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NE-972
|
TROUBLESHOOTING
GUIDE
CAUTION
. Check grounding before checking for trouble.
. Be careful of the high voltage circuit.
. Discharge high voltage capacitor. (See page 18.)
. When checking the continuity of the switches or the high voltage transformer, disconnect one lead wire from these
parts and then check continuity with the AC plug removed. To do otherwise may result in a false reading or dam-
age to your meter.
5. Do not touch any parts of the circuitry on the digital programmer circuit since static electric discharge may dam-
age this control panel.
Always touch yourself to ground while working on this panel to discharge any static charge in your body.
6. When disconnecting a plastic connector from a terminal, you must hold the plastic connector instead of the lead
wire and then disconnect it, otherwise lead wire may be open or the connector cannot be removed.
7. A 240V AC is present at the shaded area [777 of the digital programmer circuit (Terminals of power relays 2, 3, 5,
6, 7 and Triac etc.).
When troubleshooting, be cautious of possible electrical shock hazard.
hOND
—
A. In case of following conditions, D.P.C. is defective.
1. Incomplete segments.
(A) Segments missing.
(B) Partial segments missing.
(C) Digit flickering other than normal fluorescent slight flickering.
(D) Colon does not turn on or does not blink when the clock pad is
tapped.
A distinct change in the brightness of one or more numbers in the
display.
One or more digits in the display not on when they shouid be.
Wrong or no power indicator light for power level! selected.
. Specific numbers (for example 2 or 3) will not display.
. Display does not count down with time cooking or when using dis-
play as a timer.
. Display does not count up with clock operation.
. Oven is programmable and cooks normally but no display shows.
for NE-972) also.
9. Display obviously jumps in time while counting down or up.
10. Display counts down noticeably too fast while cooking.
1. Display cannot shift from the first stage cooking to the second
stage cooking even though Two Stage Cooking is programmed.
12. Display does not stop counting down with time cooking even
when Stop/Cancel Pad is tapped.
13. Time of day does not reappear when cooking is finished.
ON
MMAW
Fig. 27
B. In case of following conditions, either D.P.C. or membrane switch is defective
CHECK
RESULT
CAUSE
REMEDY
1. Clock set cannot be programmed at all.
eins
2. Some inputs cannot be programmed.
Check continuity of membrane
Some pads have no continuity
switch (Refer to page 23 for
Check continuity of membrane
switch with clock pad tapped.
For NE-972---between termin-
als 6 and 4
For NE-992/993:--between
terminals 6 and 9
the test procedures of mem-
brane switch)
3. Display indicates a number or figure different from one touched.
Random programming when pressing other than touch pads or without pressing any at all. (intermittently)
Everythings works as speci-
fied
Replace membrane switch
and recheck
Still have trouble
Defective DPC
rena
a
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