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??
Take the gpu, riser, and all associated cables off and inspect them all. Inspect all of the connectors to make sure everything is going well. Then check your actual PSU and the cable going into the wall. Check the wall outlet too. Look for split cables and discoloration/burning at all of the connectors and wall socket. Replace anything that needs replacing. Then see if you still have the problem.