The
process
of
the
blowing
the
fuse
F2
.
F8A.} ;
_
The
high
voltage
rectifier
is
shorted
by
any
causes
when
microwave
cooking
or
dua!
cooking.
2.
The
peak
reverse
voltage
of
D2
of
the
rectifier
goes
beyond
the
rated
peak
reverse
voltage
1.7
KV
in
the
voltage
doubler
circuit.
3.
D2
of
the
rectifier
is
shorted.
4.
The
large
electric
currents
flow
through
the
high
voltage
winding
of
the
power
transformer.
5.
The
large
electric
currents
beyond
F8A
flow
through
the
primary
widing
of
the
power
transfor-
1
mer.
6.
The
fuse
F2
F8A
blows
by
the
large
electric
cur-
rents.
7.
The
power
supplying
to
the
power
transformer
is
cut
off.