January 12, 2018 at 10:29 AM #96579
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!
January 12, 2018 at 2:40 PM #278108
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.
January 15, 2018 at 11:12 AM #278119
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.
January 22, 2018 at 10:30 AM #278157
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!
January 22, 2018 at 9:58 PM #278158
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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