Panasonic NN-S781 Quick start guide

Panasonic Microwave Oven
QPQ
Australia
BF WF SF
NN-S781 
NN-S761 
NN-S751 
NN-T791 
PART NO. 541204 MICROWAVE OVEN NN – T791SF QPQ
Specifications NN-S781 NN-S761 NN-S751 NN-T791
Power Source: 230V-240V AC Single Phase, 50Hz
Power Requirement: 1040W 1040W 1040W 1040W
Output (IEC705-88): 1200W 1200W 1200W 1200W
Microwave Frequency: 2450MHz
Timer: 30 min. / Stage (HIGH Power) -- 5 Stage Maximum
90 min. 99 sec. / Stage (Other Power Levels) - 5 Stage Maximum
Outside Dimensions: 21 7/8"(555mm)(W) x 19 9/16" (497mm)(D) x 11 15/16” (301 mm)(H)
Oven Cavity Dimensions: 16 7/16"(418mm)(W) x 18 1/2" (470mm)(D) 9"(228mm) (H)
Weight: 36 lbs / 16.5kg
Output power: IE 705-88 Test Procedure
Specifications subject to change without notice.
599251

MANUAL 599251
2

MANUAL 599251
3
WARNING
This service information is designed for experienced repair technicians only and is not designed for use by the
general public. It does not contain warnings or cautions to advise non-technical individuals of potential dangers in
attempting to service a product.
Products powered by electricity should be serviced or repaired only by experienced professional technicians. Any
attempt to service or repair the product or products dealt with in this service information by anyone else could
result in serious injury or death.
WARNING
1. This product should be serviced only by trained, qualified personnel.
2. Check for radiation leakage before and after every servicing according to the "procedure for measuring
radiation leakage." 3. If the unit cannot be repaired on site, advise the customer not to use until unit is
repaired.
4. There are special components used in the microwave oven which are important for safety. These parts
are marked with a Lon the replacement parts list. It is essential that these critical parts should be
replaced only with the manufacturer's specified parts to prevent microwave leakage, shock, fire, or other
hazards. Do not modify the original design.
When troubleshooting or replacing parts, please refer to the country identifications shown below for your
applicable product specification.
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
(D) Any defective or mis-adjusted components in the interlock, monitor, door seal, and microwave generation
and transmission 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.

MANUAL 599251
4
DANGER OF HIGH VOLTAGE AND HIGH TEMPERATURE (HOTILIVE) OF THE INVERTER POWER SUPPLY
(U)
INVERTER WARNING
This Inverter board looks like a regular PCB. However, this PCB drives the magnetron tube with extremely high
voltage and high current.
NEW HV
IT HAS
1. Very high voltage and high current circuits.
It functions the same as the high voltage transformer and high voltage capacitor in ordinary microwave
ovens.
2. Aluminium heat sink is energised with very high voltages and high heat energy.
3. Very high voltage may remain in circuitry even when oven is off. High voltage may remain in the
capacitors on the board.
DO NOT:
1. Do not touch circuitry because it has very hot (high voltage) circuitry. Even when replacing board,
extreme care should be taken to avoid possible electric shock hazards. High voltage may remain in circuit.
2. Do not touch aluminium heat sink because it is very hot in high voltage and also very hot in high heat
energy.
3. Do not try to adjust or tamper with preset volume on the inverter board because it is very dangerous to
adjust without proper test equipment.
4. Do not test oven while inverter grounding plate or screws are Ioose. It is very dangerous to operate H.V.
Inverter Circuit (U) with loose mounting screws or if improperly grounded.
5. For USA only:
Do not try to repair Inverter PCB because it is very dangerous to repair it. Replace as whole High Voltage
Inverter Circuit unit and return fully re-packed with original shipping box and shipping materials.
INVERTER POWER SUPPLY

MANUAL 599251
5

MANUAL 599251
6
SCHEMATIC DIAGRAM – (QPQ)

MANUAL 599251
7
TABLE (1L-1min. test)
RATED OUTPUT TEMPERATURE RISE
1200W(IEC705-88) Min. 18.5oF (10.3oC)
MEASUREMENTS AND ADJUSTMENTS
WARNING
¾For continued protection against radiation hazard,
replace only with identical replacement parts (For
touch models Part No. A6142-1450, Type No. V-
16G-3C26-M for Primary latch switch Part No.
A61425180AP, Type No. L-3C2-2 for Secondary
latch switch and Part No. A61785180AP, Type No.
L-2C2-2 for short switch.)
¾When the 10 Amp. fuse is blown due to the operation
of the short switch, you must replace primary latch
switch and short switch. Also replace power relay B
(Part.No. AEG5J1 EG12BIAEG5Jl EG18B, Type No.
G5J-1-TP) when the continuity check reads shorted
contacts (1-2). Then follow the adjustment
procedures below.
Interlock switch replacement - In replacing faulty
switches, be sure mounting tabs are not bent, broken or
otherwise deficient in their ability to hold the switches.
¾Refer to schematic diagram to ensure proper
connection
1. Adjustment of Primary latch switch,
Secondary latch switch and Short switch.
(A) When mounting Primary latch switch,
Secondary latch switch and short switch
to door hook assembly, mount the Primary latch switch, the Secondary latch switch and the short
switch to the door hook assembly as shown in table.
NOTE: No specific adjustment during installation of Primary latch switch, Secondary latch switch and short
switch to the door hook is necessary.
(B) When mounting the door hook assembly to the oven assembly, adjust the door hook assembly by
moving it in the direction of arrow in the illustration so that the oven door will not have any play in
it. Check for play in the door by pulling the door assembly. Make sure that the latch keys move
smoothly after adjustment is completed. Completely tighten the screws holding the door hook
assembly to the oven assembly.
(C) Reconnect the short switch and check the continuity of the monitor circuit and all latch switches
again by following the components test procedures.
2. Measurement of microwave output
The output power of the magnetron can be determined by performing IEC standard test procedures.
However, due to the complexity of IEC test procedures, it is recommended to test the magnetron using the
simple method outlined below.
Necessary Equipment:
*1 litre beaker, *Glass thermometer, *Wrist watch or stopwatch
NOTE: Check the line voltage under Ioad. Low voltage will lower the magnetron output. Take the temperature
readings and heating time as accurately as possible. (A) Fill the beaker with exactly one litre of tap water. Stir the
water using the thermometer and record the beaker's temperature. (recorded as T1).

MANUAL 599251
8
(B) Place the beaker on the centre of glass cook plate. Set the oven for High power and heat it for
exactly one minute.
(C) Stir the water again and read the temperature of the beaker (recorded as T2).
(D) The normal temperature rise at High power for each model is shown in the table.

MANUAL 599251
9
PROCEDURE FOR MEASURING MICROWAVE ENERGY LEAKAGE
WARNING
Check for radiation leakage after every servicing. Should
the leakage be more than 2mW/cm2after repairing or
replacing any radiation safety device, keep a written
record for future reference, the leakage reading must be
recorded on the service repair ticket while in the
customer's home.
1. Equipment
Electromagnetic radiation monitor
Glass thermometer 212 °F or 100 °C
600cc glass beaker
2. Procedure for measuring radiation leakage.
Note before measuring.
(1) Do not exceed meter full scale deflection.
Leakage monitor should initially be set to the
highest scale.
(2) To prevent false readings the test probe
should be held by the grip portion of the handle
only and moved along the shaded area in Figure
no faster than 1 inch/sec (2.5cm/sec).
(3) Leakage with the outer panel removed ......
less than 5mW/cm2
(4) Leakage for a fully assembled oven with door
normally closed ...... less than 2mW /cm21mW
/cm2for Canada).
(5) Leakage for a fully assembled oven [Before
the latch switch (primary) is interrupted] while
pulling the door ...... less than 2mW /cm2.
WARNING
AVOID CONTACTING ANY HIGH VOLTAGE PARTS.
MOVE PROBE ALONG SHADED
AREA (/////////) AROUND EXHAUST
OPENINGS (as shown) AND AROUND
AIR INLET OPENING.
(A) Pour 275 + 15cc (9oz + 1/2oz) of 20° + 5 °C (68° ± 9°F) water in a beaker which is graduated to 600cc,
and placed in the centre of the oven.
(B) Set the radiation monitor to 2450MHz and use it following the manufacturer's recommended test procedure to
assure correct results.
(C) When measuring the leakage, always use the 2 inch (5cm) spacer supplied with the probe.
(D) Tap the start pad or set the timer and with the magnetron oscillating, measure the leakage by holding the
probe perpendicular to the surface being measured.
(1) Measurement with the outer panel removed.
Whenever you replace the magnetron, measure for radiation leakage before the outer panel is installed
and after all necessary components are replaced or adjusted. Special care should be taken in measuring
around the magnetron.

MANUAL 599251
10
WARNING: Avoid contacting any high voltage parts.
(2) Measurements with a fully assembled oven.
After all components, including outer panel are fully assembled, measure for radiation leakage around the
door periphery, the door viewing window, the exhaust opening and air inlet openings,
(3) Record keeping and notification after measurement
After any adjustment or repair to a microwave oven, a leakage reading must be taken. Record this
leakage reading on the repair ticket even if it is zero.
A copy of this repair ticket and the microwave leakage reading should be kept by repair facility.
4. At least once a year, have the radiation monitor checked for calibration by its manufacturer.

MANUAL 599251
11
EXPLODED VIEW

MANUAL 599251
12
PARTS LIST
NOTE:
1: When ordering replacement part(s), please use part number(s) shown in this part list. Do not use
description of the part.
2: Important safety notice.
Components identified by mark have special characteristics important for safety. When replacing any of
these components use only the manufacturer’s specified parts.
NOTE: “A” parts are supplied by MOD (Japan)
“F” parts are supplied by SIMMC (China)
Ref.No. Part number Part name & description Pcs/ Set Remarks
1 F0006810OHN CAUTION LABEL 1
4 F10014W00AP BASE 1
5 F10084T00AP RUBBER FOOT 4
6 F110D4W00BQP CABINET BODY (U) 1 S761BF, S751BF, T791SF
6 F110D4W00HQP CABINET BODY (U) 1 S781WF, S761WF, S751WF
7LF200A4W00AP OVEN (U) 1 S781WF, S761BF/WF, T791SF
7LF200A4W30AP OVEN (U) 1 S751BF/WF
8 F20554W00AP COVER
9 F21314W00AP PULLEY SHAFT 1
10 F2177-F80 WASHER 1
11 B290D9330AP ROLLER RING (U) 1
12 LF3020-1200 DOOR HOOK 1
14 F3136-1200 HOOK LEVER A 1
15 F31374650AP HOOK LEVER B 1
16 F31384650AP HOOK LEVER C 1
17 F400A4T10QP FAN MOTOR 1 AC240V, SINGLE PHASE, 50Hz
18 F40084T00AP FAN BLADE 1
19 F40254W00AP AIR GUIDE A 1
20 F40264W00AP AIR GUIDE B 1
21 F41444W00AP ORIFICE 1
22 F64505540AP SENSOR COVER B 1 S781WF, S761BF/WF, T791SF
23 F65435540AP SENSOR COVER C 1 S781WF, S761BF/WF, T791SF
24 F65434W00AP SENSOR COVER C 1 S781WF, S761BF/WF, T791SF
25 A607S4M00AP STEAM SENSOR 1 S781WF, S761BF/WF, T791SF
26 F612E4J50XN INCANDESCENT LAMP (U) 1 AC240V, 25W, 50Hz
27 LJ61424T00AP MICRO SWITCH 1 (V-16G-3C25-L)
28 LJ61414T00AP MICRO SWITCH 1 (D3V-16G-3C25)
31 LJ61784T00AP MICRO SWITCH 1 (SHORT SWITCH) (D3V-1G-2C25)
32 LA606Y4V00GP H.V.INVERTER (U) 1
33 F65854W00AP INVERTER BRACKET A 1
34 L2M261-M32G MAGNETRON 1
35 LA62304210BP FUSE 1 10A/240V, 5Ohz
37 A63264760JP TURNTABLE MOTOR 1
38 LF900C4W00QP AC CORD W/PLUG 1
39 F66624W00AP GROUNDING PLATE 1
40 XTWFNE+12RU SCREW 4 FOR MAGNETRON
41 F90804W00AP CANOE CLIP 1 FOR COVER
42 XTWAFE4+12D SCREW 5 FOR CABINET BODY
43 XTT4+8BFZ SCREW 2 FOR CABINET BODY SIDE (S761BF, S751BF, T791SF)
43 XTT4+8BCR SCREW 2 FOR CABINET BODY SIDE (S781WF, S761WF, S751WF)
44 J692Y4T00QP NOISE FILTER 1

MANUAL 599251
13
45 F0922000EK CUSHION RUBBER 1
46 F0922000BJ CUSHION RUBBER 1
47 F0902000AA CUSHION RUBBER 1 T791SF

MANUAL 599251
14
DOOR ASSEMBLY
Ref
No.
Part Number Part name &
description
Set Remarks
D1 F3018-1200 DOOR KEY A 1
D2 LF30014W00BAP DOOR A 1 S761BF, S751BF
D2 LF30014W00HAP DOOR A 1 S781WF, S761WF,
S751WF
D2 LB301A4W70CP DOOR A (U) UNIT 1 T791SF
D3 LF302K4W00AP DOOR E (U) 1
D4 F30214000AP DOOR KEY SPRING 1
D5 LF30854W00AP DOOR C 1
D6 LF31454W00AP DOOR SCREEN A 1
D7 F31464W00BAP DOOR SCREEN B 1 S761BF, S751BF
D7 F31465W00HQP DOOR SCREEN B 1 S781WF, S761WF,
S751WF
D8 F01729660JP CAUTION LABEL 1
D9 F0902000AP CUSHION RUBBER 1
D10 F0902000AP CUSHION RUBBER 2 T791SF

MANUAL 599251
15
WIRING MATERIALS
Ref
No.
Part Number Part name & description Set Remarks
W1 F030A4W00QP LEAD WIRE HARNESS 1
W2 F030E4W00CP H.V. LEAD WIRE 1

MANUAL 599251
16
ESCUTCHEON BASE ASSEMBLY
Ref
No.
Part Number Part name & description Set Remarks
E1 F603L5B00QP D.P. CIRCUIT 1 S780WF, S760BF/WF
E1 F603L5B10QP D.P. CIRCUIT 1 S750BF/WF
E1 F603L5B20QP D.P. CIRCUIT 1 T790SF
E1 F603L5B50QP D.P. CIRCUIT 1 RTL(W/COMPONENT)
S780WF, S760BF/WF,
S750BF/WF)
E2 F603Y4W00QP D.P. CIRCUIT 1 RTL (W/COMPONENT)
S781WF, S761BF/WF
E2 F603Y4W10QP D.P. CIRCUIT 1 RTL (W/COMPONENT)
S751BF/WF
E3 F630Y5B00HQP MEMBRANE SWITCH
(U)
1 S781WF
E3 F630Y5B10BQP MEMBRANE SWITCH
(U)
1 S761BF
E3 F630Y5B10HQP MEMBRANE SWITCH
(U)
1 S761WF
E3 F630Y5B20BQP MEMBRANE SWITCH
(U)
1 S751BF
E3 F630Y5B20HQP MEMBRANE SWITCH
(U)
1 S751WF
E4 F80344W00BAP ESCUTCHEON BASE 1 S761BF, S751BF
E4 F80344W00HAP ESCUTCHEON BASE 1 S781WF, S761WF, S751WF
E5 F80724W00BAP DOOR OPENING
BUTTON
1 S761BF, S751BF
E5 F80724W00HAP DOOR OPENING
BUTTON
1 S781WF, S761WF, S751WF
E6 F80375950AP COOK BUTTON SPRING 1 S781WF, S761BF/WF,
S751BF/WF
E7 F82564W00AP DOOR OPENING LEVER 1
E8 F66164W20AP FLAT CABLE 1 S781WF, S761BF/WF,

MANUAL 599251
17
S751BF/WF
E9 F00075B00HQP NAME PLATE 1 S781WF
E9 F00075B10BQP NAME PLATE 1 S761BF
E9 F00075B10HQP NAME PLATE 1 S761WF
E9 F00075B20BQP NAME PLATE 1 S751BF
E9 F00075B20HQP NAME PLATE 1 S751WF
E9 F00075B50SQP NAME PLATE 1 T791SF
E10 B890L5B50SQP CONTROL PANEL (AU) 1 T791SF

MANUAL 599251
18
PACKING AND ACCESSORIES
Ref.
No.
Part No. Part name & Description Pcs/s
et
Remarks
P1 F00035B00QP INSTRUCTION MANUAL 1
P2 F01025B00HQP PACKING CASE,PAPER 1 S781WF
P2 F01025B10BQP PACKING CASE,PAPER 1 S761BF
P2 F01025B10HQP PACKING CASE,PAPER 1 S761WF
P2 F01025B20BQP PACKING CASE,PAPER 1 S751BF
P2 F01025B20HQP PACKING CASE,PAPER 1 S751WF
P2 F01025B5SQP PACKING CASE,PAPER 1 T791SF
P3 F01044W00AP UPPER FILLER 1
P4 F01054W00AP LOWER FILLER 1
P5 F01064W00AP P.E.BAG 1
P6 F01074W00AP DOOR SHEET 1
P7 B06014A00AP COOKING TRAY 1
P8 F01084W00AP TRAY PACKING 1
P12 F01924T00AP SHEET 1 S761BF, S751BF, T791SF

MANUAL 599251
19
INVERTER BOARD PARTS LIST
Ref. No. Part No. Part name & Description Pcs /
set
Remarks
C701 ECWF5104N300 CAPACITOR 1 0.1µF, 500VDC
C702 ECQE2405T847 POLYESTER
CAPACITOR
14µF, 250VDC
C703 ECWF5454N300 FILM CAPACITOR 1 0.45µF, 500VDC
C704, C705 ECWH30822JUA FILM CAPACITOR 2 8200PF, 3KVDC
CN701 AEEMXH00703W
G
CONNECTOR 1
CT701 A66904T00AP TRANSFORMER 1
D701, D702 LA6202-4N10T DIODE SI 2 0.3A
D703 AEDNERA3806 DIODE SI 1 0.5A
D704, D705 AEDNERA1506 DIODE SI 2 1A
D706 MA196-(TA5) DIODE SI 1 MA196, 0.1A
DB701 AESTRBV6206 DIODE SI 1 15A, 600V
XTW3+12B SCREW 2 3*12 (FOR Q701)
H.S. A66914T00AP HEAT SINK 1
IC702, IC703 AEICP25011HL IC 2 PS2501-1, HL4P
IC801 AN9DB07SB IC 1
L701 A50204T00AP COIL 1
Q701 A691E4V00GPS TRANSISTOR SI 1 AESCGT60M303
Q702 A691E4V00GPS TRANSISTOR SI 1 AESPGT30J322
XTN3+12B SCREW 1 3*12 (FOR Q702)
Q703, Q704 2SC3311AQSTA TRANSISTOR SI 2 2SC3311AQRS
Q705 2SA1309AQSTA TRANSISTOR SI 1 2SA1309AQRS
R715 AERGS215J452 RESISTOR 1 4.5 K ohms, 15W
VR701 AEVTZ6TLT102 VARIABLE RESISTOR 1 1 K ohm, 308
ZD701,
ZD703,
ZD704, ZD705
AEDZ10ES2T1 ZENNER DIODE SI 4 RD10ES2T1
ZD702 AESZ12JS2T1 ZENNER DIODE SI 1 RD12JS2
T701 A609A4V00GP TRANSFORMER 1

MANUAL 599251
20
DIGITAL PROGRAMMER CIRCUIT (NN-S781, NN-S761) SCHEMATIC DIAGRAM