Panasonic NN-8508 - Page 25

NN-8508, NN-8558
NN-8808, NN-8858
NN-8808P
TROUBLESHOOTING GUIDE
CAUTION
.
Check
grounding
before
checking
for
trouble.
.
Be
careful
of
the
high
voltage
circuit.
.
Discharge
high
voltage
capacitor.
(See
page
15.)
. When
checking
the
continuity
of
the
switches
or
the
high
voltage
transformer,
disconnect
one
lead
wire
from
these
parts
and
then
check
continuity
with
the
AC
plug
removed.
To
do
otherwise
may
result
in
a
false
reading
or
dam-
age
to
your
meter.
5.
Do
not
touch
any
parts
of
the
circuitry
on
the
digital
programmer
circuit,
since
static
electric
discharge
may
dam-
age
this
control
panel.
Always
touch
yourself
to
ground
while
working
on
this
panel
to
discharge
any
static
charge
in
your
body.
6.
A
120V
AC
is
present
at
the
shaded
area
of
the
digital
programmer
circuit
(Terminals
of
power
relaies
and
primary
circuit
of
low
voltage
transformer).
When
troubleshooting,
be
cautious
of
possible
electrical
shock
hazard.
hop —
First
of
alloperate
the
microwave
oven
following
the
correct
operating
procedures
described
on
pages
31
~
33
inorder
to
find
the
exact
cause
of
any
trouble.
{TROUBLE 1] Oven does not start cooking
No
Does
display
show
Yes
any
figure?
Yes
Set
power
and
cooking
is
fuse
blown?
time
and
then
tap
start
pad
Please proceed to No Is fan motor
"TROUBLE 2" . rotating?
No
Check
thermal
Abnormal
Defective
latch
switch
cutout A
Yes
Defective thermal No Is 120V applied to
cutout high voltage
transformer?
Normal
Yes
Check low voltage Abnormal No Is 18(12)V DC Defective H.V.T., Diode,
transformer
applied
to
power
or
Magnetron
relay B?
Normal
Yes
Defective
D.P.C.
See
Defective
D.P.C.
See
Defective
power
relay
“TROUBLE 4" Defective L.V.T. “TROUBLE 4" B