Panasonic NN-8508 - Page 22

NN-8508, NN-8558
NN-8808, NN-8858
NN-8808P
6.
Humidity
sensor
and
digital
programmer
circuit
(See
Fig.
37)
SENSOR
HEATER
TERMINALS
CAUTION
Do not touch any parts of the circuitry on the digital
programmer
circuit
since
static
electric
discharge
may damage this control panel.
Always ground yourself while working on this panel to
discharge
any
static
charge
built
up
in
your
body.
J U
I tj
att
Spinanil
(A)
Check
across
sensor
heater
terminals
with
7-pin
connector
(CNS)
un-
plugged.
Normal
cold
resistance
should
read
approx.
4.5
ohm.
(B)
In
order
to
determine
if
the
Auto
Sensor
Cooking
function
of
the
digital
HUMIDITY
SENSOR
programmer
circuit
is
in
working
order
or
not,
do
the
following
test.
1)
Place
a
w=7er
load
in
the
oven.
2)
Unsolder
.
Brown/White
wires
connected
to
sensor
terminals.
Fig.
37
3)
Tap
Auto
Sensor
Cook
Control
Pad
six
times
to
set
Auto
Sensor
Cooking
6
and
tap
Start
Pad
4)
About
10
seconds
after Start
Pad
is
tapped,
short
Brown/White
wires
for
5
seconds
and
then
remove
them.
Before
shorting
the
Brown/White
wires
you
can
watch
the
sensor
heater
glow
red.
5)
Approx.
75
seconds
after
the
Start
Pad
is
tapped,
short
the
Brown/
White
wires
again.
6)
6
should
disappear
in
display
window
and
following
digits
(see
chart)
should
appear
indicating
**balance
of
cooking
time
(T2
TIME).
The
time
should
start
to
count
down
and
oven
should
shut
off
when
the
time
has
elapsed.
“T2 TIME
(balance of cooking time)
70 sec.~79 sec. 4 sec.
80 sec.~89 sec. 5 sec.
The
Auto
Sensor
Cooking
function
in
the
digital
programmer
circuit
is
in
working
order
if above
condition
is
obtained.
7. To test the oven temp sensor thermistor
This
sensor
monitors
the
heat
produced
by
the
heater
circuit
and
maintains
the
oven
temperature
the
user
had
selected.
Normal
room
temperature,
especially
in
a
kitchen
can
vary
anywhere
from
50°F
to
90°F.
The
reading
across
the
oven
sensor
thermistor
should
be
within
360K
ohm
to
800K
ohm
when
reading
in
an
area
within
the
50°F
to
90°F
room
temperature
range.
If
the
resistance
reading
is
out
of
the
range
stated
here,
the
sensor
is
defective
and
must
be
replaced.
NOTE
1:
When
measuring
resistance
disconnect
the
4-pin
connector
(CN3)
from
the
DPC
otherwise
a
false
reading
may
be
indi-
cated.
NOTE
2:
If
checking
an
oven
sensor
thermistor
just
after
the
microwave
oven
has
been
operating,
the
sensor
of
course
won't
be
room
temperature.
In this
case
the
sensor
must
be
removed
and
allowed
to
cool
down
to
the
50°F
to
90°F
range.
SENSOR
TERMINALS