Hacking the S7 - improving efficiency through minor hardware manipulation

[bbOOmm]

I have been loosely following this topic and thought of this...

All this work, hacking, specific hardware, coding etc .... wouldn't it be easier to literally bypass the whole regulator circuit and supply the chains with a dialed down voltage directly from the power supply? I've been able to get DPS-1200FB power supplies to operate in the 10.5VDC to 11VDC area. There has to be some large solder traces that once the green epoxy is cleaned off, can become a solder point for injecting voltage -after- the regulator circuit.

I did something similar when the connectors for the Avalon miners -- way back when --- roasted the connectors and burnt the boards - I soldered directly to the boards to get them mining again.

Just an idea, I have not looked at the S7 boards to see if it actually can be done space/location wise - the only times I have looked at them were to clean and verify nothing is getting cooked. But with the S7's becoming un-profitable in WI because of electrical rates, I just might take one out of production and play with it.

Unless I find a hashboard or a whole S7 I can play with...

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[sidehack]

10.5V is somewhere between stock and overvolt for the 135-chip miner. Not helpful at all.

I'm not sure I'd describe plugging a ribbon cable into 6 pinholes and clicking "flash" as more difficult than pulling boards and scraping mask and soldering into heavy copper planes.

The good thing about a firmware hack is it frontweights all the work. You spend a day figuring it all out, and then you only need five minutes per machine to make the change instead of spending half a day figuring it all out and then an hour per machine making the change.

Undervolting from the PSU would work on 54-chip boards that don't have a built-in regulator.

[bbOOmm]

As I said, I was loosely following this topic - not reading every little tidbit (think speed reading) ... so my understanding of what you are trying to achieve is probably a wee off. It just seemed like a lot of reverse engineering and experimenting to come to the result of having control over the voltage regulator, not to mention the purchase of an interface to get that access.. hence my comment of bypassing the regulator altogether. I'm sorry if that was of any offense or sounding abit ...derrrr

So its simply undervolting the chip chains to obtain a more efficient Hash/watt ratio? No cgminer tweaks? No bitmain controller tweaks?, just the PIC tweak to undervolt.

If anyone gets bored ... could you make a posting with the step by step how to - minus the theory, whys and results for each step. That page 4 posting is very informative, then reading around the whole topic to gather other tidbits;  for some people, that may seem a little too much info and become discouraged to even try because it seems too complicated and technical. I can understand it, but putting myself in someone else's shoes, some of the screwdriver and duct tape wizards out there just may have a hard time grasping the concept, let alone have the patience to read all the details.

you know, a simple summary,

1) plug in miner
2) plug in PICkit
3) download file xyz
4) press flash
5) reboot

Kind of instructions post for the modifications. Maybe stickied to the first page....

[sidehack]

Well, it's a lot of work for one person to do the reverse-engineering. That's why I posted everything including the new code, so you don't have to "reinvent the wheel". I also already had a PIC programmer.

Yes, the entire point is to make the regulator adjustable. I am of the opinion that a fixed-volt regulated string is the worst overall topology. It does still have an efficiency gain over low-volt VRMs but none of the modularity and it's less efficient than an unregulated string so what's the point anyways, just an excuse for the manufacturer to reduce chip counts and save money.
However, an adjustable regulated string is, my opinion, the overall best topology. It's the most efficient and cheapest means of still having adjustable core voltages, which being able to lower core voltages over time can substantially extend the viable life of a miner. Amazing how you can take a thing from "those greedy bastards" to "wow this is actually pretty nice" with just the one little change.

And if someone else wants to make a simple and boring step-by-step with none of the reason why you're doing what you're doing or why it's actually a good idea, go for it. People stopped asking me for help with their homework ages ago because they figured out I'd actually help them learn how to do their own homework instead of do it for 'em. Course I'm also the guy who is disappointed by people who drive cars and don't understand their basic concepts.

[in2tactics]

..... Course I'm also the guy who is disappointed by people who drive cars and don't understand their basic concepts.

That last bit made me chuckle.

[bbOOmm]

Has anyone tried this with the regular ol S7 - the later models with the voltage regulation?

I just took my S7's out of the rack for a cleaning, and while they are out, I'm thinking of doing this mod.

However, I'm not sure if this mod is an S7LN only thing. I have S7 Batch 9's and Batch 11's; is there anything different in comparison to the S7LN's other than the control board firmware and one extra hashboard?

[RichBC]

Has anyone tried this with the regular ol S7 - the later models with the voltage regulation?

I just took my S7's out of the rack for a cleaning, and while they are out, I'm thinking of doing this mod.

However, I'm not sure if this mod is an S7LN only thing. I have S7 Batch 9's and Batch 11's; is there anything different in comparison to the S7LN's other than the control board firmware and one extra hashboard?

Mod is equally valid for any of the later 135 chip S7 fitted with Buck Converter.


Rich

[IITravel01]

I did it to my regular S7 and it worked fine, but you'll have to find which level of voltage will work with each board.  I had to use 3 different volt. settings for each of the 3 boards in my S7, to get the lowest effective setting.  Was pretty easy to set up.  Only problem I had was many of the holes were filled with solder, but with some experimentation I found that you could still program by firmly pushing the contacts to the soldered holes.

[sidehack]

I did it to about half a dozen S7 (and resold most or all); my experience is pretty much the same as the above poster. The only difference between S7 and S7LN boards is heatsink size.

[bbOOmm]

Awesome. I'll hack em tonight.

Thanks

[Entropize]

I can testify, I've got on of Sidehack's modded 135 chip S7s and it's been humming away at over ~4.25Th/s much lower than stock voltage quite happily.

[bitgameSolo]

I see in the hex files there is  "S7LN_PIC_FIRMWARE.hex" .... the original unmodified firmware for S7LN. Does anyone know how to get the 135 chip S7 (non-LN) version of the original unmodified firmware? I thought I read somewhere when dealing with firmware to back up my current firmware but wasn't sure how ... thought there might be one posted somewhere.

[sidehack]

I've got a copy of that also.

[HagssFIN]

I used one these hex files with PICkit3 for undervolting and underclocking a S7, batch 9  and everything went smooth.
I sold that miner but I'm going to do the same thing again soon to a S7 when the S9 arrives and I rearrange my miners and PSUs.
Here is my setup:

Antminer S7, 640/670mV,  4.223Th/s (60 min avg), 625 Mhz

Power supply: Enermax Revolution 87+ 1000W
Voltage: 227 VAC
Current: 4,7 A

Power (at wall): 1066,9 W

[fanatic26]

For those looking to mass mod without having to experiment with every single board to find the most stable number I have done some testing.

Running later batch S7s at 660/690 with frequency at 600 they are doing on average 960w @ 3.95TH
I also removed the back fan and flashed the S7-F1 firmware to save even more power. Temps are better with 1 fan modded version than a stock version at my location.

[sidehack]

Your error rate is higher than I'd shoot for, but 960W/4TH is a pretty good setting. I've set up several in that neighborhood.

Cool to see this effort still in use. Been a couple months since I plugged the tip jar (1CoLDs7XNi8ehyFnGWicUhgBGb7Kw42Ugi) so I'll do that again now.

[fanatic26]

Yea that probably wasnt the best unit to show off with. Most are more like this one as far as the error rate goes

[bitgameSolo]

I used one these hex files with PICkit3 for undervolting and underclocking a S7, batch 9  and everything went smooth.
I sold that miner but I'm going to do the same thing again soon to a S7 when the S9 arrives and I rearrange my miners and PSUs.
Here is my setup:

Antminer S7, 640/670mV,  4.223Th/s (60 min avg), 625 Mhz

Power supply: Enermax Revolution 87+ 1000W
Voltage: 227 VAC
Current: 4,7 A

Power (at wall): 1066,9 W

So that is 1067W/4223GH. Or 0.252w/GH. You obviously lowered the watt draw, but I'm confused as to whether you are running more efficient as s7 is rated at .25J/GH, right?

[HagssFIN]

I used one these hex files with PICkit3 for undervolting and underclocking a S7, batch 9  and everything went smooth.
I sold that miner but I'm going to do the same thing again soon to a S7 when the S9 arrives and I rearrange my miners and PSUs.
Here is my setup:

Antminer S7, 640/670mV,  4.223Th/s (60 min avg), 625 Mhz

Power supply: Enermax Revolution 87+ 1000W
Voltage: 227 VAC
Current: 4,7 A

Power (at wall): 1066,9 W

So that is 1067W/4223GH. Or 0.252w/GH. You obviously lowered the watt draw, but I'm confused as to whether you are running more efficient as s7 is rated at .25J/GH, right?

You have to take the PSU efficiency in account.
The consumption in 12VDC side is maybe something like 0.88x1067W =938.96W (I used 0.88, since it is 87+ efficiency PSU with almost 100% load)
And the efficiency for S7 is then about 0.222.. J/GH.

The number Bitmain gives for the miner efficiency doesn't take the PSU into account (power at wall -efficiency).

I'm getting the most hash out with the Enermax PSU by using these settings.
With 650Mhz frequency the load is too much for this PSU and it occassionally turns off.

[aarons6]

I used one these hex files with PICkit3 for undervolting and underclocking a S7, batch 9  and everything went smooth.
I sold that miner but I'm going to do the same thing again soon to a S7 when the S9 arrives and I rearrange my miners and PSUs.
Here is my setup:

Antminer S7, 640/670mV,  4.223Th/s (60 min avg), 625 Mhz

Power supply: Enermax Revolution 87+ 1000W
Voltage: 227 VAC
Current: 4,7 A

Power (at wall): 1066,9 W

So that is 1067W/4223GH. Or 0.252w/GH. You obviously lowered the watt draw, but I'm confused as to whether you are running more efficient as s7 is rated at .25J/GH, right?

the s7 is rated at .25j/gh but it realistically is around .31-.33j/gh
even worse if you are on 110v