PowerFlex 700 Keeps Restarting? How to Troubleshoot Power Cycling and Startup Failures

You’ve just unpacked a new Allen-Bradley PowerFlex 700 drive. You wire it up, power it on, and suddenly it starts power-cycling. No motor leads connected. Voltage seems fine. The drive won’t stay stable.

Now what?

Before assuming the drive is dead out of the box, take a few critical troubleshooting steps. In this post, we’ll explore why a PowerFlex 700 might keep restarting, what components are likely to be blamed, and how to determine whether it’s fixable or headed back under warranty.

Is It Really Dead? Common Reasons a PowerFlex 700 Keeps Restarting

While rare, PowerFlex 700 drives can exhibit power-cycling behavior immediately after installation. The issue often isn’t with the entire drive — it’s usually tied to one of a few known culprits:

• Faulty HIM (Human Interface Module) – A bad HIM can cause the drive to reset continuously, even with no motor leads connected.
• T-Board or HIM Socket Failure – This interface board connects the HIM and communication modules to the drive. If loose or damaged, it can trigger reboots.
• Control Board Malfunction – Less commonly, a failed main board or capacitor issue may cause power cycling.
• Power Supply Instability or Loose Terminals – Voltage instability or improper wiring can also trip protection circuits.
• Factory Parameter Conflicts – Sometimes default drive settings don’t match the install environment and cause resets on boot.

Fast Troubleshooting Steps (Before Returning the Drive)

Here’s what experienced automation techs recommend when you're dealing with a power-cycling PowerFlex 700:

1. Remove the HIM

Disconnect the Human Interface Module and power the drive again. If the cycling stops, the HIM or its socket is likely at fault.

2. Try a Known-Good HIM

If you have another drive on hand, swap in a HIM you know works. If the issue disappears, the original HIM or T-board may be bad.

3. Use DriveExecutive or CCW Software

Connect to the drive with a 1203-USB or 1203-SSS interface. Use DriveExecutive or Connected Components Workbench to read drive parameters and fault history. If communication is stable, the issue may be isolated to the HIM or side board.

4. Inspect the T-Board and Side Connections

Look for misaligned pins, corrosion, or physical damage around the HIM socket. If you’re lucky, it’s a simple connectivity issue.

5. Confirm Proper Voltage and Terminal Tightness

Double-check your input voltage and ensure all terminals are secure. Loose connections or grounding issues can cause drive resets that look like cycling behavior.

When to Return the Drive

If the drive continues to power cycle after all components are removed and all connections checked, it may be a defective unit. At that point, the best course of action is to initiate the return or RMA process.

Most PowerFlex 700 drives include a warranty when purchased new or through authorized distributors. Be sure to document your testing steps when initiating a return.

Pro Tips to Avoid These Headaches

• Bench Test Before Install – Quickly spot issues by powering up the drive before wiring it into the cabinet.
• Keep a Spare Drive or Two on Hand – Swapping in a known-good drive can instantly rule out wiring or load problems.
• Buy from Verified, Warranty-Backed Suppliers – At Industrial Automation Co., we make sure every drive is tested before it ships — and we back it with a 2-year warranty.

Conclusion: Diagnose Before You Dispose

When a PowerFlex 700 starts power cycling right out of the box, it can feel like a disaster, but it doesn’t always mean the drive is defective. Many issues are related to peripherals like the HIM or T-board. With the right approach, you can quickly determine whether the problem is repairable or warrants a return ticket.