Black screen or no sound: fixing picture and audio problems

The build seems to start (lights blink, maybe you hear a menu sound) but the TV shows nothing. Or the picture is perfect and the room is dead silent. Both are really common and almost never mean the build is broken. It is usually a cable, a port, a resolution or one setting.

If nothing happens at all when you power on (no lights, no logo, a rainbow screen), start with Build won’t boot instead. This article is for when the machine is clearly alive but the picture or sound is missing.

Part 1: Black screen or “No signal”

Check the simple stuff first

1. Right input on the TV. Step through each HDMI input with the Source button. It sounds daft, but it catches everyone.
2. Right port on a Raspberry Pi 4 or 5. These have two tiny micro-HDMI ports. Use the one nearest the USB-C power socket (called HDMI0). Many builds only send a picture to that one.
3. Cable and adapter. Cheap micro-HDMI adapters and very long cables cause no end of trouble. Try a different cable, ideally a direct micro-HDMI to HDMI lead, and plug straight into the TV rather than through a soundbar or switch box.
4. Plug the HDMI in before powering on. A Pi checks for a screen as it starts. If the TV was off or unplugged at that moment, it may not send a picture. Turn the TV on first, then power the Pi.
5. Give first boot time. Many builds resize themselves on the very first start and can sit on a black screen for several minutes. Leave it five minutes before deciding it has failed.

Resolution problems (picture flickers, goes black after the logo, or “mode not supported”)

Resolution means how many dots make up the picture, for example 1920 x 1080 (1080p) or 3840 x 2160 (4K). Some TVs and monitors, especially older ones or ones running through a capture card or switch, will not accept every mode, and you get a black screen.

• Batocera: press Start to open the main menu, go to System Settings and look for Video Mode (the wording can shift a little between versions). Pick a standard mode such as 1920×1080 at 60Hz rather than “Auto”. If you cannot see anything to change it, connect the build to a different TV or monitor that does show a picture, change the mode there, then move it back.
• RetroBat: it runs on Windows, so it uses your Windows display. Set the resolution in Windows first (right-click the desktop, Display settings), and check RetroBat’s own video options in its main menu.
• 4K TVs: running a Pi at 4K is hard work and some builds misbehave. Forcing 1080p usually fixes it and games look just as sharp, as retro games are tiny anyway.

Raspberry Pi config basics (only if the above did not help)

On a Pi, the boot part of the card holds a small text file called config.txt (on some builds, settings live in a similar file such as batocera-boot.conf or recalbox-user-config.txt). Put the card in your PC, open the small boot drive that appears, and you will see it. Copy the file somewhere safe first so you can undo any change.

Lines that start with # are switched off. Removing the # switches them on. The usual helpers are:

• hdmi_safe=1 forces a basic, safe picture mode. Great for proving the Pi works at all.
• hdmi_force_hotplug=1 tells the Pi to send a picture even if it cannot detect the screen.
• hdmi_drive=2 forces “full” HDMI mode, which carries sound as well as picture (more on that below).

These options apply to older Pi setups and some builds ignore them, especially on the Pi 5, so check the build’s post before you start editing. Change one thing at a time, save, put the card back and test. If you get a start4.elf is not compatible message, that is a firmware issue with its own fix: see start4.elf is not compatible.

Part 2: Picture fine, but no sound

1. Volume and mute. Check the TV volume, the TV’s own audio output setting (TV speakers versus optical or soundbar) and the build’s volume in its menu. Some builds start quietly.
2. Pick the right audio output. This is the big one. The build may be sending sound to the headphone jack instead of HDMI.
   • Batocera: main menu (Start), Sound Settings, then Output Device. Try each HDMI option in turn and test with a game.
   • RetroBat: uses the Windows sound device. Click the speaker icon in the Windows taskbar and choose your TV or monitor as the output, then check the sound settings in RetroBat’s main menu.
3. HDMI in “DVI” mode. Some screens make a Pi think it is talking to a computer monitor with no speakers, so it sends picture only. The hdmi_drive=2 line above fixes that on builds that use it.
4. Sound in the menu but not in games (or the other way round). That points to one emulator’s settings rather than the whole build. Check the build’s post: some builds set specific audio options per system.
5. Through a soundbar or AV receiver? Plug the HDMI straight into the TV to test. Receivers can be fussy about the audio format.

Still stuck? Comment on the build’s post with your device, TV and cable, or ask in our Discord. Also see Raspberry Pi basics and Your first boot.