anthony_flores Posted January 1, 2009 Share Posted January 1, 2009 <p>Funny thing:<br> When I have my camera (D300) tethered to my laptop via USB and my flash sync cord connected to my Monolights, the strobes will fire rapidly and repeatedly on thier own, until disconnected. I have replaced the sync cable and the USB cable and I've tried novatron and alien bees monolights on both D80 and D300 cameras. All with the same results. The only commonality seems to be the Nikon brand. I've yet to try this with canon.<br> I figured out it was something to do with USB while shooting last night. On a gut instinct, I yanked out the USB cable and tried it again. It worked fine. <br> So my question is, has anyone here experienced the same thing, or did I just get 2 bad cameras?</p> <p>Anthony Flores</p> Link to comment Share on other sites More sharing options...
bob_sunley Posted January 1, 2009 Share Posted January 1, 2009 <p>Ground loop, I'll bet your laptop is running off it's a/c power pack.</p> Link to comment Share on other sites More sharing options...
Matt Laur Posted January 1, 2009 Share Posted January 1, 2009 <p>I would be very careful. Is your laptop grounded? Are the monolights grounded? To the same outlet/ground?<br /><br />Incidentally - are you shooting tethered, or just transferring data? A card reader sounds like a really good idea before the camera, or the laptop, or both take an expensive hit.</p> Link to comment Share on other sites More sharing options...
anthony_flores Posted January 1, 2009 Author Share Posted January 1, 2009 <p>Bob? Are you a hammie? lol. I'm a general class myself (KE5UYI).<br> I never even stopped to think about that. It makes perfect sense. Recalling, I believe the times it has worked, it has been on battery power. Most laptops have GL issues. (poor design). I am used to GL issues on radio equipment, I just had a mental block and didn't transfer that knowledge to camera equipment. Brilliant!<br> Thanks!</p> Link to comment Share on other sites More sharing options...
bob_sunley Posted January 1, 2009 Share Posted January 1, 2009 <p>No, I'm a network guy and have had to deal with the GL and floating ground issues for years. Just image what problems 30vac and 400ma between two building ground circuits can create, besides give you a decent shock.</p> <p> </p> Link to comment Share on other sites More sharing options...
reichard Posted January 2, 2009 Share Posted January 2, 2009 <p>Get an inexpensive isolation transformer -- that'll fix your issue -- 73's de n3izc</p> Link to comment Share on other sites More sharing options...
anthony_flores Posted January 2, 2009 Author Share Posted January 2, 2009 Haha, and now the Hammies come out to play :). Reichard, According to QRZ you're out in the sticks of Penn. I bet there's some great images to had up there. And probably nobody to complain about setting up a 300' tower and a yagi :) Link to comment Share on other sites More sharing options...
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