Whirlpool WRX735SDHZ Refrigerator: Display Flickering... | appliancefaults.com

Technical Background:

The main control unit (MCU) manages all refrigerator functions, including the display and ice maker. The ice maker draws significant current during its cycle. A voltage drop due to a weak power supply or loose connections can cause the display to flicker. The MCU relies on stable 5V DC and 12V DC power, derived from the 120V AC input via the power supply section of the main control board.

Symptoms:

The homeowner observes that the refrigerator's display screen flickers intermittently, specifically when the ice maker is cycling or actively producing ice. This may be accompanied by dimming of the display or other minor anomalies.

Possible Causes:

Low voltage to the MCU during ice maker operation.
Loose wiring connections affecting voltage stability.
Failing capacitor on the main control board (MCU).
Faulty ice maker module drawing excessive current.
Weak or failing power supply within the refrigerator.

Solution:

1

Disconnect power to the refrigerator at the breaker panel.
2

Locate the main control board (MCU) – usually behind the access panel at the top rear of the refrigerator.
3

Visually inspect the board for any signs of burnt components or bulging capacitors.
4

Using a multimeter, check the voltage at the power input to the MCU. It should be approximately 120V AC. Check for voltage drop when the ice maker cycles.
5

Disconnect the ice maker power connector. Reconnect power to the refrigerator and observe if the display flickering stops.
6

If the flickering stops with the ice maker disconnected, replace the ice maker module.
7

If the flickering persists, replace the main control board (MCU).

Safety Warning:

Always disconnect power to the refrigerator at the breaker panel before performing any repairs. Lock Out/Tag Out (LOTO) procedures must be followed. High voltage is present within the refrigerator's components.

Prevention:

Regularly inspect and clean the refrigerator's condenser coils to ensure proper cooling and prevent the power supply from overworking. Ensure the refrigerator is plugged into a dedicated 15-amp circuit.

Expert Tip:

Enter service mode by pressing and holding the door switch and then pressing the 'Freezer Up' and 'Freezer Down' buttons simultaneously. This will allow you to run diagnostic tests on the ice maker and monitor voltage readings during operation.

Frequently Asked Questions

•What is the part number for the main control board (MCU) on the Whirlpool WRX735SDHZ?

The part number varies depending on the manufacturing date, but typically it is W11087100 or a superseded version. Always verify with the appliance's service manual or Whirlpool's parts website using the model number.

•How do I test the ice maker module to confirm it's drawing excessive current?

Using an amp clamp meter, measure the current draw on the ice maker's power wire during its harvest cycle. Compare the reading to the specifications listed in the service manual. Significantly higher current indicates a faulty module.

•What is the acceptable voltage range for the 120V AC input to the main control board?

The acceptable range is typically 110V AC to 127V AC. A voltage significantly below 110V AC can indicate a problem with the household electrical supply.

Whirlpool WRX735SDHZ Refrigerator: Display Flickering During Ice Maker Cycle

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the part number for the main control board (MCU) on the Whirlpool WRX735SDHZ?

•How do I test the ice maker module to confirm it's drawing excessive current?

•What is the acceptable voltage range for the 120V AC input to the main control board?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: