Need help with possible static? Displays keep resyncing.

Videomaker – Learn video production and editing, camera reviews Forums Specialty Topics Worship Video Need help with possible static? Displays keep resyncing.

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    • #96579
      Avatarphuzzyday
      Member

      Hello everyone!  I appreciate your willingness to help unknown people like me!

      I am trying to help with a problem.  House of worship.  I am doing some research to see if I can get any input.

      It seems that whenever a laptop is touched, the TV's at the front of the house are having to resync themselves, and make a big flickering distraction.  As if it's static.

      We have a sound desk at the back, with a laptop, and a mixer, etc.  The laptop has a video connection to two large LCD tv's at the front of the hall, about 30 feet or so away.

      From the HDMI port on the laptop, the signal is converted via a box into the digital coax type of video transmission cable.  (I forget the name, and I am rushing a bit.)  That cable goes to the front, and a splitter divides the signal to the tvo tv's, each having a converter back to HDMI. (Possibly converts to HDMI before splitting, I am getting the second hand.)  We have mic stands on the stage, as usual, wired XLR balanced, yadda..

      I think that is everything…  and I hope this is the place for it…  if not, could someone help me find the right place?

      I don't have direct control over the system anymore, although I installed the sound part years ago.  I have been asked to see if I can find, for the lack of a better term, some ideas with influence… ?

      Does anyone have any good ideas re: what could be causing this, and, even better, something that could SOLVE it?
      I thought maybe a better ground on the laptop, or a static pad for it to sit on..  if it even IS static..

      Thanks everyone for your input!

    • #278108
      AvatarJackWolcott
      Participant

      Troubleshooting a setup like you describe must be done systematically, by isolating each element in the system. I would start by connecting the laptop directly to each television set and see if the problem exists. Test this against every laptop-to-TV connection possible — that is, HDMI to TV, RCA to TV is that's available from the laptop, etc. If everything is o.k. you can rule out the laptop and begin isolating the converters, one at a time. Be sure to include the splitter in your tests. Check every wire and connection.

      Good luck.

    • #301448
      Avatarphuzzyday
      Member

      Great Advice.  Thank you.  How do you feel about the static theory?  If we started from that hypothesis, how would we solve such a thing?  Extra ground connections on the equipment, perhaps even grounding the operator somehow before he touches it?  I will pass the other ideas along, but they are interested in this question also.

      One person suggested that we could not connect the laptop chassis to a ground cable as a troubleshooting idea, as it would cause a ground loop.  I don't think that's what ground loops actually are, and it's supposedly grounded through the power adapter anyhow…  I believe..  however if that was not a favourable enough path, a second one with less resistance might help.  Any thoughts?

      Thanks SO much for your time!

      PD.

      EDIT – Are you thinking that a weakness in the system along the line could leave it succeptible to static itself?  In that instance, the preventative measures I referred to would only work toward curing a symptom..  not the problem… if at all.  Am I on the right track?

    • #278119
      AvatarJackWolcott
      Participant

      Static, as I understand it, is the result of electrical disturbances in the line. So I go back to my original post: it would seem that there is a short, or inperfect circuit/connection in the system that is causing an electrical discharge — static. Trouble shoot as suggested.

    • #301447
      Avatarphuzzyday
      Member

      Thank you very much.  Again, I appreciate your input, and recognize your experience!!  I hope it didn't seem like I was second guessing.  Afterwards I thought about what you had suggested, and I sort of came to that very conclusion.  Thus the edit.  I will update if approptiate!  Prety happy to have found someone with so much background!  

      Appreciate you giving your time.

      Phil D

    • #278157
      Avatarphuzzyday
      Member

      I have been invited to be part of a team to diagnose this problem.  Your suggestions helped me get there, thank you.

      A question for clarification though, in anticipation of future conversations…  If all the equipment was good quality, and up to standard, including properly terminated, connected, and undamaged cables, could there be any other installation errors, or other outlying circumstances which could cause a weakness in the system such as this?  Perhaps cable proximity rules or anything?  Ground loops?

      Thank you again for your invaluable advice!

    • #278158
      AvatarJackWolcott
      Participant

      Outside RF transmissions — e.g., a HAM operator who keys his radio from time to time. Some piece of equipment in the hall that generates an electrical connection of some sort — e.g., a furnace that turns on from time to time; air conditioning doing the same; a sump pump, etc. Problems in the hall's electrical circuits at the distribution panel or from connection to the main electrical line.

      It is possible — remotely — that a cell phone or similar device is causing this, and equally possible — remotely — that the laptop is at fault.

      I wish you well with finding a solution. This is the kind of problem I would typically turn over to an electrical/electronic specialist from the community.

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