I just did the math. Frequency times chip count times core count equals hashrate, for the numbers given for an S7.

BM1380 had 8, 1382 had 64 I think, BM1384 55, BM1385 50.

...and then requiring about a 300A multiphase buck at probably 85% efficiency, which is pretty generally a bad idea.

Also, I've settled on terms for the group buy so that's live now.

As of right now, I can get an S7LN shipped to my shop for about 0.51BTC

If I ask 0.59BTC all-in for an S7LN clocked at 620mV cold and 450MHz, for 2TH off about 415W, with fans preset to 20% expecting board temps about 50C and very quiet operation, tested for a full day for stability and the price includes shipping from me within the US, who is in?

If that sounds agreeable, send 0.59BTC to 1CoLDs7XNi8ehyFnGWicUhgBGb7Kw42Ugi and a message signed with that address to me in PM. I'll also need your shipping address. When we get up to about 6 units paid I'll place an order and get 'em sent.

If you can solder, replace the caps. I don't know how many hundred motherboards I've brought back to life by replacing blown caps.

The problem with updating the last setpoint is, you can't change it without reflashing the whole PIC firmware again. Unless you could talk to it via the controller's TX line, but if you can do that you might as well just write a firmware to set the voltage wherever you want via controller software. Which is probably what Bitmain's firmware already does, we just don't know the commands to make it do what we want. And I have probably already put more time on firmware than I should have, but it's the most fun I've had at work in months. Manufacturing is super boring, but it's also super necessary if I want to not go bankrupt, so I probably won't have more time until I get caught up on building stuff. Unless I get a bunch of sales on PSU boards right quick, in which case maybe a day of additional firmware dev would be a good celebration.

Anyone looking for a good PSU to run an S7 or S9 off 208/240?

https://bitcointalk.org/index.php?topic=1493601.msg15180315#msg15180315

Please note the responses to when you asked the same question in this thread yesterday.

Based on what the folks in this thread have said, it looks like the PIC never updates the DPOT's setpoint. If it's a resistor going out doing that, it'd almost have to be one of the 4.7K pullup resistors on the I2C lines.

I would guess it's not a resistor in the VRM circuit, given that it appears the DPOT is starting to midpoint and the buck is operating properly. The PIC's VDD actually comes straight off the 3.3V line on the 18-cable to the controller, so if it was a volt issue toasting the PIC it'd also affect the DPOT and controller board.

One problem with having a hot and cold setpoint are, since the hot setpoint is only delivered when the miner is first powered up, it's entirely possible that simply restarting cgminer after a board drops out will actually cripple the whole machine. It really requires a power-cycle - more specifically, it requires cutting 3.3V to the hashboards which would require either power-cycling the controller or some external hardware.

Since the micro listens on the TX line, I could have it just check in for traffic and if it detects there's no hashing going on (so, cgminer was killed) it resets back to hot setpoint to be ready to restart mining. I'll have to look into exactly what traffic gets sent when cgminer is still operating even though the board is down to know how to detect that condition, and I don't really have time for a while.
Possibly the code could increment the cold setpoint every time mining fails and is restarted. One problem with that is you couldn't optimize per-board since both boards would detect cgminer restarting and both increment even if only one needed it. Also, unless it was saved to EEPROM, the new setpoint would be lost every power-cycle. If it was kept, without a means of resetting back to defaults, over time the setpoint will drift higher and higher due to internet downtime, manual reboots from software and other issues.

Not really. It was a "hey this works but it's 7PM and I want to go home and eat lunch so I'll leave it on overnight" kind of test, and when I came back in the next day it had dropped out and the lifetime hashrate average was a bit over half expected so I extrapolated about how long it ran before stopping while I was not there to observe it.

I think the problem with the 610mV profile is probably balance. By the BM1385 datasheet, the chips should run 425MHz at 600mV. However, since the voltage is dropped per node according to the current use at that node, there is no perfect balance. If one node is dropping even 2% lower than the average 610mV setpoint, it's gone down to 590mV which I've found is in a range 28nm ASICs don't particularly like. The 620mV setpoint gives more leeway in node imbalances at the cost of slightly higher per-unit power use, so for now I'm recommending the 650/620 profile as the best stable bottom clock.

I'm questioning the stability of the 610mV setpoint. My first extended test last week was 610mV 450MHz, and it kicked out after about 8 hours. I ran 610mV 425MHz overnight and it kicked out after about 3 hours. But running 620mV 450MHz ran all day with no issues. The 620mV is about 0.22J/GH versus just under 0.2J/GH for 610 so I wish it was stable but I'm not so sure. Might be 620 is the best we got.

I haven't done any extended tests, but I did determine that the hardware is capable and I have the required data to hit voltages above stock. The full range on the regulator is from about 580mV to 770mV chip-level.

Yes, if you were into that sort of thing. Stock on the S7LN is about 670mV, but I can take it as far as 770 if you want your miner to burst into flames.

Also my S7LN is currently testing at 1.9TH 365W which puts it ever so slightly below 0.2J/GH, at 47C 20% fans.

It looks like my 640/610 profile is just fine for 400MHz, delivering 1.8TH at 340W for an efficiency of 0.189J/GH

I'm testing 425MHz on it now, and it's looking good. If it runs stable all night (I'm at zero errors five minutes into cold voltage), I can say 1.9TH at, according to my meter, 366W for 0.191J/GH. So this S7LN will go below 0.2J/GH machine-level. I was having trouble with the 630/600 profile doing anything right, but I'll check and make sure I just didn't screw up the code.

By the way, those numbers are for fans fixed at 20% (1560RPM); peak temp is 47C and it's as good as silent to me.

Of course, it may be just as easy for someone to just buy one and have it shipped to my shop. I'd still need a shipping label so I could send it on once it was worked up.

I spent the last couple days writing some new PIC firmware for my S7LN (delivered Wednesday 8th) and have been testing it. Right now my machine is running 2.03TH and pulling about 415W off 120V, putting it at an efficiency of right around 0.205J/GH for the machine. With the fans at 30% my board temps are 45 and 47 in a 75F ambient and it's not upsetting my TV watching though the outlet of the miner is only about 8 feet away. I can probably make it more efficient with more testing, and I bet it gets quieter.

I'm working on testing other voltage setpoints and will be putting up some efficiency curves and making the code available to anyone who wants to wrangle his own hardware. It'll require a PIC ISP programming device and accompanying software. There's a discussion thread over in the Hardware forum proper about this.

So I mentioned maybe doing a group buy to bring in some S7 or S7LN, and I'd flash 'em to the desired setpoint, test 'em for about a day and ship them within the US. I already have three people interested to the tune of 5 machines. I'm thinking of gathering coin for set of about 5 at a time plus shipping to my facility, plus about 0.05BTC to do the work and testing. It'd be nice if I could get a shipping label for them as well, but we can work that out. Any import duties would also have to be worked out, which is why I was thinking of keeping orders limited to 5 units.

The current plan is to send $420 worth of BTC to address 1CoLDs7XNi8ehyFnGWicUhgBGb7Kw42Ugi, and PM me with a message signed by the sending address and I also need your mailing address. If you would rather use PayPal or some other payment method, let me know. Machines will be set to 620mV cold operation (630mV if 620 is not stable) and 450MHz for around 420W at 2TH, unless otherwise specified.


-------ORDER QUEUE------

Round 1:

2 - navigatrix shipped
2 - IITravel01 shipped
1 - CrazyGuy shipped
1 - fullzero shipped

Round 2:

1 - ZedZedNova testing
1 - zyzzyva testing
1 - achtung082 testing
1 - -EOS- testing

going to phil:
1 - HaggsFIN testing
1 - philipma1957 testing
1 - gt_addict testing

Well, looks like we got 5 for a group buy. I'll take that over to the right section then.

Glad I'm not the only one thought it was high. My 400A 3-phase run, 100 feet from the pole to the main distribution panel and from there 80 feet to the hosting sub-panels was only $4500 in materials, including 1400 feet of 250kcmil aluminum. Most of the rest was the new main panel plus three breakers at 150 or 200 amps. A simple 60A two-pole subpanel shouldn't have cost nearly a thousand bucks.