Direct answer
When a TV function works on another input, app or source, isolate that signal path before changing the whole television. For HDMI video handshake, first connect one source directly with a certified cable at a standard resolution.
What this covers
- HDMI video handshake with this exact failure state
- Diagnosis across direct TV connection versus receiver, switch, dock and cable path
- Customer-accessible observation, settings and external components
What it does not cover
- ×A displayed manufacturer error code with a different documented meaning
- ×Live electrical, sealed-system, internal battery-cell or gas repair
- ×A claim that every model exposes identical controls
Capture the exact failure state
ReversibleName the failing input, app or source and one that still works. Expected behavior: negotiate a stable picture and sound format after source or input changes.
Isolate the component boundary
ReversibleConnect one source directly with a certified cable at a standard resolution. Swap only the source, HDMI path, app or account while keeping the display and network unchanged. Boundary to separate: direct TV connection versus receiver, switch, dock and cable path.
Correct only the proven cause
ReversibleReplace the failed cable or intermediate path and update both endpoints. Repair the isolated source, app session, cable path or format mismatch.
Verify and stop safely
ReversibleRetest both the failing and known-working source after a full restart. Stop for a hot connector, bent socket, sparks or signal loss when the fixed port moves.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Exact questions
Common follow-ups
What should I check first when HDMI video handshake has this problem?+
Connect one source directly with a certified cable at a standard resolution.
Why not factory-reset immediately?+
The useful boundary is direct TV connection versus receiver, switch, dock and cable path. A reset can erase state without proving which side failed.
When should I stop troubleshooting?+
stop for a hot connector, bent socket, sparks or signal loss when the fixed port moves.
Answer for the exact device and software version shown above.