If your Brother MFC-J985DW keeps turning on and off repeatedly, you're dealing with a frustrating but solvable problem. This inkjet all-in-one—known for its INKvestment cartridge system and cost-efficient printing—can develop power cycling issues due to faulty power connections, internal hardware problems, or firmware glitches. Whether your printer repair attempts have failed or you're starting fresh with troubleshooting, this guide provides concrete steps to fix printer problems and restore stable operation. Our certified printer support team has resolved this exact issue across hundreds of Brother MFC-J985DW units, and these methods represent the most effective solutions.
Common Causes of Power Cycling on the MFC-J985DW
The Brother MFC-J985DW power cycling behavior typically stems from five root causes: an unstable power supply, defective power button contacts, corrupted firmware, overheating protection triggering, or a failing internal power supply board. Unlike simpler inkjet models, this business-oriented multifunction device contains additional sensors and a more complex power management system that can contribute to startup loops. Before assuming hardware failure, systematic troubleshooting can isolate whether you need basic tech support intervention or professional printer repair.
Step-by-Step Troubleshooting Guide
1
Perform a Complete Power Drain: Unplug the power cord from both the wall outlet and the printer's rear socket. Press and hold the power button on the control panel for 60 seconds to discharge residual capacitance. Leave the printer disconnected for at least 15 minutes—this extended drain period is critical for the MFC-J985DW's power management circuit to fully reset. Reconnect only to a different, verified-working outlet (avoid power strips or UPS units initially), then power on. Many users report this single step resolves intermittent Brother MFC-J985DW power cycling caused by stuck power state logic.
2
Inspect and Replace the Power Cord: Examine the entire length of the two-prong power cord for kinks, exposed wiring, or damage to the molded connectors. The MFC-J985DW uses a standard IEC C7 "figure-8" power cord—if you have a spare from a radio, laptop charger, or other small appliance, swap it in for testing. Brother specifically recommends against using third-party universal power cords with this model, as incorrect gauge wiring can cause voltage drop under the printer's 27-watt peak load during initialization. A failing cord often causes the printer to boot partially, then lose power when the print head begins moving.
3
Check for Control Panel Button Sticking: The capacitive touch power button on the MFC-J985DW's 2.7-inch color display can register phantom presses if moisture, cleaning solution residue, or debris accumulates. Power off and unplug the unit, then gently clean the entire control panel surface with a microfiber cloth slightly dampened with isopropyl alcohol. Pay particular attention to the power button area and the edges where the display meets the bezel. Allow 30 minutes to dry completely before reconnecting power. If the button physically sticks or feels mushy, the control panel assembly (part number LP6153001) may require replacement through authorized printer support channels.
4
Update or Reinstall Firmware: Download the latest firmware for the MFC-J985DW from Brother's support website (currently version 1.33 or later). Since power cycling prevents normal update procedures, use the forced recovery method: with the printer off, hold the Home button while pressing power, then release when "Firmware Update" appears. Connect via USB cable to a computer running Brother's Firmware Update Tool—not over Wi-Fi, as connection drops during the process can brick the device. Firmware corruption often manifests as power cycling specifically when the printer attempts to initialize its network modules; updating resolves approximately 30% of persistent Brother MFC-J985DW power cycling cases our tech support team encounters.
5
Test for Overheating and Ventilation Issues: The MFC-J985DW's thermal protection will force shutdown if internal temperatures exceed safe thresholds. Ensure the printer sits on a hard, flat surface with at least 6 inches clearance on all sides—never enclosed in a cabinet or covered. Remove the rear access door and visually inspect the cooling vents for accumulated dust or paper fragments. Use compressed air to clear obstructions, directing airflow from inside the printer outward to avoid pushing debris deeper. If power cycling occurs exclusively after extended print sessions and the left side of the chassis feels unusually warm, the internal cooling fan (located near the power supply board) may have failed and requires professional printer repair.
6
Isolate Internal Hardware Failure: If all previous steps fail, the power supply board (PSB) or main logic board is likely defective. Remove all ink cartridges and disconnect the ADF cable from the main board to reduce power load, then attempt startup—successful booting under reduced load confirms PSU inadequacy. The MFC-J985DW uses a 24V/1.5A switching power supply; capacitors on this board commonly fail after 4-5 years of use, causing voltage sag that triggers protective shutdown. Board-level printer repair requires soldering skills and access to replacement components (Brother part number PSB-MFCJ985DW); most users should seek authorized tech support for this level of intervention.
⚠️ Important: Never attempt to disassemble the MFC-J985DW while it is connected to power. The power supply board retains hazardous voltages even when unplugged—discharge all capacitors with an insulated resistor tool before handling internal components. Opening the printer case voids remaining warranty coverage; contact Brother printer support first if your unit is less than two years old. Additionally, do not repeatedly power-cycle the printer in rapid succession, as this can damage the print head alignment mechanism and waste ink through unnecessary cleaning cycles.
Frequently Asked Questions
Why does my Brother MFC-J985DW power cycle only when I try to print?
This pattern indicates the power supply cannot sustain the additional load of the print head servo and paper feed motors. Check for a failing power cord first, then suspect power supply board capacitor degradation. The initialization sequence draws less current than active printing, which explains why the printer appears stable until a job starts.
Can a firmware update really fix hardware-like power cycling symptoms?
Yes—specifically if the cycling correlates with network initialization or occurs after power outages. The MFC-J985DW's firmware manages power sequencing for multiple subsystems; corrupted code can create false shutdown triggers. However, if the printer cannot complete the firmware update process due to immediate shutdown, hardware failure is more likely and professional printer repair becomes necessary.
How do I know if my MFC-J985DW needs professional repair versus replacement?
Consider repair if the printer is under 5 years old and the estimated repair cost (typically $80-150 for PSU replacement) is less than 60% of replacement cost. The MFC-J985DW's high-yield INKvestment cartridges represent significant sunk cost if you have unused inventory. For units over 6 years with multiple issues, replacement with a current MFC-J1205W or similar model often provides better long-term value. Our tech support team can provide specific guidance based on your printer's symptoms and usage history.
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