One of my 14TH/sec S9s has been running at around 12TH/sec due to one ASIC card working at about half speed. The miner status panel showed 6 ASICs as missing (not X, just not there). Ok, fine. 12TH/sec beats 0Th/sec for several months of warranty repair, so I just left it running.
One of the regulars here has repeatedly suggested downgrading to the 0417 firmware, which I did on this machine (and many others that were under-performing for no obvious reason). Several of those under-performers came up from 13.3-13.5 back into the 13.8-14.1 range, which I considered a nice win! Surprisingly, the unit with the missing ASICs came back with all of them showing and crunching along at its rated 14TH/sec! Very Cool. Thank you Fanatic26!
Alas, that was yesterday... today I came in to see the missing ASIC unit running with only 2 hash cards, the other was visible, but not doing anything. No change after a reboot. For hells bells flashed it back to 1117 and it came fully up, but now thinks its a 13.5 TH/sec machine.
After running for an hour, the problem card is visibly under-performing:
http://puu.sh/zrgzx/f64f357763.png, but doing better than it used to do by a bit.
Going to just let it run so long as all 3 hash cards are doing something.
Just thought I'd share how fickle these units are.
ps. Should add that the APW3++s are pretty fickle too. I think. Seems like I can swap power supplies and sometimes problems go away for awhile. Sometimes those swapped out power supplies run other S9s just fine. Sometimes not. I have (3) out of (103) that definitely have problems powering all three cards (and yes, I'm at 220V). Fortunately, at todays $2320 miner price vs. $105 power supply prices, its, IMHO, just silly not to have a few spare power supplies if you have more than just a single miner.
Oh, for those of you in the northern hemisphere currently using outside air for cooling, I can definitely state that APW3++ power supplies do NOT like 0C air - or at least most of them don't. I powered up (80) machines back in early December with temps between 0-2C and about 1/5th of them came up (the lights on the S9s would not even blink on the other 4/5th and swapping in a pre-warmed power supply would fix the problem.). Fortunately I could open up my hot aisle and allow some air recirculation (now regulated with a thermostatically controlled exhaust fan that keeps my cold aisle around at least 10C). As the temperature warmed, more and more of the power supplies started working. It seems that 10C is a more realistic minimum for them. Once running, they generate enough internal heat to stay happy. I only state this since they are rated for a running minimum temp of 0C.
