Most home-theater problems fall into a handful of buckets. Pick the one that matches your symptom and jump straight to the fix — and before anything else, try the two moves that resolve more issues than any single setting: power-cycle the gear in order (unplug for 30+ seconds, power the TV first, then the source), and swap the HDMI cable if there's any picture or audio fault.
No picture / black screen / "No Signal"
It's almost always the input, a marginal cable, or a failed handshake — not a dead panel. Confirm the right input, reseat and swap the cable, try another port, and power-cycle in order. By brand: Samsung, LG, Sony, Vizio. For a console: PS5, Xbox Series X. For a streamer: the no-signal checklist.
No sound, cutouts, or no Atmos
Audio over HDMI runs on ARC/eARC, and the fixes are about the port, CEC, and the TV's audio output. Start with ARC vs eARC and ARC/eARC no-sound quick fixes. For Atmos specifically, Dolby Atmos not working. Remember: optical can't carry Atmos — only eARC does.
Washed-out color or HDR that won't engage
That's a per-port enhanced-mode setting (Input Signal Plus / Deep Color / Enhanced format / Full UHD Color) plus the right cable. See the HDMI picture guides for Samsung, LG, Sony, Vizio, and TCL.
Streaming buffering or apps misbehaving
Usually the network, or an app that needs a reinstall. See streaming buffering & Wi-Fi fixes and smart-TV app crashes / missing apps.
Power, restarts, and protection mode
A TV stuck restarting or a receiver shutting off usually responds to a power-drain (unplug, hold the power button 30 seconds). A receiver that blinks and shuts off is protection mode — almost always a speaker-wire short. See the AV receiver error reference.
Browse by category
For everything else, the category pages collect the rest: TVs, Soundbars, Streaming devices, Receivers & amps, and Cables & connections.
FAQ
What's the one fix that works most often? A power-cycle in order (unplug 30+ seconds, TV first then source) for any glitch, and an HDMI cable swap for any picture/audio fault.
My problem is intermittent, not constant. Intermittent black-outs, flicker, or audio drops are almost always a marginal cable or a re-negotiating handshake — swap to a certified Ultra High Speed cable first.
Where do I start with no sound? Check the TV's audio output is set to the soundbar/receiver (not TV speakers), CEC is on, and the cable's in the ARC/eARC port. Then the ARC/eARC guides above.
It's a power or restart problem. Power-drain the device (unplug, hold the power button 30 seconds, use a known-good outlet) before assuming a hardware fault.