Chapter 5. Troubleshooting Guide - Sharp R-1900J Service Manual

R1900J
CHAPTER 5.
R1900J
TROUBLESHOOTING GUIDE
Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.
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).
VOLTAGE
CORD SUPPLY
THERMISTOR
motor) fan
motors)
FUSE
(2) (1), FUSE
filter)
(2)
SYSTEM
(2) (1), SWITCH
(2) (1), CAPACITOR
(2) (1), ASSEMBLY
(2) (1),
SUPPLY POWER LOW
OUTLET AT POWER NO
POWER IN SHORT
WIRING LOOSE
BLOCKED FLOW AIR
UNIT. SWITCH
UNIT CONTROL
UNIT RELAY
UNIT POWER
UNITS KEY
FILTER NOISE
MAGNETRON
THERMISTOR EXHAUST
Exhaust (for POINT WEAK
Fan (for POINTS WEAK
(2) (1), POINT WEAK
MOTOR EXHAUST
FAN EXHAUST
MOTORS FAN
SOCKET OR LAMP OVEN
TEMPERATURE OVEN
TEMP. MAGNETRON
Noise (in POINT WEAK
(1), SWITCH MONITOR
SWITCH SENSING DOOR
INTERLOCK PRIMARY
INTERLOCK SECONDARY
VOLTAGE HIGH
RECTIFIER H.V.
TRANSFORMER POWER
(2) (1), MAGNETRON
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