User Manual

R21LCF
7 – 1
R21LCF
Service Manual
CHAPTER 7. 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 monitor fuse,
check the monitor switch, primary interlock relay (RY1), door sensing
switch and secondary interlock switch before replacing the monitor
fuse. If monitor fuse is replaced, the monitor switch must also be
replaced. Use part FFS-BA033WRKZ as an assembly.
IMPORTANT:
Whenever troubleshooting is performed with the power supply cord
disconnected. It may in, some cases, be necessary to connect the
power supply cord after the outer case has been removed, in this
event,
1) Disconnect the power supply cord, and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Disconnect the leads to the primary of the power transformer.
5) Ensure that the leads remain isolated from other components and
oven chassis by using insulation tape.
6) After that procedure, reconnect the power supply cord.
When the testing is completed,
1) Disconnect the power supply cord, and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Reconnect the leads to the primary of the power transformer.
5) Reinstall the outer case (cabinet).
6) Reconnect the power supply cord after the outer case is installed.
7) Run the oven and check all functions.
[1] TROUBLESHOOTING CHART
Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.
TEST PROCEDUR E
CON DITIO N PROBLEM
POSSIBLE CASE
AND
DE F E CT IV E PAR T S
Home fuse or circuit breaker blows when
powercordis pluggedintowalloutlet.
Monitor fus e blows when power cord is
plugged into wall outlet.
Oven lamp does not light, and fan motor
and antenna motor do not operate.
O ven does not go into cook cycle when
Light Up Dial turned.
O ven s eems to be operating but little or
no heat is produced in oven load. (F ood
incompletely cooked or not cooked at all
at end of cook cycle.)
Oven goes into a cook cycle but
extremely uneven hea ting is produced in
oven load (food).
OFF
CONDITION
C OOKING
CONDITION
MAG N E TR ON POWER TRANSFORMER H .V. R E CTIFIE R AS S E MBL Y HIG H V OL T AG E CAP ACIT O R THE R MAL CUT -OUT SEC O NDAR Y INT E R L OC K S W IT C H PRIMARY INTERLOCK SYSTEM MO NITOR S WITC H MO NITOR FU S E NOIS E FILTE R CONTROL PANEL RELAY (RY2) FOIL PATTURN ON P.W.B. LOW VOLTAGE WR ONG OPE R ATION DIRT Y O V EN CAV IT Y SHORTED IN POWER CORD OVE N LAMP OR S OCKE T COOLING FAN MOTOR ANTE NNA MOTOR
S H O R T O R O P E NE D W IR IN G
ABCDE FFGHI JKL RE RE RE RE RE CK CK CK