Sharp R-771 OE User Manual

TEST PROCEDURES
PROCEDURE
NUMBER
COMPONENT TEST
F
FAN MOTOR TEST
Check if 240 volts is present between the motor terminals. If voltage is present, but motor does not turn, replace the
fan motor. check for loose or broken wire connections.
G
TIMER TEST
.
TIMER CONTACTS TEST
Advance the timer and then return to
“0” position and check for continuity between the terminals. If an open
circuit is indicated at the advanced position or closed a circuit is indicated at “0” position, replace the timer.
TIMER MOTOR TEST
Disconnect the wire leads from the timer motor, set the cooking mode at “HIGH” and check with voltage (240) to /
1 the timer coil.
If voltage is present, but the timer motor does not turn, replace the timer.
If no power, check for loose or broken wiring.
H
MAGNETRON THERM0 CUT-OUT TEST
A continuity check across the therm0 cut-out terminals should indicate a closed circuit unless the temperature of
the therm0 cut-out reaches approximately 104” C.
The therm0 cut-out resets automatically at approximately 79” C. An open thermo. cutout indicates overheating of
the magnetron assembly. Check for restricted air flow to the magnetron through the opening in the chassis, especially
the cooling duct.
I
i
UPPER LATCH SWITCH TEST
I
The upper latch switch can be checked with an ohmmeter.
Isolate the switch and then connect the meter
leads to the common (COM) and normally open (NO) terminals of ths switch. The meter should indicate an open
circuit with the door opened and a closed circuit with the door closed.
In case improper operation is indicated, make a necessary switch adjustment or replace the defective switch.
See adjustment procedure on page 21.
J
LOWER LATCH SWITCH TEST
Isolate the switch and connect the ohmmeter leads to the common (COM) and normally open (NO) terminals of the
switch. The meter should indicate an open circuit with the door opened and a closed circuit with the door closed.
When the meter leads connected to the common (COM) and normally closed (NC) terminals of the switch, it should
indicate a closed circuit with the door opened and an open circuit with the door closed.
In case improper operation is indicated, make a necessary switch adjustment or replace the defective switch.
See adjustment procedure on page 21.
K
VARI-SWITCH TEST
The vari-switch is activated by the cam lever and cam. When the variable cooking control is set at “HIGH” position,
the cam is placed far away from the cam lever. In this condition, the vari-switch is turned ON by action of the cam
lever. The vari switch can be checked with an ohmmeter.
When the meter leads connected to the common (COM) and normally open (NO) terminals of the switch, it should
indicate a closed circuit with the cam lever depressed and an open circuit with the cam lever released. If improper
operation is indicated, replace the vari-motor assembly.
I
L
VARI-MOTOR TEST
The vari-motor rotates two (2) revolutions per minute.
Check if 240 volts is present between the motor terminals. If voltage is present, but the motor does not turn,
replace the vari-motor assembly. If no voltage is present, check for loose or broken wire connections.
15

Sharp R-771 OE Specifications

General

Brand	Sharp
Model	R-771 OE
Category	Microwave Oven
Language	English