last night I switched pools in D3 miner, saved configuration, then third chain didn't start to mine at all, it showed around 62 O, after 5 minutes O changed to X. This happens for the first time. Restart didn't help, so I shut it down for night and bring it to the apartment.   Next day I unplugged all cables (from PSU and hashing boards), refitted them again, start miner and third chain is back!

Don't know what happened, maybe it was too cold for antminer, I kept it at the attic and there is only 3 celsius degree at night.

What do you think about coldness - could it harm antminer ? I think if you leave it alone without interrupting it should be fine.

I'm on stock firmware (last one) and I  was just about to try Blissz  upgrade