Hi Bedifferent, how old is your Amplink, mines range from when they first came on the market, probably in the region of 5 years ago to the most recent which will be about 2 years old. The company used to be helpful but its attitude seems to have changed. I did a lot of bench testing on my Amplinks using a variable power supply at work, 2 of the older ones had triggers 1 and 3 completely disable, trigger 2 on all 3 still worked, the newest one only lost a ground trigger on 3. I think one of 2 possible causes, 1. They have changed chipsets and not tested with legacy models or 2. The new APP changes the switching parameters in the software. One of my triggers would only work above 17volts.