Panasonic NN-A883WB User manual

MOP0307006C2
MicrowaveOven
NN-A813AB/ NN-A873SB/ NN-A883WB
32 Litre
EPG Europe
SPECIFICATIONS
1995 Matsushita ElectricIndustrial Co., Ltd. All rights reserved.
Unauthorizedcopying and distribution isaviolation oflaw.

1. Inverter Warning
The inverterboardlooks like a regularPCB, however, this PCB drives the magnetron tube using
veryhigh voltages and current.
Ithas
1. Veryhigh voltageand high current
2. AnAluminium heat sinkthat becomes veryhot
3. Thecapacitorson theinvertercircuitwill containahigh voltage
chargeevenwhentheovenisnotoperating.
Donot
1. Donottouchthecircuitryas itcontainsveryhigh voltages. When
replacing theboard please take extremecaretoavoidpossible
electricshock. High voltages mayremaininthecircuit.
2. Donottouchthealuminium heat sinkas itwill becomeveryhot. It
alsocontainshigh voltages.
3. DonotattempttorepairtheinverterPCB as thiscanbevery
dangerous. Replace thehigh voltageinvertercircuitas a
complete unit. Return theoldunitfullyrepackedintheoriginal
shipping boxand completedpaperwork.
4. Donotadjust or tamperwiththepreset volumeon theinverter
board. Itisverydangeroustoadjust thispreset withoutproper
test equipment.
5. Donottest theovenwhiletheinvertergrounding stripor screws
areloose. Itisverydangeroustooperate theinvertercircuitboard
withoutaproperground connection.
Figure 1

InverterGounding
Figure 2
InverterPCB layout
2. Feature Chart
Function A813ABEPG
Microwave 6
Grill 3
Convection 17
Combination YES
Sensorreheat 2
Sensorcook 2
Sensorcombination 4
Weight defrost 3
Weight combination 8
Weight reheat -
Weight cook -
Stage cooking 3
Delay/Stand YES
More/Less YES
Kg->lb/oz YES
Clock 12H
Wordprompt English
StepbyStep LED

3. Control Panel
4. Operation And Digital Programmer CircuitTest
Procdure

5. SchematicDiagram

6. Wiring Diagram
7. Description ofOperation
7.1. Variablecooking powercontrol
The HIGH VOLTAGEINVERTER POWER SUPPLYcontrols the output powerbya signal from
the Digital ProgrammerCircuit(DPC). The PowerRelay(RY1)turns on to supplypowerto the
invertercircuit. The level of output poweris controlledbythe drive signal level from the inverter
circuitas indicatedinthe table below.
/ NOTE1:The ON/OFF time ratiodoes not correspond with the percentage of microwave power
since approximately2 seconds are requiredforheating the magnetron filament.
NOTE2:Ifmicrowave cooking is over8 minutes on HIGH power, the fanmotorrotates for1

minute aftercooking to cool the ovenand its electrical components. /
DutyCycles forMicrowave Cooking
OUTPUT
(watts) DUTYON/OFF (seconds)
ON time OFF time
HIGH 1000 22 0
DEFROST 270 16 6
MEDIUM 600 22 0
LOW 440 22 0
SIMMER 250 15 7
WARM 100 8 14
7.2. Grill Cooking
The Digital ProgrammerCircuitcontrols the grill powerbyoperating the powerrelayRY4 inthe
sequence displayedinthe table below:
/
DutyCycles forGrill Cooking
DUTYON/OFF (seconds)
ON time OFF time
Grill 1 66 0
Grill 2 54 12
Grill 3 42 24
7.3. AutoWeightDefrost and AutoWeightCook
Whenanauto control feature is selectedand the startpadpressed:
1. TheDigital ProgrammerCircuitdetermines thepowerlevel and
thecooking timeand indicates theoperating state inthedisplay.
Thetablebelowshowsthecorresponding cooking times for each
categoryand its respectiveweight.
2. Whenthecooking timeinthedisplaywindowhas elapsed, the
oventurnsoff automaticallyviathecontrol signal from theDigital
ProgrammerCircuit.
Note: Afterauto cooking, ifthe oventemperature is overthe predeterminedtemperature then
the fanmotorwill thenrotate to cool the ovenand its components.
Auto Weight Defrost
CATEGORY 1stTOUCH
WEIGHT
(grams)
COOKINGTIME
Bread& Rolls 100 4m18s
MeatItems 200 3m40s
MeatJoints 400 6m20s

Auto Weight Cook
CATEGORY 1stTOUCH
WEIGHT
(Grams)
COOKINGTIME
ChilledPizza 400 08m20s
FrozenPizza 400 08m40s
ChilledQuiche 400 12m40s
FrozenQuiche 400 12m40s
ChickenPieces 500 14m40s
ChickenWhole 1300 23m55s
Pork / Veal 1200 35m00s
Beef 900 26m00s
Lamb 1200 30m05s
Tarte 6 -8 (pieces) 29m00s
7.4. Convection Cooking
1. TheDigital ProgrammerCircuitoperates thepowerrelaysRY3,
RY5and RY6inthesequence illustratedbelow.
2. Whentheovenreaches apredeterminedtemperaturethedigital
programmercircuitstopssupplying powertotherelayRY5,
resulting intheconvection heaterturning off.
3. Whenthetemperaturedropsbelowthepredetermined
temperature, thedigital programmercircuitsupplies powertothe
relayRY5resulting intheconvection heaterturning on.
Note:Aftertheconvection process, iftheoventemperatureis
higherthanthepredeterminedtemperature, thefanmotor rotates
tocool theelectroniccomponents and thoven.