Sharp R-1900J Service Manual

R1900J
5 – 1
R1900J
ServiceManual

CHAPTER 5. TROUBLESHOOTING GUIDE
When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many of the possible causes of
trouble will require that a specific test be performed. These tests are given a procedure letter which will be found in the “Test Procedure“ section.
IMPORTANT:
If the oven becomes inoperative because of a blown weak point (1) or (2), check the monitor switch (1) or (2), primary interlock relay RY1, door sens-
ing switch and secondary interlock switch (1) or (2), before replacing the weak point (1) or (2).
Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.
Home fuse blows when power cord is plugged into wall receptacle " . " does not appear in display when power cord is first plugged into wall receptacle. Oven lamp does not go on for 1 minute after door is opened. Oven lamp and antenna motors do not go on in cook cycle. Fan motor does not operate. Exhaust fan does not operate. Exhaust motor does not operate.
OFF CONDITION CONDITION
PROBLEM
COOKING CONDITION
POSSIBLE CAUSE AND
DEFECTIVE PARTS
TEST PROCEDURE
MAGNETRON (1), (2)
POWER TRANSFORMER (1), (2)
H.V. RECTIFIER ASSEMBLY (1), (2)
HIGH VOLTAGE CAPACITOR (1), (2)
SECONDARY INTERLOCK SWITCH (1), (2)
PRIMARY INTERLOCK SYSTEM
DOOR SENSING SWITCH
MONITOR SWITCH (1), (2)
WEAK POINT (in Noise filter)
MAGNETRON TEMP. FUSE (1), (2)
OVEN TEMPERATURE FUSE
OVEN LAMP OR SOCKET
FAN MOTORS
EXHAUST FAN
EXHAUST MOTOR
WEAK POINT (1), (2)
WEAK POINTS (for Fan motors)
WEAK POINT
(for Exhaust fan motor)
EXHAUST THERMISTOR
MAGNETRON THERMISTOR
NOISE FILTER
KEY UNITS
POWER UNIT
RELAY UNIT
CONTROL UNIT
SWITCH UNIT.
AIR FLOW BLOCKED
LOOSE WIRING
SHORT IN POWER SUPPLY CORD
NO POWER AT OUTLET
LOW POWER SUPPLY VOLTAGE
ABCDEF FG
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Weak point (in noise filter) blows when pow- er cord is plugged into wall receptacle. Oven doen not go into cook cycle when START pad on the door is touched. Oven does not go into cook cycle when START pad is touched. Variable cooking does not operates proper- ly, except HIGH power functions. Low or no power is produced during cook- ing condition. (The food is heated incom- pletely or not heated at all.)
Oven goes into a cook cycle but shuts down before and off cooking cycle. It seems that the output power is low- er or higher than the rated one.

Sharp R-1900J Specifications

General

Brand	Sharp
Model	R-1900J
Category	Microwave Oven
Language	English