Have a 70d and a monolight setup

[mhoffman300]

Have a 70d and Monolight setup and first time I have tried to use it with new camera.  It worked with my old Nikon camera, but now it just seems to fire bright all the time.  Picture is always over exposed to the max.  No matter what I do with the settings.  This has a hotshoe wired set up and I have tried 3 different lights.  Every different exposure setting. Not sure if there is some TTL setting that I am missing.

Any help appreciated

[Skirball]

What mono do you have?  It worked in TTL with Nikon?  There are only a few TTL monos as far as I know.  Is the mono TTL compatible with both Canon and Nikon?

Most monos are manual, in which case you have to move down the power.  If it is in fact a TTL mono, then it's likely the TTL cord.  Most cords are specific to the manufacturer.  They do make cords that are supposed to work with Nikon/Canon/Fuji, but I've heard of compatibility issues with certain flashes.  I would first verify that your mono is Canon TTL compatible.  Then I'd have a look at the cord.

Lastly, what camera settings are you using?  It's possible, if your mono is strong enough, that even ISO 100, and f/22 could be overexposing if you're not using modifiers.