Interesting Courtney issue

[swanseamale47]

During the week we had a really busy day, this ment a lot of our gear being used, because of this I had to dig out my old Courtney flashes for an outside venue job.
I set it all up in the studio first and tested it all ok, get to the venue set up, no flash, by that I mean it's fires fine from the test button, it fires fine if I use a hot shoe flash and slave them, but noithing with the sync lead, changed the lead still nothing, changed the hot shoe adaptor still dead.
Tried sync lead on flash meter works fine, very odd, tried sync lead in the camera PC flash socket (which is hidden under a cover) works perfectly.
Now heres the problem, I'd tested the flashes with a Nikon in the studio (it was laying around handy) but I was using Canons on the day, and couriously it seems the hot shoes on some Canons have a different polarity to most other cameras, I made up a reverse polarity sync lead (swap the wires around lol) and it works faultlessly every time, how odd.

 

[classcams]

I have a few Courtenay flashes from the old days. The trigger volts altho being less than twenty volts are negative polarised (-20v). The gadget I made has an SCR to trigger the the flash where in the normal convention the anode is positive. Yet with the negative voltage on it, it still fires. I also have a studio flash with a positive trigger voltage on it. This also fires OK. also how very odd. Both my Nikon D90 and Canon 5D When using on board flash fire two flashes on manual, so the first flash has to be ignored or fit an old single pin flashgun on to the hotshoe. But you have to ascertain the trigger voltage is low.

 

[swanseamale47]

It's not set to give a preflash for focus or redeye is it?

 

[classcams]

Both Canon and Nikon have a little flash for red eye, independant of the main flash. Only onboard flash or makers own flash will set for flash value. A third party flashgun just blasts away.