the screen on the parent unit just went black and won't turn back on, but i can hear the charging sound when i plug it in.

Diagnosis

The Motorola Halo Plus MBP944 parent unit utilizes a lithium-ion battery that can enter a "deep discharge" or "frozen" state if the voltage drops below a critical threshold. When this happens, the internal power management IC (Integrated Circuit) may prevent the screen from initializing to protect the battery, even though the charging circuit is active—which is why you still hear the audible charging chime when plugging in the AC adapter. Alternatively, this is often caused by a firmware hang where the processor is stuck in a boot loop or a sleep state from which it cannot wake. Because the screen is the highest power-draw component of the unit, the system will prioritize the charging chime and basic power intake over the LCD backlight. You can confirm this is a software/power hang rather than a hardware failure if the unit feels slightly warm to the touch near the top edge while plugged in, indicating the processor is active but the display is not receiving the signal to wake.

How to Fix It

To resolve a frozen display or a deep discharge state, you must force a hardware-level power cycle to clear the volatile memory and jumpstart the battery charging sequence.

1. Disconnect the parent unit from the charging cable and ensure it is completely unplugged from the wall outlet.
2. Locate the Power button on the top edge of the parent unit. Press and hold this button firmly for a full 60 seconds. Do not let go, even if you see a flicker of light or hear a sound; this drains any residual capacitance from the internal capacitors.
3. Plug the official Motorola AC adapter directly into a wall outlet (avoid using USB hubs or power strips for this step to ensure maximum amperage).
4. Connect the cable to the parent unit. You should hear the charging chime.
5. Leave the unit plugged in and untouched for at least 4 hours. Do not attempt to power it on immediately; the battery needs to reach a minimum voltage threshold before it can support the power draw of the LCD screen.
6. After 4 hours, press and hold the Power button for 3-5 seconds to boot the device.

If That Didn't Work

• Perform a Factory Reset via the Camera: Since the parent unit is unresponsive, try resetting the connection from the source. Power cycle the baby camera unit by unplugging it for 30 seconds. While the camera is rebooting, hold the power button on the parent unit. This can sometimes force a new handshake between the WiFi module and the display.
• Test with a High-Output Power Source: The MBP944 is sensitive to voltage drops. If your original cable is frayed or the adapter is failing, it may provide enough power for the chime but not enough to boot the screen. Try a known-working 5V/2A USB power adapter and a high-quality micro-USB cable to rule out a faulty charger.
• Check for "Screen Off" Mode: It is possible the unit is actually on, but the screen has been timed out or dimmed to the lowest setting. Press the 'OK' or 'Menu' button several times rapidly. If the unit is paired and active, this should trigger the wake-up command for the LCD.
• Battery Terminal Inspection: Inspect the charging port for lint or debris. Use a wooden toothpick or compressed air to clear the port. If the pins are not making full contact, the unit may "ping" to indicate power is present but fail to actually draw the current necessary to charge the battery and power the screen.

Heads Up

• Avoid Deep Discharge: To prevent this from happening again, avoid letting the parent unit battery drop to 0%. Plug it in once it hits 20% to maintain the health of the lithium cells.
• Use Official Cables: Third-party charging cables often lack the correct gauge to provide the steady current required by the Halo Plus, which can lead to "ghost" charging where the chime sounds but the battery doesn't actually fill.
• Temperature Sensitivity: Do not leave the parent unit on a hot windowsill or in direct sunlight. Overheating can trigger a thermal shutdown that disables the screen to protect the internal components.
• Firmware Updates: Once you regain screen access, check the Motorola Nursery app for any available firmware updates for the MBP944 to resolve known stability bugs.