Hi all

I suspect this is a red herring but wanted to ask around to see if others encountered the same thing. This will be a bit of a long read, but please bear with me.

Sunday at the church I had some serious issues. I have two KWorld USB devices that I use to pull a live video feed into the computers so they display on the second monitor using Screen Monkey. Since installing these I simply power up the computers and launch Screen Monkey and poof! As long as I have a video signal, it presents. Sometimes I have to nudge the camera guy to futz with things on his end as I don't see a signal until he does. Originally I had only one of the KWorld devices, then later acquired a second for backup redundancy. When I only had one, I was constantly futzing with the main computer and disrupting things as I checked to see if the camera signal was ready. Now that I have two devices and two laptops, I just watch the second laptop (my personal laptop) to keep an eye on the video feed.

A bit of backstory. For the last few weeks I've noticed the wireless USB mouse was appearing to have issues. It would seem skittish as I tried to move it. Clicks weren't being responded to. Sometimes it would take two or three clicks to get Screen Monkey to fade in or out or to bring PowerPoint to the foreground to present slides. So it made things a bit difficult to work with. A week ago, things totally collapsed. NO mouse whatsoever would work or be recognized when inserted into the USB ports. I finally somewhat concluded that the USB ports had mysteriously failed on the church laptop. Oddly, however, the live video didn't miss a hitch and it was also connected to a USB port. Hmmm

Google research seemed to indicate that this sometimes happens on laptops with Windows 7 on them. Although I've never had it happen on my personal. The suggested remedy was to remove the battery from the laptop for about 15 minutes so things totally discharged on the laptop. Then reconnect it all. So I tried this and voila! Things seemed to be back to normal. I was relieved.

So Sunday comes and after the video guy hooks up I start checking for a signal. Nothing. Nada. End of story. I figure he just needs to tweak a setting. About 10 minutes before service begins I ask if he is going to connect. He says he did it a long while ago! So we quickly check cables and whatnot. Even disconnected the camera (about 50 feet away) and brought it directly to the media booth to test so as to eliminate the long cable span running up the wall and through the ceiling. Nothing still. I finally conclude that the video feed out on his camera either got disabled somehow or was fried. Seemed logical, since both PCs refused to present the signal. Then during service I begin having mouse issues again on the church laptop! Now I'm really thinking the USB ports are goners. But that failed to explain why my own laptop wasn't presenting video as well. It seemed very unlikely that both KWorld devices would fail together.

After service ended I was testing again and scratching my head. What was different? The only thing I could fathom that had changed was that we were in the new year. Hmmmm So I closed Screen Monkey, changed the date on my computer and restarted Screen Monkey. POOF! I had a Video Signal! At that point I concluded that there was some obscure date issue involved. Then I decided to repeat the steps. Unfortunately I was not able to repeat the condition. So the date thing appeared to be a red herring.

Still uneasy about using the church laptop. Wondering if things will be any different if I just remove the battery entirely and only operate on AC? Won't know until tomorrow night I suppose.

Thanks for allowing me to ramble... Rick ;)

My thinking is along the same line as Olie's: there's some electricity getting into your signals that shouldn't be there. The first suspect is generally the grounding of the various pieces of equipment. The remedy is either to get everything working on the same ground - or then to deliberately break the ground loop at some point. My experience with audio is that applying theory and science to this problem is less effective than applying trial and error. I guess your laptop isn't grounded anyway, but it will have other signal leads connected that are grounded (e.g. video out, sound, Ethernet...).

Have you changed any of the electrical or signal connections, e.g. added an extension lead? That actually applies to any equipment connected by wire in this system, e.g. even the mixing desk or some instrument connected to it - probably best to try debugging sometime when you can unplug as many things as possible. What is the video output of the camera (S-Video, Composite, HDMI...) and how is that signal getting to the KWorld USB video input (coax, CAT-5/6, CAT-5/6 with baluns...)? (We're just setting up a similar system, so I'd be interested in the details and your experience. And maybe all the reading up I've been doing can help you with your debugging.)

Good luck!
Steve

Thanks Rick, it's really useful to see what others are doing. Even if it does make us all want to get to play with the same toys :).

From your description it sounds like you're amplifying the composite signal after a long cable run. I'd have thought that it would work better to amplify before the cable run, so you're only amplifying the desired signal, not the interference too.

I've not seen any problems with Screen Monkey after the New Year. 2012 isn't a problem for computers like 2000 and 2038 could be - unless you're running a Mayan OS :).

I don't think the church laptop USB is the problem with your video disappearing. The video worked when the mouse was dodgy earlier, and on your own laptop the video failed at the same time as on the church laptop. It sounds like they are two separate problems (although there may be factors influencing both). Since video failed on both laptops at the same time, it's reasonable to assume the problem was with the signal they received. If you only had 10 minutes before the service, things must have been a bit frantic so it's possible there was something you missed in your initial debugging that was then corrected along the way, and things started to work again.

The only long shot I can come up with to explain everything - mainly by omitting all the actual details and using a lot of hand-waving to fill the gaps :) - would be that your problems are to do with a difference between ground potentials. The KWorld could output your laptop's different ground potential along the video lead to the camera, making it unable to transmit, so neither laptop would receive a signal. Closing Screen Monkey could reset the KWorld device, getting rid of the problem. Maybe winter has something to do with it, as the air inside gets drier making problems with static worse. I remember one gig last winter where I changed the mic and lead for a singer twice before we realised that the crackling sounds we heard were because of static from the fluffy top she was wearing!

To resolve any problems related to grounding, try and (1) reduce static problems through avoiding problem materials (e.g. nylon carpets) and by grounding things properly, and (2) avoid ground loops by making sure each piece of equipment only has one path to ground. There's a good discussion of ground loops here: http://siber-sonic.com/electronics/GL... and http://www.epanorama.net/documents/gr... (mentions them as a cause of computer problems, as well as the more familiar audio hum and video interference).