Panasonic NN-T221MB, Service Manual, Page: 11 / 21

11
8 Disassembly and Parts Replacement Procedure
8.1. Magnetron
1. Discharge the high voltage capacitors on the inverter cir-
cuit.
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 guide A.
6. Disconnect the two high voltage leads from the magne-
tron.
7. Remove the four screws holding the magnetron.
NOTE: After replacing the magnetron, tighten the mount-
ing screws making sure that there is no gap between the
waveguide and the magnetron to prevent microwave leak-
age.
Caution
When replacing the magnetron, ensure that the antenna
gasket is in place.
Note
The magnetron used for this model is unique for the inverter
power supply system. Make sure to use the one as listed in
the parts list.
Removal of the magnetron
Figure 1
8.2. Inverter power supply (U)
1. Discharge the high voltage capacitors.
2. Remove two screws holding the tie bar.
3. Unplug the H.V. Lead wires from the magnetron.
4. Remove the one screw holding the earth wire to the mag-
netron.
5. Remove the connector CN701 and 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 by un-clipping the catch hooks.
9. Remove the four screws holding the PCB to the inverter
support base.
Caution when replacing the inverter power supply (U)
1. Make sure that grounding plate is in place.
2. Securely tighten the grounding screw through the side of
the chassis (Base).
3. Securely connect the 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.
Removal of the inverter PCB.
Figure 2
Disconnecting the PCB lock connector.
Figure 3