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36
B. Control Board Check
Before replacing a control board that does not show a visible defect and that you suspect
is bad, always conduct the following check procedure. This procedure will help you verify
your diagnosis.
Alarm Reset: If the control board is in alarm (beeping), press the "ALARM RESET"
button on the control board with power on. Once reset, the unit starts at
the 1-minute fill cycle. For audible alarm information, see "II.C.2.f) LED
Lights and Audible Alarm Safeties."
1) Check the dip switch settings to assure that S1 dip switch 3, 4, 7, 8, 9, & 10 and S2 dip
switch 1 through 6 are in the factory default position. S1 dip switch 1, 2, 5, & 6 are
cleaning adjustments and the settings are flexible. For factory default settings, see "II.
C.3.a) Default Dip Switch Settings."
2) Move the control switch to the "ICE" position. If the "POWER OK" LED is on (or flashing
if the bin is full), the control voltage is good. If the "POWER OK" LED is off, check the
control transformer secondary circuit. Transformer output is 10.5V at 115V primary
input. If the secondary circuit has proper voltage and the "POWER OK" LED is off, the
control board is bad and should be replaced. See "V.N. Removal and Replacement of
Control Board."
If the secondary circuit does not have proper voltage, check the control transformer
primary circuit. Check the control switch wire (pink) on the diagnostic connector
to a white neutral wire for 115V. For location of the control switch wire, see "III.
B.2. Diagnostic Connector." Always choose a white neutral wire to establish a good
neutral connection when checking voltages. For additional checks, see "IV.F.1.[1] The
icemaker will not start."
3) The "OUTPUT TEST" button provides a relay sequence test. Move the control switch
to the "OFF" position. While pressing the "OUTPUT TEST" button, move the control
switch back to the "ICE" position. The correct LED lighting sequence is 5, 6, 7, 8,
9, 4. Note that the order of the LEDs from the outer edge of the board is 5, 6, 8, 9,
4, 7. Components (e.g., compressor) cycle during the test. Each LED stays on for
5 seconds. LED 5 stays on while LED 6 is on. The "POWER OK" LED flashes once
when the first relay LED turns on, twice when the second relay LED turns on, and adds
one flash for each LED thereafter. A beep also sounds as each LED turns on. Following
the test, the icemaker resumes operation. If the LEDs do not light as described above,
the control board is bad and should be replaced. See "V.N. Removal and Replacement
of Control Board."
4) Utilize the diagnostic connector to verify voltage output from the control board to the
components. For diagnostic connector details, see "III.B.2. Diagnostic Connector."
With the unit in the cycle to be tested, check output voltage from the corresponding
terminal on the diagnostic connector to ground. If output voltage is not found and the
appropriate LED is on, the control board is bad and should be replaced. See "V.N.
Removal and Replacement of Control Board."