C. Control Board Check

Before replacing CB that does not show a visible defect and that you suspect is bad, conduct the following CB check. This procedure will help you verify your diagnosis. Before proceeding, check for proper voltage per unit nameplate. Check that the 24VAC 1A fuse, 10.5VAC 0.5A CT fuse are good, and the 115VAC GM external protector is not tripped. When checking high-voltage (115VAC), always choose a neutral (W wire) to establish a good neutral connection. When checking low-voltage (24VAC and 10.5VAC), always choose a neutral (LBU wire) from CT to establish a good neutral connection.

WARNING! LBU wires are used in both high-voltage and low-voltage applications. When checking low-voltage (24VAC and 10.5VAC) confirm that the neutral (LBU wire) being used is the CB K4 connector pin #2 (LBU wire) from the CT. Not the LBU wire used for GM operation (115VAC) or DV (24VAC power supply) operation.

When checking CB DC-voltage (5VDC), use CB K3 connector pin #1 for DC ground (GND). The "POWER" LED remains on unless power supply is interrupted.

IMPORTANT! Icemaker will not start unless the front panel safety switch is engaged.

1)Remove the front panel and control box cover.

2)Turn on the power supply. Move the power switch to the "ON" position.

3)Startup – "POWER" LED on: Move the control switch to the "ICE" position. Engage the safety switch, the "POWER" LED turns on. IMPORTANT! CB "POWER" LED will not come on unless the front panel safety switch is engaged. Diagnosis: If "POWER" LED does not turn on, check for 10.5VAC at CB K4 connector pin #1 (BR wire) to

pin #2 (LBU wire). If 10.5VAC is present, and the "POWER" LED is off, replace CB. If 10.5VAC is not present, see "IV.B.7) Startup."

4)5VDC Output Checks:

There are 6 CB circuits utilizing 5VDC: high-pressure switch, icemaking control circuit, freeze protect circuit, ice dispense switch, dispense mode switch ("CONTINUOUS" or "PORTION"), and the water dispense switch/water dispense sensor (Opti-Serve model only). The high-pressure switch and the icemaking control circuit can prevent CB from starting the icemaking process.

•High-Pressure Switch: CB must have continuity through HPS to start the icemaking process. HPS is a normally closed switch. Before proceeding to CB check, confirm HPS condition. Turn off the power supply, then remove HPS wires and check continuity across HPS. If open, allow to reset. If HPS does not reset, see "IV.B.10) Freeze Cycle."

a)Push Button Model: If HPS closed, check for 5VDC from CB K4 connector pin

#10 (V wire) to CB K3 connector pin #1 (open). If 5VDC is not present and "POWER" LED is on, replace CB. If 5VDC is present, check for 5VDC from CB K4 connector pin #9 (BR wire) to CB K3 connector pin #1 (open). If 5VDC is not present, replace HPS or HPS wiring. If 5VDC is present, HPS circuit is good and WV should energize and start filling the reservoir. If not, see "IV.C.5) Fill Cycle."

b)Opti-Serve Model: If HPS closed, check for 5VDC from CB K4 connector pin #6 (BR wire) to CB K3 connector pin #1 (open). If 5VDC is not present and "POWER" LED is on, replace CB. If 5VDC is present, check for 5VDC from CB K4 connector pin #5 (V wire) to CB K3 connector pin #1 (open). If 5VDC is not present, replace HPS or HPS wiring. If 5VDC is present, HPS circuit is good and WV should energize and start filling the reservoir. If not, see "IV.C.5) Fill Cycle."

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Hoshizaki DCM 300BAH(-OS) service manual Control Board Check, 5VDC Output Checks
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DCM 300BAH(-OS) specifications

The Hoshizaki DCM 300BAH(-OS) is a high-performance ice and water dispenser designed to meet the demands of various commercial environments. Known for its reliability and efficiency, this machine is widely used in restaurants, hotels, and catering services where a continuous supply of ice is essential.

One of the standout features of the DCM 300BAH(-OS) is its ability to produce crescent-shaped ice, which is favored in many settings for its hardness and slow-melting properties. This type of ice helps maintain the temperature of beverages longer without diluting them too quickly, making it ideal for mixed drinks and soft drinks alike.

Technology-wise, the Hoshizaki DCM 300BAH(-OS) integrates advanced refrigeration components that enhance energy efficiency. The machine is designed with a patented cooling system that reduces energy consumption while maintaining optimal ice production. Moreover, it is equipped with a highly efficient compressor that ensures quick recovery times even during peak usage.

One characteristic that sets this model apart is its space-saving design. With a footprint that allows for easy placement in tight quarters, it is particularly suited for establishments with limited counter space. The sleek and contemporary exterior also means it complements a variety of decor styles, making it a versatile addition to any commercial kitchen or bar.

The unit boasts a user-friendly interface, with easy-to-read indicators for ice and water levels, allowing staff to manage operations seamlessly. Additionally, the DCM 300BAH(-OS) features a self-cleaning cycle, which automates the sanitation process to ensure the utmost hygiene standards are maintained. This feature not only saves time but also enhances the longevity of the unit by reducing wear and tear.

Its durable construction is another strong point. Built from high-quality stainless steel, the DCM 300BAH(-OS) is resistant to corrosion and wear, ensuring it can withstand the rigors of daily use. Furthermore, Hoshizaki products are renowned for their reliability, and this model upholds that reputation, providing consistent performance with minimal downtime.

In summary, the Hoshizaki DCM 300BAH(-OS) stands out for its efficient ice production, innovative technology, space-saving design, user-friendly features, and robust durability, making it an ideal choice for any business that requires a reliable ice and water dispensing solution.
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