i have 8 rigs running, all with a 1600 T2 EVGA PSU, gigabyte mining motherboard, 1070 minis and SRS Digich risers.  risers are powered directly by PSU and no sata is used.  These things have been running over 6 months with zero problems until 2 days ago.  one of the rigs shut down and when i powered it back on i noticed only 5/6 risers  were getting power.  i swapped out the riser and when i turned the machine on all 6 lights were on then instantly i heard a sizzle, smelled something burning and it powered down.  turned it back on and again 5/6 were only powered.  the riser that keeps going out is attached to the pci xpress 16slot.  i used compressed air and blew out anything that could be shorting it, swapped out cables, risers and components and still same thing happened.  any ideas??