Quote from: soy on May 09, 2015, 07:59:00 AM

Quote from: tbolt on May 06, 2015, 04:03:42 PM

You said:

Falling hashrate problem with a C1. It has been running at intentionally lower frequency to baby it. Should be running at 960GH/s@243.5M and after a cold start it does but drops to 850GH/s after a few hours. Up last night I restarted due to 850GH/s hashrate.

If this isn't it then it's an ASIC that heats and accumulates errors (an internal board) but even when the hashboard isn't drawing much current while the other three are, there are no x's in any chain.
--------------------------------------------------------------------------------------------------------------------------------------------

Let it run at the lower 850GH/s hashrate for a day or so, you should see X's appear on one of the chains..

Just to rule out other possible causes:
Have you swapped Power Supplies with a different (working) C1?
Have you swapped the Pump/radiator/cooling setup with a working C1?
Ambient temperature?

More than likely it's a cooling problem if it happens after it has ran for several hours IMO

I had a similar problem, at stock settings - 250M/0760 volts (hash rate should be 1008 GH/s, would drop to ~930 GH/s)
to correct this, I had to replace the cooling block used on chain #2

I now run both of mine at 200M /0675 Volts - gives me 805 GH/s each
-due to heat concerns. They are both stable now having run for 29 days
without touching them

I thought it was a PCIE connection problem and shutting down, adjusting the PCIE, then restarting fixed it for a few days. Today a power supply on that machine died. I replaced it and am hashing okay. Time will tell. It was a moderately warm day in the mid-80's and the power supply fan had failed.

So you were able to get a 850 or so to hash normally with just pcie connection? Or was it normal before switching power supply?