I managed to connect a Chromecast 3° gen o my old sharp Aquos tv but it just shows the boot animation and then a black screen,
The Chromecast is connected and working and when I try to cast from YouTube or other apps only the audio is working
Thanks for reaching out. Let's sort this out.
Quick questions: is the Chromecast plugged in correctly to the TV and power source? What's the LED status on your Chromecast?
Please try to reboot your Chromecast. If the issue still persists, check this support website article and choose one that best describes on your TV screen.
Let me know how it goes.