Hoshizaki DCM-750BAH-OS Controls and Adjustments Portion Control, Control Board Check Procedure

3. Controls and Adjustments

a)Portion Control

When the dispense mode switch is placed in the "PORTION" position, a variable resistor (located on the control board) controls the ice dispense time.

The figures on the label indicate dispensing time (sec.). When shipped, the portion control is set at the minimum dispensing time (0.6 sec.). DCM-750BAH(-OS), DCM-750BWH(-OS). . . . . . .Approximately 0.72 oz.

Amount of ice dispensed per second.

DCM-750BAH(-OS), DCM-750BWH(-OS) . . . . . . Approximately 1.2 oz.

4. Control Board Check Procedure

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.

a)Power Supply

1.Move the control switch to the "ICE" position. The "POWER" LED should come on. If the "POWER" LED is off, check that the power supply is on, the power switch is in the "ON" position, the door switch is engaged, and the control switch is in the "ICE" position. Check the transformer 10.5V secondary circuit and fuse. If the 10.5V secondary circuit (K4 pins 1 and 2) has proper voltage and the "POWER" LED is off, the control board is bad and should be replaced.

If the secondary circuit does not have proper voltage, see "IV.C.1.[1] The icemaker will not start (Fill Cycle)" for further details.

b)Ice Making Components

1.Confirm the reservoir is full of water. If no water is in the reservoir, make sure that the control switch is not in the "DRAIN" position and that the unit is not in the 12 hour drain cycle. Also check the water supply line, water shutoff valve, and water filters. In the fill cycle, the "POWER" LED is the only LED lit on the control board. If no water is filling the reservoir, check for 24V at connector K2 terminal 7 to neutral and connector K3 (DBU) to neutral. If there is 24V at connector K2 terminal 7 to neutral and no voltage at K3 (DBU) to neutral, the control board is bad and should be replaced. See "IV.C.1.[1] The icemaker will not start (Fill Cycle)" for further details.

2.When the reservoir is full, the "GM" LED comes on and the gear motor starts. If the "GM" LED does not come on or the gear motor does not start, check that the following safety circuits are closed: a) high pressure switch (DCM-750BAH and DCM‑750BWH, connector K4 terminals 9 and 10, DCM-750BAH-OS and DCM-750BWH‑OS, connector K4 terminals 5 and 6), b) low water safety/bin control/ice making switch circuit (connector K4 terminals 3 and 4). Next, check for 115/120V at connector K1 "COM" and K1 "NO" on the control board to neutral. If the "GM" LED is on and there is voltage at K1 "COM" to neutral and no voltage at K1 "NO" to neutral, the control board is

bad and should be replaced. See wiring diagram "III.C.2. Ice Purge Cycle" for further details.

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