USB 3.1 Troubleshooting

Unplug the filter and plug it back in.

This step solves most issues, and it confirms the filter is receiving power.

This solves most problems. The ACTIV USB 3.1 is powered through a small DIN connector on the filter. Unplug the DIN connector, wait about ten seconds, and plug it back in. Press firmly until the connector clicks fully into place. The Power LED (red) should come on right away. If your peripheral uses USB Power Delivery above 5VDC, the High Voltage LED (yellow) will also light. The yellow LED stays off for peripherals that operate at the default 5VDC, which is normal.

If the Power LED does not come on after reseating the DIN connector, check that it's fully seated; the connector requires firm pressure to click into place, and a partial connection can prevent power from reaching the filter. If the Power LED still doesn't come on after a confirmed full seating, the issue is on the power side. The ACTIV USB 3.1 uses a 24V / 3.75A adapter. If you have a multimeter, you can verify the adapter output reads 24VDC or slightly higher, but be careful when probing the DIN connector pins; the pins are close together, and while the adapter has built-in short-circuit protection, careless probing can produce misleading readings. If the adapter output is correct and the Power LED still doesn't come on, contact us; the filter may be faulty.

Reset the filter and the peripheral together.

This step clears any USB enumeration error on the peripheral that the filter reset alone won't fix.

If just resetting the filter didn't help, the peripheral (the device on the protected side, i.e., the printer, drive, instrument, or accessory) may be stuck in an enumeration error from when the connection briefly dropped. Unplug the filter and turn off or unplug the peripheral. Wait ten seconds. Power the filter back on first, give it a few seconds to come up, then power on or reconnect the peripheral. The host will re-enumerate the peripheral on reconnection and the connection should resume normally.

Restart everything from the host and working downward.

This step restarts the chain in the right boot order. USB hosts enumerate downward to peripherals, so the host has to come up first.

If neither reset worked, restart everything starting from the host and working downward. Power off the peripheral, then the filter, then the host. Wait ten seconds. Turn things back on starting from the host, then the filter, then the peripheral. Always from the host downward, with each piece given a few seconds to come fully online before turning on the next.

Verify each cable works.

This step confirms both USB-C cables are functional. A faulty cable can mimic a faulty filter, so cable verification has to happen before any conclusion about the filter.

USB-C cables vary widely in capability. Not every USB-C cable supports SuperSpeed (10 Gbps) or full Power Delivery, even if the connector looks identical. Long cables in particular often lose data rate or fail to negotiate at the higher speeds.

For each of the two cables connecting the filter (one host-side, one peripheral-side), test it independently by connecting the host directly to the peripheral with that single cable, no filter in the chain. The peripheral should enumerate and operate normally. If a cable fails this direct test, that cable is faulty; replace it. Repeat for the other cable. Both cables must pass this direct test before continuing.

Look at both USB-C ports on the filter while you have it disconnected. Make sure they are clean, unobstructed, and free of any foreign material (lint, dust, or debris in a USB-C port is a common cause of intermittent connection problems). Reseat both cables firmly when reinstalling.

Confirm the filter is the cause.

This step isolates the filter as the failure point, after the cables have been verified.

With both cables confirmed working in Step 4, reassemble the system: host, cable, filter, cable, peripheral. If the system now fails, the filter is the cause.

If your installation is mounted through a shielded enclosure penetration and reassembly testing requires temporarily relocating equipment or running cables differently than the permanent install, do whatever it takes to perform the test. Use a longer temporary cable, move the peripheral, or set up a bench test outside the chamber. The verification has to happen; the filter is either the cause or it isn't, and the test is the only way to know.

Contact us.

If you've worked through Steps 1 through 5 and the filter is the cause, contact us. We'll arrange an RMA and take it from there. All ACTIV USB 3.1 filters carry a two-year warranty from the date of first sale. See the warranty page for details.