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

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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 DCM750BWH, connector K4 terminals 9 and 10, DCM-750BAH-OS and DCM-750BWHOS, 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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Contents DCM-750BAH DCM-750BAH-OS DCM-750BWH DCM-750BWH-OS Hoshizaki AMERICA, INC Contents Page Specifications Icemaker DCM-750BAHDCM-750BAH-OS Water TEMP. FDCM-750BWH Potable Water WATER-COOLED CondenserDCM-750BWH-OS Potable Water Water Cooled CondenserII. General Information Construction DCM-750BWH-OS Ice Making Unit Sequence of Operation Startup Control Board Control Board Layout DCM-750BAH, DCM-750BWH Control BoardDCM-750BAH-OS, DCM-750BWH-OS Features LED LightsPower Supply Controls and Adjustments Portion ControlControl Board Check Procedure Ice Making ComponentsDispensing Components DCM-750BAH, DCM-750BWH Float Switch Inlet Water Valve DCM-750BWH-OS Wiring Diagrams Wire Color CodeDCM-750BAH-OS, DCM-750BWH-OS Sequence of Electrical Circuit Ice Making DCM-750BWH-OSIce Purge Cycle Orange WHITE/BLACK Pink WHITE/BROWN RED WHITE/BLUE Violet Hour Drain Cycle / Drain Switch Shutdown Low Water Safety High Pressure Switch Sequence of Electrical Circuit Dispensing Continuous DispensePortion Dispense Performance Data 192Approximate IV. Service Diagnosis Diagnostic Procedure Ice Production Check Diagnostic Charts No Ice ProductionProblem Possible Cause Remedy Problem Possible Cause Remedy Low Ice Production Other Dispensing Opti Serve OS Sensors 5a. Ice Dispensing Continuous Mode 5b. Ice Dispensing Portion Mode5c. Water Dispensing Refrigerant Recovery Removal and Replacement of ComponentsService for Refrigerant Lines BrazingEvacuation and Recharge R-404A Removal and Replacement of Compressor Removal and Replacement of Expansion Valve Removal and Replacement of Evaporator Assembly Components Removal and Replacement of Extruding Head Upper Bearing Wear CheckRemoval and Replacement of Auger Removal and Replacement of EvaporatorPage 5b. Lower Housing Removal and Replacement of Gear Motor Page Removal and Replacement of Water-Cooled Condenser Page Adjustment of Water Regulating Valve Water-Cooled Model Only Removal and Replacement of Fan MotorRemoval and Replacement of Inlet or Dispensing Water Valve Removal and Replacement of Drain ValveRemoval and Replacement of Dispensing System Dispensing Auger and AgitatorDispensing or Agitating Motor Page VI. Cleaning and Maintenance Cleaning and Sanitizing InstructionsCleaning Solution Water SystemSanitizing Solution Dispensing ComponentsBin Control Bracket Snap Pin Maintenance Frequency Area TaskPreparing the Icemaker for Long Storage