My CEC Adapter Isn’t Working — Where Do I Start?

Last updated:

This article helps you identify what's wrong and points you to the right fix. Work through the checks below in order — most issues are resolved by step 3.

Step 1 — Check the Physical Connection

USB-CEC Adapter: confirm cable orientation The adapter has three ports. The PC port connects to your computer (source), the TV port connects to your display (output), and the Data mini-USB port connects to a USB port on your PC. Swapped HDMI cables are the most common cause of a completely blank screen.

Intel NUC CEC Adapter: confirm the cable harness is seated The internal adapter connects via a cable harness specific to your NUC generation. If the harness is not fully seated at both ends the adapter will not be detected. See the Hardware Setup Guides section below for your generation.

Confirm the USB data cable is connected (USB-CEC Adapter only) The adapter requires the mini-USB data cable to be plugged in — not just the HDMI cables. Without it, the PC cannot communicate with the adapter and it will not appear in libCEC.

Step 2 — Confirm libCEC is Installed

All Pulse-Eight CEC adapters require libCEC to be installed on the host PC. If it has never been installed, or was installed incorrectly, no CEC commands will work.

Not sure if libCEC is installed? Open the Start menu and search for CEC-Tray. If it doesn't appear, libCEC is not installed.

→ How to Install libCEC (Windows)

Step 3 — Confirm CEC is Enabled on Your TV

HDMI-CEC must be switched on in your TV's settings menu. Every manufacturer uses a different name for this feature:

Manufacturer	CEC Feature Name
Samsung	Anynet+
LG	SimpLink
Sony	Bravia Sync
Panasonic	VIERA Link
Philips	EasyLink
Toshiba	Regza Link / CE-Link

Consult your TV's settings menu and ensure the feature above is enabled. On some models it is off by default.

Step 4 — Identify Your Specific Symptom

If the adapter is connected, libCEC is installed, and CEC is enabled on the TV but something still isn't right, find your symptom below:

The adapter is not detected / CEC-Tray shows no adapter

Check Device Manager for a Pulse Eight CEC Adapter entry under Ports (COM & LPT). If it appears with a warning icon, reinstall libCEC.
Try a different USB port on the PC.
Confirm the firmware is up to date — an older firmware version can cause detection failures.

→ Upgrading the Firmware of the CEC Adapter

The TV won't turn on when the PC boots

This requires firmware v9 or newer and a correctly configured power-on method.
The USB port must lose power when the PC shuts down — if it stays powered, the adapter cannot detect the boot event. Disable USB charging / USB power in S5 in your BIOS if needed.

→ Which TV Power Control Method Should I Use?

→ How to Turn Your TV On at Boot Using CEC-Tray

→ How to Turn Your TV On at Boot Using a Windows Batch Script

CEC-Tray won't open or throws a DLL error

This is almost always caused by copying the CEC-Tray executable to another location instead of creating a shortcut. The executable depends on DLLs in the same folder and will fail if moved.
Delete any copied executable and create a shortcut to the original instead.

If a full reinstall is needed: → How to Install libCEC (Windows)

The TV turns on but the PC also wakes from sleep unexpectedly

→ CEC Adapter — Using the LibCEC Standby Monitor

The TV goes to standby when the PC's screensaver activates

This is the screensaver / inactivity standby feature in CEC-Tray. If you want to disable it, open CEC-Tray, go to the Power Control tab, and set the standby delay to Off.

→ CEC Adapter Screensaver / Inactivity Standby

Panasonic TV media control buttons are not working

→ Panasonic TVs — Media Control Buttons Not Working with CEC Adapter

I'm on an LG TV and CEC stopped working after a firmware update

There is a known issue with LG WebOS 4.0 (software version 05.10.25, released November 2019) where CEC stops working on HDMI 2 (the ARC port). Connect your device to HDMI 1 instead.

→ NUC CEC Issue — LG WebOS 4.0 (SW Version 05.10.25, November 2019)

I'm not sure which adapter or method is right for my setup

→ Which TV Power Control Method Should I Use?

→ Intel NUC CEC Adapters — Hardware Compatibility and Legacy Notice

Hardware Setup Guides

If you are installing or reinstalling an Intel NUC CEC Adapter, use the guide for your NUC generation:

Not sure which NUC generation you have? Check the model number on the underside of the unit. The generation is the number after "NUC" — for example, NUC8i5BEH is 8th generation.

Still stuck? Contact Pulse-Eight support.
Let us know your adapter model, your operating system, and a description of what happens (or doesn't happen) when you launch CEC-Tray.

UK: 01202 413 610 | US: (858) 748-8250 | support@pulse-eight.com

Was this article helpful? If not, submit a support ticket and our team will help.