Inverter NN-T551CB Service Manual Download Page 2

Page: 2 / 63

1. Inverter Warning

The inverter board looks like a normal printed circuit board. However, this printed
circuit board supplies the magnetron tube with very high voltage and current.
The inverter PCB:

1. Produces very high voltage and current.

2. Has an Aluminium heat sink which becomes very hot.

3. Has capacitors in the circuitry that hold a high voltage charge even when the oven

is not operating.

Do not

1. Do not touch the high voltage circuitry. When replacing the board take extreme

care to avoid possible electric shock.

Summary of Contents for NN-T551CB

Page 1: ...MOP01060022C2 Microwave Oven NN T591WB NN T571SB NN T551WB NN T551CB 27L United Kingdom...

Page 2: ...h voltage and current The inverter PCB 1 Produces very high voltage and current 2 Has an Aluminium heat sink which becomes very hot 3 Has capacitors in the circuitry that hold a high voltage charge ev...

Page 3: ...ircuit as a complete unit 4 Do not adjust or tamper with the pre set volume on the inverter board It is very dangerous to adjust this pre set without proper test equipment 5 Do not operate the microwa...

Page 4: ...BNN T571SB Microwave 4 5 Sensor reheat 2 Sensor Cook 14 Turbo reheat 1 1 Weight reheat 4 Weight cook 4 Weight combination Weight defrost 3 3 Delay Stand Yes Yes More Less Yes Kg lb oz Yes Yes Stage co...

Page 5: ...4 Operation And Digital Programmer Test Procedure 4 1 Setting The Clock 1 Plug the power supply cord into the wall outlet 2 Press the clock pad 3 Enter the time of the day...

Page 6: ...Place a water load in the oven 2 Press Micro power once to set high power 3 Set time at 10 sec by pressing 10 sec pad once 4 Press Micro power pad 3 times to set medium power 5 Set pad for 1 minute by...

Page 7: ...cond stage cooking has elapsed oven bleeps 5 times and shuts off 4 3 Turbo Reheat 1 Place water load in the oven 2 Press the Turbo reheat button once 3 Set time to 1 minute by pressing1 min pad once 4...

Page 8: ...3 Enter the weight by pressing the Up Down or more less pads 4 Press Start 4 5 Delay Stand 1 Set power level and time 2 Press Stand 3 Set standing time 4 Press Start 4 6 Delay Start...

Page 9: ...4 7 Auto Weight Cook Programs NN T551 1 Select the desired auto weight cook program 2 Press to select grams or pounds and ounces 3 Enter the weight by pressing the up and down pads 4 Press Start 4 8 A...

Page 10: ...ck by pressing the start pad three times 5 Schematic And Wiring Diagram 6 Description Of The Operating Sequence 6 1 Variable power cooking control The output power is controlled by the inverter power...

Page 11: ......

Page 12: ......

Page 13: ...ndicates the operating state in the display The table shows the corresponding cooking times for each category and its respective weight 2 When the cooking time in the display window has elapsed the ov...

Page 14: ...es Explanation of the auto sensor cooking process 1 The shaded columns in figure 1 indicate when the humidity sensor heater is on 2 During this 30 second period there is no microwave activity When cal...

Page 15: ...utions to Be Observed When Troubleshooting Unlike many other appliances the microwave oven is a high voltage high current device Though it is free from danger in ordinary use extreme care should be ta...

Page 16: ...sformer however the current is extremely large and is therefore dangerous due to this high current and high voltage The aluminium heat sink is also energized with high voltage HOT so do not touch when...

Page 17: ...0 seconds after the oven is turned off an electric charge remains in the high voltage capacitors in the inverter power supply circuit board When replacing or checking parts remove the power plug from...

Page 18: ...ar these circuits with the oven energized DO NOT measure the voltage in the high voltage circuit including the filament voltage of the magnetron WARNING Never touch any circuit wiring with your hand n...

Page 19: ...he cavity or any holes or gaps because such objects may work as an antenna and cause microwave leakage 7 6 Confirm after repair 1 After repair or replacement of parts make sure that the screws of the...

Page 20: ...n the inverter circuit 2 Remove the screw holding the air guide 3 Remove the two screws holding the tie bar 4 Remove the oven lamp and lead wire harness cables form the air guide A 5 Remove the air gu...

Page 21: ...nd CN702 from the inverter PCB 6 Remove the two screws holding the inverter base to the chassis See figure 2 7 Carefully remove the inverter PCB and support base from the oven 8 Remove the air guide E...

Page 22: ...he 3 lead wire connectors 4 Make sure that the heat sink has enough space gap from the oven Take care not to touch any lead wire to the aluminium heat sink because it is hot Figure 2 Removal of the in...

Page 23: ...base by freeing the 4 catch hooks on the escutcheon base 2 Peel away the display window from the inside of the base 3 Remove the membrane assembly by pushing from the inside of the base and then peel...

Page 24: ...Removal of DPC AU and DPC DU Figure 6...

Page 25: ...ower relays RY1 Note Be sure to ground your body to discharge any static before handling the DPC 1 Using a solder wick or a de soldering tool and a 30W soldering iron carefully remove all solder from...

Page 26: ...n 30 watts on DPC contacts 8 5 Fan Motor 1 Remove two screws and remove the tie bar 2 Disconnect the two lead wires from the fan motor terminals 3 Disconnect all lead wires from the noise filter 4 Rem...

Page 27: ...or A catch hooks Care must be taken not to damage these hooks during disassembly 4 Remove the door key and spring from the door E After replacement of the defective component parts of the door reassem...

Page 28: ...the inner door surface and the oven front surface If the door assembly is not mounted properly microwave power may leak from the clearance between the door and oven 3 Perform the microwave leakage te...

Page 29: ...2 Disconnect the two lead wires connected to the turntable motor 3 Remove the turntable motor by removing the two screws Note After breaking off the motor cover make sure that cut off portions are pro...

Page 30: ...Removing the turntable motor cover Figure 10...

Page 31: ...connector for the digital programmer circuit board 3 Remove the exhaust guide from the steam sensor unit 4 Remove the catch hooks on the sensor mounting plate and air guide 5 Remove the steam sensor...

Page 32: ...Removing the steam sensor...

Page 33: ...e this high voltage 3 Before touching any oven components or wiring always unplug the oven from its power source and discharge the high voltage capacitors 9 1 Primary Latch Switch Secondary Latch Swit...

Page 34: ...2 Connect the test probes of the ohm meter to these leads 3 Test the continuity of the short switch with the door open and the door closed using the lowest ohm scale Door Open Door Closed Monitor swit...

Page 35: ...n the switch terminals by tapping an appropriate pad on the keyboard The keypad matrix is shown on P 28 9 5 Inverter Power Supply Caution DO NOT try to repair this inverter power supply Replace as a w...

Page 36: ...h 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...

Page 37: ...witch 1 When mounting the primary latch switch secondary latch switch and short switch to the door hook assembly Follow the instructions in figure 1 NOTE No specific adjustment during the insulation o...

Page 38: ...heating time as accurate as possible 1 Fill the beaker with exactly one liter of tap water Stir the water using the thermometer and record the waters temperature Record as T1 2 Place the beaker on the...

Page 39: ...0W 8 C 11 Troubleshooting guide Caution 1 Do not try to repair this H V Inverter power supply Replace as a whole unit When returning the inverter unit pack in the original inverter box 2 Do not adjust...

Page 40: ...d wire may become open circuit 7 Do not touch any parts of the circuitry on the digital programmer cicruit since static electric discharge may damage this control panel Whilst working on this board en...

Page 41: ......

Page 42: ......

Page 43: ......

Page 44: ......

Page 45: ......

Page 46: ...0C6430BP POWER SUPPLY CORD 1 2 E607X4L00BP NOISE FILTER 1 3 E67597550GP CERAMIC FUSE 10A 1 4 E030A5D20BP LEADWIRE HARNESS 1 5 E41444N30BP UPPER ORIFICE 1 6 E30208000BP DOOR HOOK 1 7 E6142 1450 PRIMARY...

Page 47: ......

Page 48: ......

Page 49: ...71SB 37 E607S7050AP STEAM SENSOR 1 NN T591WB NN T571SB 38 E407F8010BP STEAM SENSOR ASSY 1 NN T591WB NN T571SB 39 E00064080BP WARNING LABEL 1 40 E40244N30BP EXHAUST GUIDE 1 41 E09250000BD CUSHION RUBBE...

Page 50: ......

Page 51: ......

Page 52: ...1 NN T551WB NN T551CB E7 E66164L00GS RIBBON CABLE 1 E8 E82564L10BP DOOR OPENING LEVER 1 NN T591WB NN T551WB NN T551CB E8 E82564V00SBP DOOR OPENING LEVER 1 NN T571SB E9 E603Y5D30BP DPC DU 1 NN T591WB...

Page 53: ......

Page 54: ......

Page 55: ...E01025D20BP CARTON BOX 1 NN T551CB P8 E01054N30BP LOWER FILLER 1 P9 E01064N70GS VINYL BAG 1 P10 E01076700BP DOOR SHEET 1 P11 E01926430GP PROTECTOR SHEET 1 P12 E01044N30BP UPPER FILLER 1 18 Trim Kit Ac...

Page 56: ......

Page 57: ......

Page 58: ......

Page 59: ......

Page 60: ...AERJ3GSYJ102 1K Chip Resistor 5 R481 AERJ3GSYJ102 1K Chip Resistor 1 R340 AERJ3GSYJ103 10K Chip Resistor 1 R650 AERJ3GSYJ104 100K Chip Resistor 1 R480 AERJ3GSYJ104 100K Chip Resistor 1 R110 AERJ3GSYJ...

Page 61: ...1 8K Resistor 1 Q10 2SD1859TV2 Transistor 1 Q226 AESAKTA200Y PNP Transistor 1 Q222 AESCKTC3199GR NPN Transistor 2 C10 EEUFC1C471B 470uF 16 V Elect Capa 1 C12 ECEA1CKA100B 10uF 16V Electrolytic Capacit...

Page 62: ...ERDS2TJ622T 6 2K Carbon Resistor 1 21 4 E603Y5D30BP DPC DU Ref No Part No Part Name Description Qty Remarks ZD10 AESZMTZ5R6B Zener Diode 1 D223 AESS133T 77 Silicon Diode 2 D25 AESS133T 77 Silicon Diod...

Page 63: ...BP 3 Wire Inverter Connection 1 IC25 AEICP25011HL Photocoupler IC 1 D26 AESTS1WBA60B Diode Bridge 600V 1 C25 ECA2WHG220E 22uF 450V Electrolytic Capacitor 1 BZ310 EFBAH20C001 2KHz Buzzer 1 D1 ERZV10D51...

Search results

Summary of Contents for NN-T551CB

Reviews:

Related manuals for NN-T551CB

Brands by name

Popular brands

Inverter NN-T551CB, Service Manual

Search results

Summary of Contents for NN-T551CB

Reviews:

Related manuals for NN-T551CB

Brands by name

Popular brands