I own a 5D mark 2 and 3 and a Phottix TR90 intervelometer.
I am trying to do a timelapse in manual mode.
I set up the intervelometer to fire every minute.
I hit the start button, and... nothing.
It wont trigger.
Then I leave the settings on both camera and intervelometer... and simply switch the camera into Automatic mode... and start the timer on the intervelometer, and it works just fine... triggers a shot every minute.