Quote from: dlasher on July 24, 2014, 07:30:54 AM

Quote from: TwoPints on July 23, 2014, 11:55:28 PM

Quote from: dlasher on July 23, 2014, 03:38:44 PM

Quick power #'s, measured with my best unit.. and the only one that will hit 500GH.

Corsair TX850 80plus bronze PSU - single S3:
218 mhz -- 450 GH -- 346 watt at the wall
225 mhz -- 480 GH -- 370 watt at the wall
237 mhz -- 500 GH -- 394 watt at the wall

I was a bit curious myself and tested one of my batch one units, but I'm getting different power numbers at the wall. See below:

218 mhz -- 440 GH -- 360 watt at the wall
225 mhz -- 387 GH -- 348 watt at the wall
237 mhz -- 408 GH -- 360 watt at the wall
250 mgh -- 424 GH -- 345 watt at the wall

I'm using a Corsair HX650 for each unit and testing using a Rosewill RHSP-13001. I've only tested one S3 thus far but there appears to be a power issue, or it's just not liking anything outside of stock frequency. I haven't flashed the firmware yet but am more concerned that I'm not pushing the same power to the unit at those higher frequencies. Any thoughts?

So in the apology post that Bitmain posted, ( https://bitcointalk.org/index.php?topic=671189.msg7832797#msg7832797 ) they effectively indicated a bad batch of DC-DC and people weren't going to get the speeds they wanted.. hence the refund/credit.

I suspect they've set all S3's to 218 out of the box, and knowing that most of them won't be able to run over that point. I have (1) of (10) that can run over the stock.. the rest just start X'ing out ASIC's and never go any better.. they're actually faster are 218 than at 225/237/250/etc.

(I know a couple of -really- good board-level guys who could swap-out DC-DC supplies if I had any idea what to replace the faulty ones with)

As far as I know, there are no pin to pin replacement for the 53355 with same or higher amp in the same voltage values.
I already checked for overvolting.
Best bet would be to replace it with another batch of 53355, 3$ each, 50$ for each S3, and not sure it will solve anything.
for low cost fix, I'd try a slight over voltage by replacing the divider resistor. Going up to 0.8v could help.