A Roku player that's on but shows no picture — sometimes with sound, sometimes a "No Signal" banner — is usually outputting a resolution your TV or the current HDMI port can't display. That's a Display Type mismatch, and it's a settings fix, not dead hardware. The good news: you can fix it blind, without seeing the menu.
The likely cause
If you get audio but a black screen, the Roku is almost certainly set to a resolution the port can't accept. If you get a hard "No Signal" banner, the TV sees nothing on that input at all — more likely a cable, port, or power problem. Either way, start by resetting the output.
Fix it
- Blind-reboot to reset the resolution. On the remote, press: Home ×5 → Up ×1 → Rewind ×2 → Fast Forward ×2. The Roku pauses, then reboots. (This is officially a system reboot, not a separate "auto-detect" command — but on restart the Roku re-runs its HDMI handshake, which clears most resolution-mismatch black screens.)
- Let the fifteen-second auto-revert save you. If you briefly see the menu, pick a too-high Display Type, and the screen blanks — don't touch anything. Roku reverts to the last working setting after about fifteen seconds on its own.
- Set Display Type sighted. Once you have a picture: Settings > Display type > Auto detect, or force 1080p HDTV if Auto keeps choosing a mode your TV chokes on.
- Reseat and re-port the HDMI. Move the player to a different HDMI port (ideally an HDCP 2.2 / HDMI 2.0+ port) and reseat both ends. Swap in a known-good, short certified cable if you suspect the cable.
- Power it from the wall, and 30 seconds off. Use the supplied power adapter into a wall outlet, not a TV USB port — under-powering a stick is a real black-screen cause. To power-cycle, unplug for at least 30 seconds before reconnecting.
- Go straight to the TV. If the Roku runs through an AV receiver or soundbar, connect it directly to the TV to test. A receiver in the chain can break the HDCP handshake and black out the picture.
When it's NOT a Display Type problem
Two different failures get mistaken for this:
- Purple screen / "HDCP error" (code 020): the link connected but copy-protection failed. Swap to a short certified cable, reseat both ends, try another port, and remove any receiver/soundbar/splitter so the Roku talks straight to the TV.
- Roku TV with a totally dark panel but working audio and a responsive remote: that's a backlight/LED failure (panel hardware), not a Roku output problem — no settings change will fix it.
FAQ
I have sound but no picture — is my Roku dead? Almost never. Audio-but-no-video on a player means a resolution mismatch. Blind-reboot it (Home ×5, Up, Rewind ×2, FF ×2) or wait out the fifteen-second revert.
What's the purple screen? An HDCP handshake failure, not a resolution issue. Use a short certified cable straight into the TV, bypassing any receiver.
Why does it work on one TV but not another? Different ports and panels accept different modes. A Display Type that's fine on one TV can blank another — set it to Auto detect.