Capture Card Black Screen or No Signal: Fixes

Work through these in order

1. PS5: turn off HDCP. HDCP is copy protection that blocks capture. The PS5 has to be connected directly to a TV or monitor to change it: Settings → System → HDMI → Enable HDCP off. Xbox Series X|S turns HDCP off for games by default; PS3 can't turn it off at all.
2. Check the cable direction. Console HDMI OUT → capture card HDMI IN; capture card HDMI OUT → TV or monitor. Swapped cables give a black screen on both.
3. Lower what the console sends. Set 1080p, turn off 120 Hz output and VRR, and try again. Many cards can't pass through or capture every 4K120 VRR signal.
4. Turn off HDR on the console if the card doesn't support HDR capture. Some cards show "no signal" rather than a washed-out picture when an HDR game starts.
5. Use a USB 3 port (blue or marked SS) and the cable that came with the card. Avoid hubs and front-panel ports.
6. Close other apps. Only one program can open the card at a time: OBS, Discord, the card's own app and browser tabs all count.
7. In OBS, open the Video Capture Device's properties and press Deactivate then Activate, or delete and re-add the source.
8. Try another HDMI cable. A cable that works for a TV can still fail at the higher data rates a capture card passes through.

Nintendo Switch 2

If the Switch 2 shows nothing through the card, set the card's EDID mode to Display (Elgato cards), turn off 120 Hz and the Switch 2's Match TV power state, and try another HDMI cable. The dock must be powered with its own adapter.