I've tried every possible combination of data cable / AUC converter / PSU (all supplied by 220v) / controllers / internet connections...... - every swap out was done with working items from an already operating A-821. Every swap out resulted in the A-821 restarting successfully. So no faulty hardware/equip there.

I have used several SD cards updated to the latest 841 firmware in several Raspberry Pi 3 Model B. (openwrt-brcm2708-bcm2710-rpi-3-ext4-sdcard.img).

The best I get is a constantly cycling A-841. The same results individually on both of my new A-841s.

I believe my issue is related to the following (copied from the CGMiner API log) (as if I really know anything):

******************************************
[Firmware Version] => Avalon Firmware - 20180305
    luci: 62d814c
    cgminer: b5b497e
    cgminer-packages: 960e108
Socket connect failed => Connection refused
******************************************

It has to be something on my end - hopefully someone can help me with this (internet connection / controller firmware??)

Thanks in advance