check power supply to alphapix, is it actually on, is ethernet cable plugged into computer and alpha.
Do you have multimeter, check for power & data on each output.
what version of xlights are you running, if you can ping the controller then network should be good.
Have you re-rendered all the sequences on the new install.

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Try using xlights (turn on lightbulb) and see if its xlights, if XL works then try xschedule.
Cheers Boof63