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1. Replacement of the magnetron
CAUTION
Servicemen should remove their watches whenever
working close to or replacing the magnetron.
Removal of Positive Lock connector
The positive lock connector is a specially designed loose free connector
and you will find this connector in many lead wire connections. To re-
move this connector, pull the lead wire by pressing an extruded lever in
the center of receptacle terminal as shown in Fig. 20.
(A) Discharge the high voltage capacitor. (See page 23)
(B) Remove 2 screws holding thermal cutout.
(C) Remove 1 screw holding air guide A.
(D) Remove 2 high voltage leads from filament terminals.
(E) Remove 4 nuts holding the magnetron.
NOTE: To prevent microwave leakage, tighten mounting nuts properly
making sure there is no gap between the waveguide and the
magnetron.
CAUTION
When connecting 2 filament lead wires to the mag-
netron terminals, be sure to connect the lead wires in
the correct position. The lead wire of high voltage
transformer should be connected to "F terminal" and
the lead wire from high voltage capacitor should be
connected to "FA terminal". (See Fig. 21)
2. Replacement of the fan motor
(A) Remove the magnetron. (Although the fan motor can be replaced
without removing the magnetron, it will give you better access to the
motor).
(B) Disconnect 2 lead wires from the fan motor terminals.
(C) Using a knife or diagonals, cut off the 3 tiny clips from the fan biade,
and remove the fan blade from the motor shaft.
NOTE: A new fan blade is furnished with each replacement fan motor.
(D) Remove 2 screws holding the fan motor.
3. Replacement of the digital programmer circuit (D.P.C.).
NOTE: Be sure to ground any static electric charge built up in your body,
before handling the D.P.C..
:
(A) Unplug the 3-pin connector (CN5) from the D.P.C..
(NE~9970, NE-9970C only)
Caution when removing connector CNS
This connector is a special type which may be very hard to remove
just by pulling directly outward. Instead it can be removed easily by
simply grasping it by the ends and rocking it side to side while pull-
ing. (See Fig. 22)
(B) Unpiug 7-pin (CN2), 8-pin (CN3) and 5-pin (CN6) connectors from the
D.P.C.. (Fig. 22)
(C) Disconnect all lead wires from the power relay A, B and C. (Fig. 22)
(D) Remove 2 screws holding the escutcheon base. (Fig. 22)
(E) Release CN4 connector's lid of the D.P.C. and pull off the flat cable of
the membrane switch. (Fig. 23)
(F) Remove 2 screws holding the D.P.C.. (Fig. 23)
(G) When removing membrane switch, remove 7 screws holding escutch-
eon
bracket and detach the escutcheon
bracket from escutcheon
base.
4. Replacement of the power relay D (on the mini PCB)
(A) Using solder wick or a desoldering tool, carefully remove all solider
from the terminal pins of power relay D.
NOTE:
Do not use a soidering iron or desoidering too! of more than 30
watts on the mini PCB contacts.
(B) With all the terminal pins cleaned and separated from the mini PCB
contacts, remove the defective power relay and install new power
relay making sure all terminal pins are inserted completely. Resolder
all terminal contacts carefully.
ESCUTCHEON,
BASE
HOW TO OISCONNECT
POSITIVE
LOCK
CONNECTOR
THERMAL
CUTOUT
$-PIN
CONNECTOR
(CN6)
7-PIN
CONNECTOR
CCN2)
ESCUTCHEON
BASE
CN4
CONNECTOR
FLAT
CABLE
OF
MEMBRANE
SWITCH
LOCK ING
CLIP
POSITIVE
LOCK
CONNECTOR
WER
RELAY D
LOW VOLTAGE
TRANSFORMER
DIGITAL
PROGRAMMER
CIRCUIT
ESCUTCHEON
BRACKET
Fig. 23
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