Two of my new SP-30's are not going over 2TH for some reason. I have spoke to my hosting in Michagan and he says this seems to be an issue with many of the SP30's they've received. Are SP looking into this issue? We are losing out on the mining.
First, check the PSUs. Do a long power cycle (remove power for 30 seconds, plug back in). If one of the Emerson PSUs has a flashing green or flashing orange light consistently, then it needs to be replaced. If you have Murata PSUs, then I don't know offhand what the failure mode LED pattern is, but it's probably similar. If it's consistently one board that's not starting up, and you suspect the PSU is the problem (e.g. if you see "Board not present" messages in the event log), then you can try swapping the top and bottom PSUs with each other to see if the problem follows the PSUs or if the problem stays with the board.
If the temperature is low, then the DC2DC converters might be suffering from the temp underflow bug and falsely reporting a temperature around 250°C. Take a look at the ASIC stats page and look at the number on each line before "] ASIC:[". If any are above 240c, read
https://bitcointalksearch.org/topic/m.9158199.
Occasionally, a machine will have a bad loop or ASIC that causes the whole board to malfunction. You can often rescue these machines by marking the ASIC as disabled or (in the 2.4 firmware series) marking all three ASICs in the affected loop as removed. You can sometimes find out which ASIC or loop is the problem by reading the events log closely (usually the stuff near the bottom, which is the output of miner_gate_arm) or by watching the ASIC stats screen closely. If that isn't informative, then the other strategy is to simply mark everything but one loop as "removed", and test the machine. If it hashes stably (but slowly) for a few minutes, then try enabling another loop, and another, and another, until you find the one that causes problems. Mark that one loop as removed and then go through the rest. After you've finished identifying the fully-functional loops, you can try enabling one ASIC at a time within the bad loop (make sure to mark the other ASICs as disabled if they're not enabled; only mark an ASIC as removed if you're doing that to all three within one loop).
While the vast majority of SP30s we've received have worked fine, here at
http://toom.im we've had quite a few SP30s with problems of some sort or another. We've been able to get almost all of them hashing at 4.0-4.4 TH/s by identifying the problematic ASICs and loops and disabling them.
