Common Problems with HDMI


Problem 4: Pixel Errors or “Sparkles”

Symptom: Sparkles occur in the family room display from the STB.

Solution: This is the often the most difficult problem to isolate the cause. A partial list of possible causes includes:

  • Excessive dielectric loss through HDMI cable or HDMI extender or repeater device
  • Excessive skew on the TMDS pairs
  • Poor quality HDTV (poor equalization)
  • Pre-HDMI 1.3 source without pre-emphasis

There is a sequence of tests that need to be conducted to isolate the problem. First, conduct a cable/repeater test with the objective of determining if the HDMI cables to and from the matrix switch and the switch itself are passing good video. If this test passes then the most likely cause is the Extender.
Second, run a test on the Cat extender and then the Cat 5 cable itself by swapping them out. If the tests fail then you should perform individual tests on each cable. If one fails, replace it. If they do not fail, replace the matrix switch.

This is a great list to help troubleshoot common issues with HDMI.



About Matthew Peterworth

I currently work as a Technology Specialist at Henderson Engineers in Kansas City – a Mechanical-Electrical-Plumbing (MEP) design firm. Prior to that I was a Project Manager for Information Technology Services (ITS), the central IT department at the University of Texas at Austin. As of July 2008 I am a Registered Communications Distribution Designer (RCDD) through BICSI. And as of June 2011 I am a licensed Professional Engineer (PE) in the great state of Texas. Please follow me on Twitter @mpeterworth.

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