I just started getting "found 0 chip(s)" error in CGMiner 4.11.1 and the r606 turning into a zombie; it has been mining steadily since august. i tried to restart cgminer, changed the power connector and the usb cable, but the same error persists. I am using Ubuntu 18.04.3LTS.
update - i am running two r606, but just one is borked. The other one is running well at 800mhz since it was turned on.
i downclocked my settings to 700mhz/860mV, and after a few days of "resting" and a few false starts ("0 chip"/zombie errors), the miner started hashing again.
Not sure what happened but i will try to play with my clock speeds some more later. it is running again so w00t