Service manual

33
Condition
Display does not
show program-
ming at all, even if
button key is
pressed
Normal
Abnormal
Malfunction of
touch control
circuitry of control
box sub-assembly
Replace control
box sub-
assembly
Check each button for
continuity of the tact
switch keyboard as the
following keyboard check
procedure.
Malfunction of
touch control
circuitry of control
box main-assembly
Replace
control box
main
assembly
Check Result Cause Remedy
32
Condition
Turn table motor,
fan motor and
oven lamp do not
turn on
No
Continuity
No
Continuity
0V
Approx.
-16 VDC
Check continuity of
primary interlock switch
Check continuity of
secondary interlock and
D.O.M. switch
Check D.C. voltage being
supplied to RELAY (RY2)
coil.
Malfunction of
primary interlock
switch
Malfunction of
secondary
interlock and
D.O.M. switch
Defective touch
control circuit
Faulty contacts of
RELAY (RY2) or
open relay coil
ReplaceReplace
Replace
Adjust or
replace
Adjust or
replace
Check Result Cause Remedy
(TROUBLE 4) Display shows all figures selected, but oven does not start cooking, even
(TROUBLE 5) The following visual conditions indicate a probable defective touch control
circuit.
1. Incomplete segments.
(A) Segments missing.
(B) Partial segments missing.
(C) Digit flickering other than normal fluorescent
slight flickering.
(D) “0:00” does not display when power is on.
2. A distinct change in the brightness of one or more
numbers is in the display.
3. One or more digits in the display are not on when
they should be.
4. Display indicates a number different from one
setted.(For example, when 5 setted, 3 appears in
the display.)
5. Specific numbers (for example 2 or 3) do not
display when the dial knob is rotated.
6. Display does not count down or up with time
cooking or clock operation.
7. oven is programmable and cooks normally but no
display shows.
8. Display obviously jumps in time while counting
down.
9. Display counts down noticeably too fast while
cooking.
10.Display can not shift from the first stage cooking to
the third stage cooking while 3 phase cooking
(including defrost).
11. Display does not show the time of day when clear
button is pressed.
12.Oven lamp, fan motor and turn table motor do not
stop although cooking is finished. Check if the
RELAY (RY2) contacts close if they are close,
replace touch control circuit.
M/W Combi Weight
Defrost
TimeGrill
Lock Watt gAuto
Cook
NOTE : Before following the particular steps listed above in the trouble shooting guide for failure, please check for
the continuity of each wire-harness between the tact switch keyboard and PCB assembly.
KEYBOARD CHECK PROCEDURE
1. Type of encoding and key names
The tact switch keyboard consists of 7 keys whose configurations are described above.
2. Key check procedure
To determine if the tact switch keyboard is defective or not, check the continuity of each button contacts with a
multimeter.
1) AUTO COOK button : Between 14 and 13 5) DEFROST/POWER button : Between 14 and 12
2) GRILL/COMBI button : Between 15 and 13 6) STOP/CLEAR button : Between 8 and 12
3) START button : Between 8 and 13 7) CLOCK/LESS button : Between 10 and 12
4) MORE button : Between 10 and 13
14
13
12
15 8 10
AUTO
COOK
DEFROST/
POWER
STOP/
CLEAR
CLOCK/
LESS
GRILL/
COMBI
START MORE
CN101
FIG. 14 KEY MATRIX