Have been using Grinch/Dimmer for a couple of years OK starting at Ch1. I have now tried to set the start to CH 257 but cannot get it off CH1.
This is what I did...
I used Vixen 2, made a 5 sec sequence of 64 channels. Set all of Ch1 at 255, all of Ch2 at 2, all the rest of the channel grid at 0. Looped and clicked play.
With the Grinch/Dimmer powered up, a light on output A1 comes on full - so they are talking OK.

I Powered off dimmer, put J3 on, powered on Dimmer - got solid red led but no green no matter how long I wait.
Did I do it all correctly?
When in normal use, the green led flashes away as data is sent so it works. If I do a remove DMX signal/Power down/J3 on/Power up (to get CH default) I still get no Green Led.

Anyone had this problem?