Canon 5Dmkiii weird miss firing with sync cable and strobes


EOS M6 Mark II
Oct 9, 2012
West Coast
Hoping someone can help me out. Recently got a bunch of new equipment and finally some time to set it up and test it out. However, ran into some problems I couldn't figure out.

Canon 5D mk iii
Canon 7D
Interfit stellar XD strobes
Canon 430 EX
Cactus V5 wireless triggers

So I set up a my gear to shoot some wine bottles for this photigy course I am doing. I set my 5D to full manual, silent shoot off, shutter at 1/160th and tethered it to my MBA and was using live view and eos utility. Hooked one strobe up to my camera with sync cable. Shooting, everything was good. I was messing around with various positioning etc to get the reflections I wanted and back to shooting. Then for no apparent reason, the strobes stopped firing consistently. maybe 1 in 4 shots would fire but random. I checked cable, even switched to a different strobe. no difference, inconsistent and very poor results. I turned off liveview, disconnected from my MBA and same results. Hooked the sync cable up to my 7D and worked 100%. With either camera and my 430 EX I could trigger them optically every time, not one misfire.

Today, went back to shoot some more and was doing fine, 100% after about 50 shots, then it started misfiring again. Around the same time, I thought my 5D shutter sounded like it was in slow motion too but maybe that was just me being pissed off. Again my 7D shot 100% when I tested it... don't get it. The 5D may of heated a bit but liveview doesnt display on the LCD when teathered so it isnt working as hard. Could that have something to do with it?

Anyway, shut everything down, went out and bought some Cactus V5 wireless transceivers. Didnt want to spend a lot and these had very good reviews.

Came back hooked them up to my 5D and stobes. checked channels and right settings. no go, wouldnt fire strobe on shots. Pressed the test button on transceiver on 5D and fired the strobe. When I click shutter, green light on both transceivers light up but dont fire. I hooked it up both to sync cable and hotshoe with no results. I tried with my 7D and no results. I hooked the cactus V5 to my 430EX and that worked 100% and optically fired the strobes every time.

Not sure what is going on. Had such good karma all week but I did decline to jump start a lady's car just before heading home to shoot, was too excited to get all this going... damn u Karma.