Parts Replacement Procedure - Panasonic NN-E251W Service Manual

6. PARTS REPLACEMENT PROCEDURE

6.1 Magnetron
1. Discharge the high voltage capacitor.
2. Disconnect 2 high voltage lead wires from the magnetron
filament terminals.
3. Remove 1 screw holding the magnetron.
NOTE: After replacement of the magnetron, tighten
mounting screws properly making sure trhere is
no gap between the waveguide and the mag-
netron to prevent microwave leakage.
CAUTION
When replacing the magnetron, be sure the antenna gas-
ket is in place.
6.2 Digital Programmer Circuit (DPC) and mem-
brane keyboard
NOTE: Be sure to ground any static electric charge built
up on your body before handling the DPC.
1. Disconnect all electrical connectors to the DPC.
2. Remove 2 screws holding escutcheon base and mem-
brane earth tail to oven chassis and slide the escutcheon
base upward slightly.
3. Release CN2 connector's lock of the DPC by pushing
both levers from inside and pull them upward, the remove
the flat cable of the membrane keyboard.
4. Remove 3 screws holding the DPC.
To replace membrane switch keyboard
1. Push the upper part of the keyboard (display window por-
tion) from the back of the escutcheon base and peel off
the membrane keyboard completely from the escutcheon
base.
NOTE 1: The membrane keyboard is attached to the
escutcheon base with double sided adhesive
tape.
Therefore, applying hot air e.g. using a hair dryer
is recommended for smoother removal.
NOTE 2: When installing new membrane keyboard,
make sure that the surface of the escutcheon
base is cleaned sufficiently so that any problems
(shorted contacts or uneven surface) can be
avoided.
NOTE 3: Alignment position of membrane keyboard and
escutcheon sheet are as follows:
Membrane keyboard: Right and lower edges,
Escutcheon sheet: Right and lower adges.
6.3 Low voltage transformer and/or power
relays
NOTE: Be sure to ground any static electric charge built
up on your body before handling the DPC.
1. Using solder wick or a desoldering tool and 30W solder-
ing iron, carefully remove all solder from the terminal pins
of the low voltage transformer and/or power relays.
NOTE: Do not use a soldering iron or desoldering tool
of more than 30 watts on DPC contacts.
2. With all the terminal pins cleaned and separated from
DPC contacts, remove the defective transformer/power
relays and install new transformer/power relays making
sure all terminal pins are inserted completely. Resolder
all terminal contacts carefully.
6.4 Oven thermostat
1. Disconnect 2 lead wires from thermal cut-out
2. Draw froward the oven thermostat
8
MAGNETRON
SCREW