underperforming S2

[mdude77]

Hi all.  I have a gen 4 S2 that seems to be underperforming.  I've had it running for about 5 days now.  It's averaging about 920 or less GH/s.  All 10 chains are showing up, and for a while there were no Xs.  Now there's one in chain 1. 

I thought the 1000w PSU was the cause, so I swapped it with a 1300w gold PSU.  No change.  I've reseated all the chains, twice.  No change.

One of the chains isn't reporting a temp, so I'm thinking of yanking it and see if my hash rate stays the same. 

I'm attempting to reach out to Bitmain for help.

Any other suggestions?

Thanks.

M

[alexrossi]

Have you already tried an hard reset, like on the s1? (Maybe it was the first thing that you have tried to do, so you haven't even writed it)

[mdude77]

Have you already tried an hard reset, like on the s1? (Maybe it was the first thing that you have tried to do, so you haven't even writed it)

power off/power on?

Yes, multiple times.

M

[alexrossi]

Have you already tried an hard reset, like on the s1? (Maybe it was the first thing that you have tried to do, so you haven't even writed it)

power off/power on?

Yes, multiple times.

M

No, a software reset (return to default settings)

[mdude77]

Have you already tried an hard reset, like on the s1? (Maybe it was the first thing that you have tried to do, so you haven't even writed it)

power off/power on?

Yes, multiple times.

M

No, a software reset (return to default settings)

Haven't tried that yet.  Is there a reset button somewhere?

Also, oddly enough, it certainly appears as if this problem only happens with p2pool.  I've tried different nodes (including local), and different difficulties, and the result is the same.  Yet if I point it at Eligius, I get the expected hashrate. 

To be clear, it's not just p2pool reporting it low, the S2 itself does, on the web interface and on the LCD.

M

[GaryL]

You should contact the seller first.

[jimrome]

Given that you're overall hashrate isn't terrible, maybe it's just a flaky board? The trick would be to figure out which one.

A couple of ideas:
- check cgminer debug log (or 'kernel log' as it's referred to in the OpenWRT UI) and see if a particular chain is reporting more errors than others. If you find a particular chain is having issues investigate why - e.g. is it getting too hot? You can also see this if you log into the shell and watch the cgminer output (screen -r). It may look to you like gibberish to start with.
- Pull all cards aside from one, and then begin systematically adding each card back and verifying that the overall system is performing as expected (tedious)

FYI: The temperature reported for each card is the output of a single IC on each board. I forget the exact part, but it's the same as is used on the S1. If the board is not reporting temp it's possible that this IC is damaged, missing, or has bad solder joint(s).