Panasonic NE-7910 User manual

NE-7910
NE-7910C
NE-7910, NE-7810 for U.S.A.
NE-7910C, NE-7810C for Canada
SPECIFICATIONS
NE-7910 NE-7910C NE-7810, NE-7810C
ice Manual
Microwave Oven
NE-7910, NE-7910C
NE-7810, NE-7810C
NE-7810
NE-7810C
Power Source
115V AC Single Phase: 60Hz
Power Requirement
1.61 KW (14 A)
High Frequency Output
7O0OW: full power
epiflatian rorioanc
Oscillation Frequency
y [lA RALIS
2450 MHz
Magnetron
2M157-M1
Timer
99 minutes 99 seconds
Cooling Method
Air Cooling
Approximate Outside Dimensions
24-3/4" (W) x 18-1/2” (D) x 14-3/4""(H)
63.0 cm (W) x 47.0 cm (D) x 37.5 cm (H)
Approximate Oven Cavity
Dimensions
15-1/2” (W) x 15-1/2" (D) x 9-1/2" (H)
39.5 cm (W) x 39.5 cm (D) x 24.0 cm (H)
Approximate Weight
70 Ibs
31.8 Kg
Specifications subject to change without notice.
Panasonic Company
a
Division of Matsushita Electric Corporation of America Panasonic Hawaii, Inc.
® One panasonic Way, Secaucus, N.J. 07094 {201} 348-7000
Matsushita Electric of Canada Ltd.
320 Waiakamilo Road, Honolutu, Hawaii 96817 40 Ronson Drive, Rexdale, Ont. M9W 1B5
Ado

WARNING
1. This product should be serviced only by trained qualified personnel.
2. Though this product has been manufactured in compliance with:
~pederal Performance Standard 21 CFR Subchapter J’? (HEW): NE-7910, NE-
‘or “Radiation ‘Emitting Devices Act” (NHW):. NE-7910C, NE-7810C _ fe
it is very important: when servicing to avoid being exposed to. exc icrowave
ee radiation ‘his ‘may be hazardous. © All repairs: should be. made i in accordance with. a
procedures described in this manual.” eae BS me
7810.
ive
3. Check for radiation leakage after every. servicing according to the * “procedure for
mea l uring radiation leakage’? on pages 23 to 25. :
4. Any ‘serviceman: who learns of any accident pertaining to micro
should immediately notify the appropriate address listed below. 2
IN U. s. A. ng ee PANASONIC COMPANY Bivision of Matsushita”
(M ECA) | Electric Corporation of America
One Panasonic Way, Secaucus, New Jersey 07094
Attention: Quality Assurance Dept. .
[phone]
IN HAWAII PANASONIC HAWAII, INC.
_
(PHI)
320
Waiakamilo
Road,
Honolulu,
96817
[phone]
IN CANADA MATSUSHITA ELECTRIC OF CANADA LIMITED
~ (MELCA) 40 Ronson Drive, Rexdale, Ontario, Canada, M9OW 1B5
[phone]
5. There are special components used in the microwave oven which are important for
safety. These parts are shaded on the schematic diagram and on the replacement parts
- list. It is essential that these critical parts should be replaced with manufacturer’s
specified parts to prevent microwave leakage, shock, fire, or other hazards. Do not
modify the original design. ,

ERISA
ION
cco
ek
I
Es
Bigs
er
ae
RRR
IES
Se
DOOR
ETE
3
OPERATION
....--0
0c
eee
e
reenter
testes
ele
ew
lele
ewe
ee
de
eed
ey
eee
ea
wee
te
ae
S|
CAUTION
WHEN
USING...
5-2.¢dcnceie
Sete
et
cen
ne
Satan
tee
mee
EN
mer
STE
tS
10
SCHEMATIC
DIAGRAM
ssc,
5
aks
cn
eretts
es
Eh
Se
einen
eee
oe
RNa
EE
11
BIRCUIT
DESCRIPTION
6
4-2
Se
een
asia
ele
Pelee
wie
sae
ae
otal
ges
por
hae
ER
12
PRECAUTIONS
TO
BE
OBSERVED
BEFORE
AND
DURING
SERVICING
Gogh
SG
TO
AVOID
POSSIBLE
EXPOSURE
TO
EXCESSIVE
MICROWAVE
ENERGY
...----
ese
seer
eee
15
CAUTIONS
TO
BE
OBSERVED
WHEN
TROUBLESHOOTING
......-20
eee
eee
e
eee
e
eres
e
1B
DISASSEMBLY
AND
PARTS
REPLACEMENT
PROCEDURE.....-.--0
cece
creer
tenets
16.
MEASUREMENT
AND
ADJUSTMENT.
......---00
ee er
errr
teers
eres
stresses
esses
20
(Including
the
Safety
Interlock
Switch
Circuit)
;
,
PROCEDURE
FOR
MEASURING
RADIATION
LEAKAGE
.....cc
ccc
e
eee
cree
eee
e
en
neeee
23
CUSTOMER
COMPLAINTS
NOT
RELATED
TO
OVEN
FAILURE
1.0.0...
eee
eee
eee
tees
26
TROUBLESHOOTING
GUIDE...
260i
cece
eee
ee
eee
e
cnet
e
teens
t
erent
ere
see
ees
27
COMPONENT
TEST
PROCEDURE
.......
0...
eee
eee
reser
eres
crs
r
erste
reser
32
DIGITAL
PROGRAMMER
CIRCUIT
TEST
PROCEDURE
©
Ac
hara
Satara
Poaceae
ssneh
Deut
ae
EON
NECESSARY
TOOLS
AND
MEASURING
INSTRUMENTS
.....---2
eee
ere
reer
ernest
35
EXPLODED
VIEW
AND
PARTS
LIST
.....
0...
0
secre
ee
errr
errr
reterr
ents
sete
senses
eee
36
INSTALLATION
.
Check
the
grounding.
.
Confirm
the
power
source
capacity.
Use
the
microwave
oven
in
an
ambient
temperature
of
less
than
104°F
(40°C).
.
Avoid
using
the
microwave
oven
where
humidity
is
high.
.
Position
the
microwave
oven
away
from
radios,
TV's,
etc.
.
Place
the
microwave
oven
on
a
stable
base.
N Oo fF WN
.
Avoid
placing
anything
on
the
top
cover
of
the
microwave
oven
that
may
interfere
with
the
exhaust
vents.
OPERATION
Air Vent
Simulated Wood
Grain Cabinet
Control Panel
Turntable
ee OO Safety Door Lock System
(Fig. 1)
‘|
NOTE
|
When
any
reference
is
made
to
pads
or
auto
sensor
cooking,
we
are
speaking
of
NE-7910,
NE-7910C.
When
any
reference
is
made
to
buttons,
we
are
speaking
of
NE-7810,
NE-7810C.
—3=

CONTROL PANEL
NOTE | Models NE-7910 and NE-7910C are ‘Atovided with a capacitive touch control panel. A push button switch control
panel is used for models NE-7810 and NE-7810C.
NE-7910, NE-7910C
NE-7810, NE7810C
Auto Sensor Cook Indicator Light Defrost Indicator Light
eel —— Clock Set Button
Digital Readout
Display Window
Power Indicator Lights
— Time Select Buttons
Clock Set Button
Digital Readout Display Window
Power Indicator Lights
Defrost Indicator Light
Timer Select Pads
Defrost Select Pad
Power
Select
Pad
Defrost
Select
Button
Auto
Sensor
Control
Pad
Power
Select
Button
Auto Sensor Cooking Guide
Reset/Stop Button
Start Pad Start Button
Reset/Stop Pad
MICROPROCESSOR CONTROL
(Fig. 2) (Fig. 3)
When the oven is first plugged in, the reset pad (reset button) should be tapped to clear the display window or
indicator lights. _ ‘
If abnormal figures appear in the display window (Example ‘‘F9 3F”) correct by removing the plug from wall
receptacle, wait 10 seconds, then reinsert the plug.
These abnormal figures may appear because of a temporary power failure or if the plug is removed and reinserted
without waiting 10 seconds.
CONTROL
A touch control is used for NE-7910, NE-7910C and a switch button control is used for NE-7810, NE-7810C.
CLOCK SET
Push Clock Set Button: The Display Window will show 00:00 and the colon will blink. Enter the time of the day (TOD) by
tapping the appropriate number pads.
Exampie: If it is 10:25 (am. or p.m.), tap 10 min. pad once, 10 sec. pad twice and 1 sec. pad 5 times. The Display
Window will show 10:25 with the coton blinking. Push the clock set button again. The colon stops blinking.
The clock is set and will keep the time of day as long as the cord is plugged in.

TOUCH SOUND
When a correct Button is pushed one beep sound is heard. If a pad is tapped and no beep sound is heard the unit has not or
cannot accept the instruction. At anytime the oven completes cooking and turns off, 5 beep sounds will be’heard.
POWERPAD | cari | |
One tap : HIGH power Four taps : M.LOW power
Two taps : M. HIGH power Five taps : LOW power
Thre: taps : MEDIUM power Six taps : WARM _ power
The following selections for 2-phase program cooking are available.
* The same power in succession * DEFROST — DEFROST
ie. | HIGH — HIGH * AUTO SENSOR to any power
Any power to Defrost
i.e. HIGH — DEFROST
TIMER PAD (Example) 18 min. 45 sec.
10 min. pad: One tap 10 sec. pad: Four taps
1 min. pad: Eight taps 1 sec. pad: Five taps
DEFROST PAD
When Defrost is selected the cycle will also program an automatic stand time equal to defrost time.
RESET/STOP PAD
Before cooking = One tap clears instructions.
During cooking : One tap temporarily stops the Cooking progress.
Another tap cancels all programs and TOD reappears in the Display Window.
OPENING DOOR
Opening the door during cooking will stop the cooking process without cancelling program. Cooking resumes as soon as the
door is closed and START pad is tapped.
AUTO SENSOR CONTROL PAD FOR NE-7910, NE-7910C
One tap : AUTO 1 Fourtaps : AUTO4
Two taps : AUTO2 Five taps : AUTO5
Three taps : AUTO3 Six taps : AUTO6

OPERATION PROCEDURE
SUMMARIZED DIRECTIONS
NE-7910, NE-7910C
NE-7810, NE-7810C
TIME COOKING : AUTO SENSOR COOKING
One-Phase cooking | Two-Phase cooking
1, Set Power. . Set Power. 1. Set Auto Sensor Control
2. Set Time. . Set Time.
. Tap START Pad. . Set second Power. 2. Touch START pad
. Set second Time
. Tap START pad
Defrost Cycle Defrost-to-Cook Cycle
1. Tap DEFROST pad. . Tap DEFROST pad.
2. Set Time. . Set Time.
3. Tap START pad. . Set second Power.
. Set second Time.
. Tap START pad.
TIME COOKING
ONE-PHASE COOKING
Step 1. Set cooking power by tapping the power pad, the appropriate number of times.
(Fig. 4)
Example: Tap Power Pad twice for M. High.
—
TOD
and
colon
disappear,
zeroes
(00
00)
appear
in
the
Display
Window.
Indicator
Light
appears
above
the
power selected,
Step 2. Set cooking time by tapping the appropriate time pads.
Example:
To
set
15
minutes
and
30
seconds,
tap
10
min.
pad
once,
1
min.
pad
5
times,
10
sec.
tap
3
times.
— The cooking time appears in the Display Window.
Step 3. Tap START pad.
— Microwave activity starts. Power Indicator light blinks.
Turntable begins to rotate. Oven lamp turns on and cooking time begins to count down.
— When cooking time has elapsed, oven beeps and turns off automatically. Microwave activity stops and power
indicator light and oven lamp turn off. Turntable stops. TOD reappears in the display window.
DEFROST
Step 1. Tap DEFROST pad.
— TOD and colon disappear. zeroes (00 00) appear in the Display Window. Defrost Indicator Light appears.
Step 2. Set defrost time by tapping Time pads. (Refer to Step 2 under One-Phase Cooking.)
— The defrost time appears in the Display Window.
Step 3. Tap START pad.
—
Microwave
activity
starts.
Oven
lamp
turns
on
and
Defrost
Indicator
Light
blinks.
Turntable
begins
to
rotate.
Defrost time begins to count down.

—
When
the
defrost
time
counts
down
to
“0”,
the
defrost
time
reappears
in
the
Display
Window.
Defrost
Indicator
Light
stops
blinking.
Microwave
activity
stops
and
oven
begins
stand
time.
—
When
the
stand
time
displayed.
counts
down
to
‘’0”,
the
oven
beeps
and
turns
off
automatically.
Oven
lamp
and
Defrost Indicator Light turn off. Turntable stops. TOD reappears in the display window.
TWO-PHASE PROGRAMMED COOKING
Step
1.
Set
first
phase
cooking
power
by
tapping
the
power
pad.
(Refer
to
Step
1
under
One-Phase
Cooking.)
—
TOD
and
colon
disappear.
Zeroes
(00
00)
appear
in
the
Display
Window.
Indicator
light
appears.
above
the
power
selected.
Step
2.
Set
first
phase
cooking
time
by
tapping
the
appropriate
Time
pads.
(Refer
to
Step
1
under
One-Phase
cooking)
—
First
phase
cooking
time
appears
in
the
Display
Window.
Step
3.
Set
second
phase
cooking
power
by
tapping
the
Power
pad.
—
First
phase
time
disappears.
Zeroes
(00
00)
appear
in
the
Display
Window.
—
Second
phase
cooking
power
indicator
light
appears
above
the
power
selected
Step
4.
Set
second
phase
cooking
time
by
tapping
the
appropriate
Time
pads.
— Second phase cooking time appears in the Display Window.
Step 5. Touch START pad.
—
Second
phase
cooking
time
disappears
and
first
phase
cooking
time
reappears
in
the
display
window
and
begins
to
count
down.
Second
phase
Power
Indicator
Light
switches
to
the
first
phase
power
and
the
indicator
light
blinks,
Oven
lamp
turns
on.
Turntable
rotates.
Microwave
activity
begins.
—
When
the
first
phase
cooking
time
has
elapsed,
second
phase
cooking
time
reappears
in
the
Display
Window
and
begins
to
count
down.
Power
Indicator
Light
shifts
to
second
phase
cooking
power
Indicator
Light
and
blinks.
—
When
second
phase.
cooking
time
has
elapsed,
beep
sounds
and
oven
turns
off
automatically.
Oven
lamp
and
Power
Indicator
Light
turn
off.
Turntable
stops.
TOD
reappears
in
the
Display
Window.
DEFROST-TO-POWER PROGRAMMED COOKING
Step
1.
Tap
DEFROST
Pad.
—
TOD
and
colon
disappear.
Zeroes
(00
00)
and
Defrost
Indicator
Light
appears
in
the
Display
Window.
Step 2. Set defrost time by tapping the appropriate Time pads.
— Defrost time appears in the Display Window.
Step 3. Set cooking power by tapping the Power pad.
—
Defrost
Indicator
Light
disappears.
Defrost
time
disappears,
Zeroes
(00
00)
appear
in
the
Display
Window.
ight selected turns ON.
Step 4. Set cooking time by tapping the appropriate Time pads.
— Cooking time appears in the Display Window.
Step 5. Touch START pad.
—
Cooking
time
disappears
and
defrost
time
reappears
and
begins
to
count
down,
Cooking
Indicator
Light
turns
off.
Defrost
Indicator
Light
turns
on
and
blinks.
Oven
lamp
turns
on.
Turntable
rotates.
Microwave
activity
starts.
—
When
defrost
time
has
elapsed,
microwave
activity
stops,
Defrost
Indicator
Light
stops
blinking.
The
defrost
time
reappears
in
the
Display
Window
and
begins
to
count
down
as
standing
time.
—
When
stand
time
has
elapsed,
cook
time
appears
in
the
Display
Window.
Defrost
indicator
light
turns
off.
Power
Indicator
Light
turns
on
and
blinks.
Cooking
time
begins
to
Bint
down.
Microwave
activity
begins.
—
When
cooking
time
has
elapsed,
beep
sounds.
Cooking
indicator
and
oven
lamp
turn
off.
Turntable
stops.
Microwave activity stops. TOD reappears in the Display Window.
pay

AUTO SENSOR COOKING ONLY ON MODELS NE-7910 AND NE-7910C
AUTO SENSOR COOK
Step 1. Put food into oven.
NOTE | For best cooking results, be sure to wrap food in a cooking bag, cover tightly with plastic wrap or glass lid.
Step 2. Set the appropriate Auto Program by tapping Auto Sensor Control Pad until desired program appears in the display
window
Onetap......... Al Four taps........ A4
Two taps........ A2 Five taps........ A5
Three taps....... A3 Six taps... . 2.00. A6
— TOD and colon disappear. The selected Auto Program appears in the Display Window. Auto indicator light
turns on.
Step 3. Touch START pad.
— Oven !amp turns on and Auto Indicator Light begins to blink.
Turntable rotates. Microwave activity starts.
— When Auto Sensor program level disappears, a time will appear in the Display Window indicating the remainder of
the cooking time.
— When the ovens’ built in auto sensor detects steam coming out from the food, the micro-computer calculates the
balance of the cooking time. The displayed auto program indication (A2, for example) disappears and the rema-
ining cooking time automatically appears in the display window and starts to count down.
— When the time displayed counts down to 0, the beep sounds and the oven turns off automatically. Microwave
activity stops and the oven lamp and auto indicator light turn off. Turntable stops. The display window
indicates the TOD. ;
A remainder of calculated cooking time appears only with the A2 to AG settings. With A1 setting, the oven will shut
off immediately when the auto sensor detects steam from the food.
When the oven calculates the balance of cooking time to be over 60 minutes, the time will appear as hours and
minutes. )
Example: If the time should be 94 minutes, the Display Window will show 1 H 34. The seconds will not visibly count
down in the Display Window until the 34 minutes has elapsed and only 60 minutes remain. At that time the
unit will again show minutes and seconds. Seconds will now visibly count down.
1. Do not interrupt the auto sensor cooking cycle until time appears in the display window.
2. All foods must be at refrigerator temperature (38° ~ 42°F) for auto sensor cooking.
3. Before using auto sensor feature, make sure glass tray in the oven is dry to assure best auto cooking results.
4, Room temperature or heat surrounding the oven should not be above 95°F (35°C) when using the auto sensor cooking
cycle. Inaccurate cooking may result.
5. Foods less than 3 or 4 ounces should be cooked by power and time, not by the auto sensor cooking cycle.
AUTO COOK TO WARM CYCLE
Step 1. Put food into oven.
— See NOTE Under Step 1 in Auto Sensor Cooking.
Step 2. Set the appropriate Auto Program by tapping Auto Sensor Control pad.
— TOD and colon disappear. The selected Auto Program, A2 for example, appears in the Display Window. Auto
Indicator Light turns on.

Step 3. Set Warm Power by tapping Power pad 6 times.
— Auto Program indication (A2, for example) disappears. Auto Indicator Light goes off and Warm power indicator
light turns on.
Step 4. Set Warming time by tapping Time pads.
— Warming time selected appears in the display window.
Step 5. Touch Start pad.
— Warm power Indicator Light goes off and Auto Indicator Light turns on and blinks. Warming time disappears
and Auto Program (A2, for example) reappears. Oven lamp turns on. Turntable rotates. Microwave activity
begins.
— When Auto Sensor Cooking is over, Auto Indicator Light turns off, Warm power Indicator Light comes on and
blinks. Warming time appears in the display window and begins to count down.
— When warming time has elapsed the oven beeps and shuts off automatically. Microwave activity stops. Turntable
stops. Oven lamp turns off and TOD reappears in the display window.
TIME/DELAY START
TIMER This models’ digital display window can be used as a timer in the following manner:
Step 1. Set the desired time by tapping Time pads.
— TOD AND colon disappear and the selected time appears in the Display Window.
Step 2, Touch START pad.
— The time displayed simply counts down, as a digital timer would. No microwave activity begins.
Turntable does not rotate. No lights appear.
— When time has elapsed, oven beeps. TOD reappears in the Display Window.
DELAY START This oven can delay the start of any cooking function by up to 99 minutes and 99 seconds.
Step 1. Set the length of time you would like to delay the start of cooking, defrosting, or auto sensor cooking.
— TOD and colon disappear and the delay time selected appears in the Dispay Window.
Step 2, Set Power and time for Cook, or Defrost, or Select Auto Sensor Control for Auto Cooking cycle.
NOTE jIt is not possible to use the delay feature for 2 phase cooking. For example Delay-Auto Cook-Warm cycle. In other
words the three stage program cannot be accepted. ‘’E”’ indicating error will appear in the display window, if these
selections are chosen.
Step 3. Touch START pad.
— 2nd phase cooking selection disappears and the delay time reappears in the Display Window and starts to count
down. No microwave activity begins. Turntable does not rotate. No lights appear.
-— When delay time has elapsed, oven automatically enters seccnd programmed cycle.
— When cooking cycle is over, oven {amp and the power indicator light turn off. Turntable stops. TOD reappears in
the Display Window.
CHECKING PROCEDURE ON OPERATION
Instructions relating to Auto Sensor Cooking are only for NE-7910, NE-7910C.
1. If “E” indication appears in the Display Window:
You might have given wrong instruction. Touch “RESET” pad to clear and give new instructions from the beginning.
“E’’ indicating ERROR, appears under following conditions.
e When Auto Sensor Cooking is selected after Power/Time cooking is selected.
« When Auto Sensor Cooking is selected after Defrost/Time is selected.
—~9—

« When Defrost is selected after Auto Sensor Cooking is selected.
e When 3rd stage cooking is selected.
e When clock is set later than 12:59 or at impossible time like 00:73 or 83:25.
Touch RESET Pad to clear “‘E” from Display Window and enter correct instructions.
2.
© MNOS &
10.
11.
12.
lf Auto Sensor Control should not work properly, oven is designed to shut off automatically 60 minutes after operation
begins and to show “FFFF” in the Display Window. Touch RESET pad and complete the cooking by power and time.
If auto sensor control is open the oven will shut off automatically approximately 15 seconds.
—
AutoC@
Defrost !
Power C> OQ (am) OQ oO
High M.High Med M.Low Low Warm
Autoc>
Defrost >
Power'C>) Oo oO
High “Hi M.Low Low
(Fig. 5)
CAUTION WHEN USING
. Do not use metalware
In rare cases where you must use metal materials such as foil or skewers, etc., take care not to have the edge of the metal
material touch the inner glass screen, or the oven walls (coated steel), because the glass plate may be broken the coated
part may be burned by sparking.
Always keep the glass cooking tray clean
Do not cook foods with a high fat or sugar content directly on the glass tray.
. Do not dry clothes in the microwave oven.
. Avoid using wooden containers for more than a few seconds.
Do not operate the oven with a kitchen towel or a napkin left between the door and the front wall of the oven.
Do not press the cook button when the oven is empty.
Keep the inside of the oven clean.
Avoid cooking a small-volume of food for a long period of time.
If any visible steam or moisture is found on or around the door just wipe it off. There is no need for concern and this
never causes any microwave leakage.
Cautions when operating the control panel.
A. Do not touch contro} pads with water or oii on your finger.
When the control panel is dirty, wipe with a damp cloth first and then finish with a soft dry cloth. Do not use harsh
detergents or abrasives.
B. Do not try to touch the pads while wearing gloves or while holding any insulating materials.
C. For most accurate programming of the unit, tap the center of each pad or push the center of each button firmly.
D. Do not hit or strike the control panel since this is made of glass and may be broken.
When removing the roller-ring from. turntable for cleaning, be sure to re-install into the proper position. Avoid exposing
your watch to the magnetic-capsules located on the bottom of the turntable, or your watch may be damaged.
When power select is set at a setting other than High, the intensity of the oven lamp will vary. This is normal and
indicates that the oven is operating normally.
—~10—

SCHEMATIC DIAGRAM
The
figure
below
shows
the
schematic
diagram
for
model
NE-7910,
NE-7910C,
NE-7810
and
NE-7810C.
r
NOTE: DOOR IS CLOSED.
= GROUND
zz CHASSIS
DIODE CURRENT
THERMAL CUTOUT (x2) 12}
(MAGNETRON)
(OVEN)
POWER
SOURCE
(V
AC l15V
60Hz
-s
uf---
PLUG
{ LATCH. |
~ SWITCH B
(SECONDARY)
AC
HIGHVOLTACE jf
DIGITAL TRANSFORMER
PROGRAMMER
UNE
EE
CIRCUIT
_
IMPORTANT
SAFETY
NOTE:
THE
SHADED
AREA
ON
THIS
SCHEMATIC
DIAGRAM
INCORPORATES
SPECIAL
FEATURES
IMPORTANT
FOR
PROTECTION
FROM
MICROWAVE
LEAKAGE.
FIRE
AND
ELECTRICAL
SHOCK
HAZARDS.
WHEN
SERVICING
IT
tS
ESSENTIAL
THAT
ONLY
MANUFACTURERS
SPECIFIED
PARTS
BE
USED
FOR
THE
CRITICAL
COMPONENTS
IN
THE
SHADED
AREA
OF
THE
SCHEMATIC
DIAGRAM.
WHITE BLACK
: WIRING DIAGRAM
ey
oe
“
|
SYMBOL
|
=
Po")
(ata
|
Te
LATCH
a
5
i
HA
BA
SWITC
OR
"a
g
LATCH
SWITCH
B
B
2
POWER
RELAY
}
R
|
RED
as
:
W
_
WHITE
A
INDICATES
OR
W__|
ORANGE-WHITE
HARNESS
LEAD
SHORT SENSOR ELEMENT SHIELD WIRE LEAD
SWITCH (NE-7910, NE-7910C ONLY)
(Fig. 7)
NOTE
|
When
reference
is
made
to
pads
or
auto
sensor
cooking,
we
are
speaking
of
NE-7910,
NE-7910C.
When
reference
is
made
to
buttons,
we
are
speaking
of
NE-7810,
NE-7810C.
-11—

CIRCUIT DESCRIPTION
Refer to the schematic diagram on page 11.
1.
{A}
(B)
{C)
(A)
(B)
(C)
(A)
(B)
(C)
(A)
(B)
{C)
(D)
(E)
When the food is placed inside the oven and door is closed.
The low voltage transformer supplies the necessary voltage to the digital programmer circuit when power cord is
plugged in. se
The contacts of the short switch open. This switch creates short circuit to blow 15 A fuse and stop magnetron oscilla-
tion when door is opened during operation under abaornial condition, {i.e. both the contacts of latch switch A and B
do not open the circuit to stop oscillation.)
The door keyes are caught by the door hooks, the contacts of latch switch A and B close the primary circuit.
When cooking power and cooking time are set by tapping the power pad (button) and the desired
numerical pads (buttons).
Power indicator light turns on to indicate that power has been set.
The time you set appears in the display window.
The digital programmer circuit memorizes the functions set.
When auto sensor cooking is set by tapping the auto sensor contro! pad.
Auto indicator light turns on.
The selected auto program appears in the display window.
The digital programmer circuit memorizes the information that the auto sensor cooking has been set.
When the start pad (button) is tapped.
115V A.C. is applied to the high voltage transformer through power relay which is energized by the digital programmer
circuit.
Fan motor starts rotating and cools the magnetron by blowing the air coming from the intake on the back panel over
the magnetron fins. Also the fan motor drives the turntable by means of gears, belts and pulleys for uniform cooking.
(See fig. 8)
Fan motor
MAGNET POLARITY
Turntable Magnet
Ee
Pulley D
Oven bottom wail
(Fig. 8)
The oven lamp turns on.
Power (or defrost, auto indicator) indicator light selected starts blinking to indicate magnetron oscillation.
20V A.C. is supplied to the digital programmer circuit from the high voltage transformer.
=12—

(F)
3.2
volts
AC
is
generated
from
the
filament
winding
of
MAGNETRON
the
high
voltage
transformer.
This
3.2
volts
is
applied
to
the
magnetron
to
heat
the
magnetron
filament
through
two noise preventing choke coils.
(G) A high voltage of 2,800 volts AC is generated in the
i
VARIABLE
secondary
of
the
high
voltage
transformer
and
this
seco-
POWER
SWITCH
ndary voltage is increased by the action of the diode and
the charging of the high voltage capacitor. This resultant
DC voltage is then applied to the anode of the magne
tron. As shown in fig. 9, the first half cycle of the high
voltage produced in the high voltage transformer seco-
ndry charges the high voltage capacitor.
Current
flow
is
in
the
direction
of
the
dotted-line
-----
>.
HIGH-VOLTAGE
TRANSFORMER
During the second half cycle, the voltage produced by
the
transformer
secondary,
and
the
charge
of
the
high
(Fig.
9)
voltage
capacitor
are
combined
and
applied
to
the
magnetron
as
shown
by
the
solid-line
——+
so
that
oscillation
begin.
The
disturbance
wave
generated
by
the
magnetron
is
prevented
by
the
choke
coils
of
1.6H,
filter
capacitors
of
500pF
and the magnetron’s shielded case so that TV and radio programs are not impaired by noise.
(H)
The
coil
of
variable
power
switch
is
energized
intermittently
by
the
digital
programmer
circuit,
when
the
oven
is
set
at
any
power
selection
except
for
High
power
position.
The
digital
programmer
circuit
controls
the
ON-OFF
time
of
the
variable
power
switch
contacts
in.order
to
vary
the
output
power
of
the
microwave
oven
from
“warm”
to
“high’’
power.
One
complete
ON
and
OFF
cycle
of
the
variable
power
switch
is
22
seconds.
The
relation
between
indications
on
the
contro!
panel
and
the
output
of
the
microwave
oven
is
as
follows:
OUTPUT
POWER
AGAINST
ON,
OFF
TIME
ON
HIGH
POWER
VARIABLE
POWER
SWITCH
22(S) —— 2215
ON ON
20(S}
C—O
M.
High
|
20
/
22
(
91%)
ON
OFF
ON
OFF
15(S).
Med
15
/
22
(
68%)
ON
lorr
|
ON
lore]
INDICATION
High 22 / 22 (100%)
14S
M. Low 11/22 ( 50%) ON | FF f ON | ofr |
}.
oO
6(S)
Low
6/22
(
27%)
[ox]
OFF
fox]
OFF
|
2(S)
Warm
2/22
(
10%)
[ox
OFF
ON
OFF
Defrost 7/22 ( 32%)
(1) | The cooking time shown in the display starts to count down.
—~13—

{A)
{B)
(C)
{D)
(E)
(F)
(G)
(A)
(B)
(C)
(D)
When
the
door
is
opened
during
cooking,
Latch
switch
A
(primary)
and
latch
switch
B
(secondary)
open
to
cut
off
the
primary
voltage
to
the
high
voltage
transformer
to
stop
microwave
oscillation.
Power
indicator
(or
auto,
defrost
indicator)
light
stops
blinking
and
display
stops
counting
down.
Power relay stops functioning,
HIGH-VOLTAGE
Oven
lamp
turns
off.
TRANSFORMER
Fan motor and turntable stop rotating.
As
soon
as
the
door
handle
button
is
pressed,
the
short
switch
contacts
close
and
create
the
short
circuit.
If
the
contacts
of
latch
switch
A
and
the
contacts
of
latch
switch
B
both
malfunction,
the
15A
fuse
blows
(PRIMARY}
LATCH
SWITCH A
open
due
to
the
large
current
surge
caused
by
the
short
“
. +
. 7
OD
switch
activation,
and
this
in
turn
stops
magnetron
15A
FUSE
LATCH
SWITCH
B
oscillation, (SECONDARY)
:
(Fig.
11)
When
the
reset/stop
pad
(button)
is
tapped
once
_ during cooking.
The
digital
programmer
circuit
cuts
the
D.C.
voltage
being
supplied
to
the
power
relay
coil
causing
the,
magnetron
to
stop
oscillation.
Power
indicator
(or
auto,
defrost
indicator)
light
stops
blinking
and
stays
on.
Oven lamp turns off.
Fan motor and turntable stop rotating.
NOTE
|At
this
moment,
the
oven
is
in
“hold”
condition
and
when
the
start
pad
(button)
is
tapped
again,
the
oven
starts
to
(A)
(B)
(C)
(D)
(E)
operate as originally programmed.
When
the
reset/stop
pad
(button)
is
tapped
twice
during
cooking.
The
digital
programmer
circuit
cancels
all
instructions
you
gave.
Power
relay
stops
functioning
to
stop
the
magnetron
oscillation.
Power
indicator
(or
auto,
defrost
indicator)
light
turns
off
and
the
display
window
shows
the
TOD.
Oven
lamp
turns
off.
Fan motor and turntable stop rotating.
—14—

PRECAUTIONS
TO
BE
OBSERVED
BEFORE
AND
DURING
SERVICING
TO
AVOID
POSSIBLE
EXPOSURE
TO
EXCESSIVE
MICROWAVE
ENERGY
(A) Do not operate or allow the oven to be Operated with the door open.
(B)
Make
the
following
safety
checks
on
all
ovens
to
be
serviced
before
activating
the
magnetron
or
other
microwave
source,
and
make repairs
as
necessary:
(1) Interlock operation
(2) Proper door closing
(3) Seal and sealing surfaces: (arcing, wear, and other damage)
(4) - Damage to or loosening of hinges and latches
(5) Evidence of dropping or abuse
(C)
Before
turning
on
microwave
power
for
any
service
test
or
inspection
within
the
microwave
generating
comparments,
check
the
magnetron,
wave
guide
or
transmission
line,
and
cavity
for
proper
alignment,
integrity
and
connections.
(D)
Any
defective
or
misadjusted
components
in
the
interlock,
monitor,
door
seal,
and
microwave
generation
and
transmis-
sion
systems
shall
be
repaired,
replaced,
or
adjusted
by
procedures
described
in
this
manual
before
the
oven
is
released
to
the owner.
(E)
A
microwave
leakage
check
to
verify
compliance
with
the
Federal
performance
standard
should
be
performed
on
each
oven prior to release to the owner.
CAUTIONS TO BE OBSERVED WHEN ‘TROUBLESHOOTING
Unlike many other appliances, the microwave oven is high-voltage, high-current equipment. Though it is free
from danger in ordinary use, extreme care should be taken during repair.
PACEMAKER
WEARERS
MUST
CONSULT
THEIR
PHYSICIAN
BEFORE
ATTEMPTING
SERVICE.
SERVICEMEN SHOULD REMOVE THEIR WATCHES WHENEVER WORKING CLOSE TO OR REPLACING
THE MAGNETRON.
1. Check the grounding
Do not operate on a 2-wire extension cord. The microwave oven is designed to be used when grounded, It is impera-
tive, therefore, to make sure it is grounded properly before beginning repair work.
2. Warning about the electric charge in the high
voltage capacitor
For about 30 seconds after the oven stops, an electric
charge remains in the high voltage capacitor. When
replacing or checking parts, short between capacitor
terminals by an insulated screw driver to discharge. See
figure 12.
CAPACITOR __ =
q
Fig. 12
—15—
(Fig.
12)

THERE
JIS
HIGH-VOLTAGE
PRESENT,
WITH
HIGH-CURRENT
CAPABILITIES
IN
THE
CIRCUITS
OF
THE
HIGH
VOLTAGE
TRANSFORMER
SECONDARY
AND
FILAMENT
TRANSFORMER
SECONDARY.
IT
IS
EXTREMELY
DANGEROUS
TO
WORK
ON
OR
NEAR
THESE
CIRCUITS
WITH
THE
OVEN
ENERGIZED.
NEVER
TOUCH
ANY
CIRCUIT
WIRING
WITH
YOUR
HAND
OR
INSULATED
TOOL
DURING
OPERATION.
DO
NOT
TOUCH
ANY
PART
OF
THE
CIRCUITRY
ON
THE
DIGITAL
PROGRAMMER
CIRCUIT,
SINCE
A
STATIC
ELECTRIC
DISCHARGE
MAY
DAMAGE
THIS
CONTROL
PANEL.
DO
NOT
TOUCH
FILTER
CAPACITOR
ON
THE
TOUCH
CONTROL
CIRCUIT.
THERE
IS
50
VOLTS
OR
MORE
PRE-
SENT,
WHILE
POWER
SUPPLY
CORD
IS
PLUGGING
IN.
3.
When
parts
must
be
replaced,
remove
the
power
plug
from
the
outlet.
4.
When
the
15
Amp
fuse
is
blown
due
to
the
operation
of
short
switch:
(A)
Replace
the
latch
switch
A
(primary),
latch
switch
B
(secondary)
and
short
switch.
This
is
mandatory.
Refer
to
pages
21
and
22
for
the
necessary
adjustments
for
these
switches.
(B)
When
replacing
the
fuse,
confirm
that
it
has
the
appropriate
rating
for
this
model.
5.
Avoid
inserting
nails,
wire,
etc.
through
any
holes
in
the
unit
during
operation.
Never
insert
a
wire,
nail
or
any
other
metal
object
through
the
lamp
holes
on
the
cavity
or
any
other
holes
or
gaps,
because
such
objects
may
work
as
an
antenna
and
cause
microwave
leakage.
6.
Pacemaker
wearers
should
consult
their
physician
before
attempting
to
service
or
repair
a
microwave
oven.
For
additional
information
on
this
subject,
write
to:
the
manufacturer
of
your
pacemaker.
7. Confirm after repair
(A)
After
repair
or
replacement
of
parts,
make
sure
that
the
screws
of
the
oven,
etc.
are
neither
loose
nor
missing.
Microwaves
might
leak
if
screws
are
not
properly
tightened.
(B).
Make
sure
that
all
electrical
connections
are
tight
before
inserting
the
piug
into
the
wall
outlet.
{C)
Check
for
radiation
leakage.
(Refer
to
procedure
for
measuring
radiation
leakage
on
pages
23,
24
&
25.
_. ‘DISASSEMBLY AND PARTS REPLACEMENT PROCEDURE
1, Removal-of outer panel: ~
Remove
the
seven
screws
from
the
front
section
and
the
seven
screws
from
the
rear
section.
The
outer
panel
can
now
be lifted off.
—16—

2.
Replacement
of
the
magnetron
for
NE-7910,
NE-7910C,
NE-7810
and
NE-7810C
CAUTION
SERVICEMEN SHOULD REMOVE THEIR WATCHES WHENEVER WORKING CLOSE TO OR REPAIRING THE
MAGNETRON :
w
(B)
Remove the magnetron with the shielded case, permanent. magnet, choke coils and 500pF capacitors because they are
one assembly. . = :
Discharge the high voltage capacitor, (See page 15)
Remove air guide.A by removing the 2 screws holding it to the oven cavity.
Remove two high voltage leads from filament terminals. .
Remove two screws holding thermal cutout to magnetron.
Remove four screws holding the magnetron to waveguide.
NOTE;
A
Make
sure
that
the
embossed
ring
is
rigidly
attached
on
the
magnetron
anode,
(Fig.
14)
a
B
~°To
prevent
microwave
leakage,
tighten
the
mounting
screws
properly
making
sure
there
in
no:
gap
between. the waveguide and the magnetron.
° ff \
i —
MAGNETRON
(Fig. 14)
NOTE
|
Be
sure
to
ground
any
static
electric
charge
in
your
body
before
handling
the
digital
programmer
circuit.
ie
Disconnect 10-pin connector and 2-pin connector.
Unsolder
four
lead
wires
connected
to
terminals
on
the
humidity
sensor.
and:remove
two
screws
holding
humidity
sensor
to
the
oven
cavity.
(See
fig.
16)
a
m
NOTE
A
When
replacing
the
digital
programmer
circuit,
you
must
unsolder
the
two
wires
from
the
humidity
sensor.
Never
unsolder
the
wires
from
the
digital
programmer
circuit
board
itself...
B
When
reconnecting
the
two
wires
to
the
humidity
sensor,
follow
the
wiring
of
the
sensor
on
page
11
of
this service manual. :
Remove three screws holding the digital programmer circuit to the escutcheon base, (See fig. 15)
Remove 8 screws holding the digital programmer circuit to the escutcheon base. (See fig. 17)
NOTE
|
A
Remove
two
screws:holding
the
low
voltage
transformer
to
new
P.C.B.
before
installing
the
new
one
to
escutcheon base.

4,
(A)
(B)
(C)
SENSOR ELEMENT
&
J
5
=
=
ti
will ut
NT a0 a0
1 wit
8
LOW VOLTAGE
TRANSFORMER
(Fig. 17)
. (Fig. 16)
Replacement
of
the
digital
programmer
circuit
for
NE-7810
and
NE-7810C
Remove two connectors.
Remove
two
screws
holding
the
escutcheon
base
with
the
digital
programmer
circuit.
Remove
eleven
screws
holding
the
digital
programmer
circuit
to
the
escutcheon
base,
NOTE
|
A
_
Remove
two
screws
holding
the
low
voltage
transformer
to
new
P.C.B.
before
installing
the
new
one
to
escutcheon.
When
connecting
2-pin
connector,
orange
lead
wire
will
be
connected
to
black
leadwire
and
black
to
orange. This is normal.
DIGITAL
PROGRAMMER
CIRCUIT
LOW VOLTAGE
TRANSFORMER
(Fig. 19)
(Fig. 18)
_18—

(A)
(B)
(C)
(D)
(E)
(F)
(G)
6.
ae
a hn eet
Following illustration shows the high voltage wiring.
Replacement of the fan motor assembly.
Remove the variable power switch and the high voltage capacitor.
Remove 5 screws holding fan motor bracket.
Pull the fan motor with the bracket and gear box toward you.
Remove the belt from fan motor’s pulley.
Remove three screws holding the fan motor assembly.
Remove the wire pin to remove pulley.
NOTE
|
When
installing
the
pulley
A
to
shaft
of
fan
motor,
the
pulley
A
should
be
positioned
on
the
hole
at
shaft
end and be fixed by wire pin, Otherwise the belt may be detached from the pulley while operating.
eS
VARIABLE
POWER
SWITCH
(Fig. 20) (Fig. 21)
High voltage circuit wiring.
| Magnetron |
White
Insulation tube
Filamet lead wire
High-voltage \
capacitor
High-voltage
ransformer i — .
Tras Diode and Varistor
10 @ Resistor Green ground lead
wire
—19—
Remove the rubber belt from pulley C and put it on the base with the other end of belt being caught on pulley D.
(Fig. 22)
(Fig. 23)

(A)
(B)
(C)
(B)
(C)
Replacement of the door assembly.
Remove the 4 bolts holding the upper hinge and lower hinge to the oven assembly.
Open the door and while pulling the door toward you, work the upper hinge out through the hole in the oven assembly.
The door will be simply lifted off the bottom hinge pin at the same time.
When
mounting
the
door
assembly
to
the
oven
assembly,
be
sure
to
adjust
the
door
assembly
parallel
to
the
sash
by
moving
the
upper
hinge
and
lower
hinge
according
to
the
directions
in
fig.
24.
Also
adjust
so
that
the
door
has
no
play
between the inner door surface and oven frame assembly.
If
the
door
assembly
is
not
mounted
properly,
microwaves
may
leak
from
the
clearance
between
the
door
and
the
oven.
(Fig. 24) 7a 25)
MEASUREMENT AND ADJUSTMENT
NOTE | Please note on models NE-7910, NE-7910C, NE-7810 and NE-7810C, test DIODE CURRENT not ANODE
CURRENT.
NOTE
|
When
you
measure
diode
current
because
of
a
no
oscillation
complaint,
check
the
diode
first.
If
the
diode is shorted, do not measure the diode current. Otherwise 102 resistor will be burnt by AC current.
Measurement and adjustment of the diode current
After replacement of the high voltage transformer, high voltage capacitor or the magnetron, measure the diode current
of the magneton according to the following procedures.
To measure the diode current of the magnetron, do not use an ammeter, use the DC 5V or DC 10V range of a
voltmeter.
As shown in fig.26 remove the jumper connected to the @ side of the 102 resistor, insert the meter probes into both
resistor terminal holes being careful to observe the correct polarity, and press the cook start button. After taking the
measurement, reconnect the jumper to the G@) side of the 102 resistor.
To determine the diode current, use this formula:
a Meter indicated voltage (V)
Diode Current (mA) =- x 1000
10 (Q)
Diode current, under normal conditions, is 300420mA with the power on the “‘High”’ power selection. But it may
change, as shown in fig.27 depending on ‘the power source voltage.
After replacement of the parts, make sure the diode current is within the range of 300£20 mA.
—~20~—