WARNING: When you apply
power to the unit, be careful
not to touch any of the high
CONTROL CIRCUIT BOARD CHECK LIST
The following problems indicate a defective
control circuit board:
1. The START function fails to operate, but
the high voltage systems, the interlock
switches, the door sensing, and the relay
checks are good.
2. The oven operates okay with a replace-
ment relay installed.
3. Proper temperature measurements can-
not be obtained.
Set the ohmmeter to the R x 1
scale, and check for continuity
between the two relay terminal
pins. Use the following steps.
1.Remove the wire connectors
from the relay terminals.
2.Use a pair of alligator clips,
and clip the ohmmeter leads
to the two terminals of the re-
lay. Make sure that you do not
allow the clips to short to any-
3.Plug the microwave oven into
an AC receptical.
4.Set the power level, as shown
in the chart in the right col-
umn, and check the relay op-
eration for the ten power lev-
els. NOTE: During the operat-
ing time set for each level, the
relay will close (short) for the
time specified in the chart, and
then open for another speci-
fied amount of time. When the
open time elapses, the cycle
begins again until the cooking
time elapses and the oven
4. The buzzer does not sound, or continues
5. Some segments of one or more digits do
6. Wrong figures appear on the display.
7. The digits on the display flicker.
8. Some of the indicators do not light.
9. The clock does not keep the proper time.
not light up, or they continue to light up,
or segments light when they should not.