Troubleshooting Low Voltage on Firefighting Monitors: How to Identify the Problem and Fix It with PurePWR

When it comes to electronic firefighting monitors, low voltage can be a hidden troublemaker. It doesn’t always show up right away and can cause problems that are hard to pin down—loss of monitor control, erratic movement, or full failure under heavy load. This guide walks you through how to test for low voltage and introduces TFT’s PurePWR, a plug-and-play solution to help stabilize power and prevent monitor issues in the field.

What Are the Symptoms of Low Voltage?

The first sign you might be dealing with low voltage is the flashing power indicator light on the front of your monitor. A slow blink usually means the system isn’t getting enough power, especially during peak current draw, such as when the monitor moves to a hard stop.

Tools You’ll Need

To diagnose the problem, gather the following:

  • Multimeter (must capture both max and min voltage readings)
  • 3mm Allen wrench
  • Basic mechanical tools to open the monitor housing

Step-by-Step: How to Check for Low Voltage

  1. Power Down First
    Always disconnect power before opening the monitor enclosure.
  2. Access the Monitor Internals
    • Remove the four bolts using your 3mm Allen wrench.
    • Gently lift the cover while watching for the ribbon cable inside.
    • If the ribbon cable disconnects, simply pivot the locking tabs, reconnect it, and lock it back into place.
  3. Partially Reassemble for Testing
    Reattach the right two bolts to the left-side holes of the enclosure. This lets you keep the cover loose while still operating the monitor safely.
  4. Set Up Your Multimeter
    • Put it in DC mode, ideally at the 20V range.
    • Measure voltage as close to the monitor as possible, ideally at the 14-gauge red and black power wires.
    • Insert the leads directly into the connector for live readings.
  5. Run the Monitor to a Hard Stop
    • Move the monitor to full travel until it hits a stop.
    • This is when it pulls the most current, which will reveal voltage drops.
  6. Capture the Voltage Drop
    • Use your multimeter’s MIN/MAX feature to record the lowest voltage during operation.
    • This helps identify if voltage is dipping below acceptable levels (typically below 10.5V on a 12V system can cause problems).

Common Causes of Low Voltage

  • Loose ground connections
  • Undersized wiring between the power source and the monitor
  • Voltage drops due to long cable runs

How Pure Power Can Help

If you’re seeing unacceptable voltage drops, the best long-term solution may be TFT’s Pure Power.

What Is Pure Power?

Pure Power is an inline capacitor bank—a series of “super capacitors” designed to hold and release energy instantly. When installed between the power source and the monitor, it:

  • Smooths out voltage dips
  • Prevents shutdowns or glitches during high current draw
  • Works automatically—no setup required

Plug-and-Play Design

  • Uses Deutsch connectors for simple inline installation.
  • No programming or calibration needed.
  • Compact and rugged for in-field reliability.

Why It Matters

When voltage drops even for a fraction of a second (as fast as 100 milliseconds), it can cause serious problems. Most standard multimeters can’t catch these momentary brownouts unless they have a MIN/MAX capture function. That’s why both accurate testing and proper hardware support—like Pure Power—are critical for reliable firefighting operations.

Final Thoughts

Low voltage is one of the most common hidden faults in electronic monitor systems, and ignoring it can lead to poor performance or field failure. By using the right testing method and tools, and installing a stabilizing device like TFT’s Pure Power, departments and OEMs can ensure consistent, safe operation in high-demand environments.

 

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