OK the S2 now has been running for 16hrs and the (avg) has dropped down to 903gh/s. I've emailed Bitmain about getting a replacement but haven't heard back yet. Has anyone had any experience with Bitmain when it comes to warranty issues, or how supportive they are in resolving these types of issues?
Are you sure all blades working well?
As tzortz said above, are you sure all blades are working well? Do you see green lights flashing on all of them?
You might just have a faulty board or 2. Try by taking them out: take one out, boot up and see if it runs at 900 Gh/s or 800Gh/s. If it runs at 800, then put that board back in and take out another one and try again... that way you can narrow it down to which boards are faulty and send those ones instead of sending the whole machine... that way you can still mine at 800-900 Gh/s while you wait.
I emailed Bitmain about my faulty machine, it took 2 days to reply, but they sent all the necessary details to RMA, with postage at their cost.
Thanks for the advice, I wasn't quite sure what to do but that is a pretty sound solution there. I was fearing that Bitmain would just ignore me and I'll be stuck with a faulty rig.
I'll post some results in a couple of days as it takes a few hours for the hashing speed to start falling.
Test so far was restarting it about 6.5hrs ago and its already fallen down to 958.14(avg).
Sounds like you might only have 1 board that's faulty, just pull them out one by one (obviously power down in-between) and wait till you see it stable at 900Gh/s, then the board that's out is faulty.
Also check the boards carefully, one of mine was missing one of these little yellow pieces from between the chips and it still worked, but wasn't very stable. I just put it back in place and painted the ends with silver conductive paint and the board seems fine now:
I left it running over night and check the speed in the morning, the speed reduced down to about 850(avg).
I've removed a suspicious blade that was running about 15-20 degrees cooler than the others. Its only been running for about 15min so I'll have to wait for the results to come in, but at a glance the speeds is holding at approx 900GH(avg). If it maintains that speed after about 6 hours then I will remove another card and put it into the empty slot to determine if the fault is on the backplane or the blade.
This is an ongoing issue with Bitmain in general. I too was just hit with a failed part, and the turn around on failed product WILL result in serious loss in mining payouts. There is an advantage to going with Bitmain for mining hardware, however due to their support on hardware with issues, you need to factor in as serious losses in revenue .
Yeah I've accepted that I will probably never reach ROI, and its very frustrating/depressing watching your investment go from bad to worse.
