I wasn't sure if I had explicitly explained it here or not, so if I haven't then you have no need to apologize.

Anyone ever that has a problem with the fan speed, read https://bitcointalk.org/index.php?topic=379677.msg5721102#msg5721102

First thing to try - make sure it's set for internal instead of external fan speed control. If it is set for external, set it to internal and try again. If it still doesn't work, set it to external and ground the FAN pin. If it still doesn't work, I have no idea.

If it doesn't work on internal but works on grounded external, short around the 393 resistor on the backside of the board and try the knob again (on internal). If that works, either permanently short around that resistor or tie a wire from the rightmost pin on the knob to ground.

The other option if it works on external, is rig up an external pot between the 3.3V and GND pins on the header, tap on FAN,and adjust from there.



For the record, this is not a problem with the board. It's a change in internal design spec on a different variant of the power supply than I had to test with. The half-dozen supplies I used all worked, but there exist other variants that, for some reason, use a different voltage standard for fan control. It's not a problem if you have a closed-loop active controller, but that's not what we have.

And since this is the third time I've answered this question today, and at least the eighth time I've answered this question in the last week, I'm gonna start directing people here if they ever mention the word "fan speed" to me in any communications.

Unless you ever need to maintain it.

A semi-permanent solution I'd recommend is cut a piece of plastic or something and mount it using the screw holes on the board. Won't come off on its own but easy to remove if you need to.

Yes, if the bottom side hits metal it could risk shorting. I'd recommend putting a rubber mat, tupperware lid, or junkmail underneath the board just in case.

10 Blades, 5 two-blade (standard) AntMiner S1 units.

I know when the servers fire up they run at full fan everything ever for a few seconds, until stuff is initialized and it throttles them all down to manageable levels. Two PSUs and a couple other 2U fans and those servers are effing LOUD.

Also, a consideration I'd like opinions on. The DPS-2000BB does not have internal fans, so external fans need to be provided. I'm going to put a speed controller with fan headers on the board, probably for a 4-wire fan. Does anyone have a compelling reason why I should design for a 2/3-wire fan instead?

I just took one off my desk that's been running in my room since probably November. It does definitely seem quieter in here, but not enough that I really care. Maybe that's what happens when you work around loud fans every day for three years though. When the fans are turned down they're not too bad. By my standards. I'd rather have stuff that works really well than is comfortable.

I don't have any DPS-800 boards for sale, we're still prototyping. All we have right now are the D750 boards. Load-balancing is pretty easy once you understand what's involved. Load-balancing and master on/off can be done with two power wires and two signal wires.

https://bitcointalk.org/index.php?topic=503423.0

External fan, the actual pot resistance doesn't matter a whole lot. I'd probably use a 10K. What really matters is a wiper voltage range that includes 0-1.8 or so.

Yes, GekkoScience is my business. Hence why all the links are to stuff on gekkoscience.com

Also 3 AntMiners at stock clock would require, if the measurements I did a while ago were accurate, about 960W. If you have a 1000W supply that you trust (like perhaps a DPS-800GBA on 220V power) or greater, it's probably possible. Two of these D750 boards load-balanced would supply 4 Ants at stock or 3 Ants overclocked without any issue. Might do 4 Ants overclocked, I don't recommend it but it has been done.

Gotcha. They do also have different power outputs and stuff from different models, but I haven't actually messed with them. It'd probably not be too difficult to disable/hack the 12V line if necessary, but then again "difficult" is an intensely subjective qualifier.

Nifty. I don't have any picoPSU running around but a future project I have in mind will incorporate one running off probably a DPS-800 supply.

We're working on DPS-2000BB breakout boards now, I hope to have a final schematic tomorrow and start on the PCB design. Should be interesting. Gonna build about a 3KW adjustable dummy load to stress-test them; the board should be rated for at least 200A without issue. It'll also incorporate a PWM fan speed controller with internal and external adjustment.

We're also working on a plug-and-go board/cable kit that'll allow you to load-balance and simultaneously control 3 boards at a time. It'll be good for the current D750 boards, and the DPS-800 and DPS-2000 boards we'll be releasing soon. The ability to turn all supplies on and off as a unit, or disable specific supplies in case of problems. The ability to daisy-chain controlboards for more than 3 supplies at a time. Status LEDs for PSU standby power, PSU-on and 12V present on the bus. And unified fan speed control. Should be pretty nifty, and solve a lot of questions people have been asking about parallel/load-balance. I'm all for people learning how to do things themselves, but some folks just can't, or won't, and then if they got an extra ten bucks or whatever maybe they'll just use the it's-already-done-for-you kit.

Every supply I tested, the voltage range output by the knob worked. However, HOWEVER... someone at one of Dell's various Chinese outsource design houses decided it would be a good idea to make some with a different reference range for fan speed. I guess it doesn't matter a whole lot if you have a closed-loop regulation system, but these boards don't do that.
If you have the skills to do so, shorting around the 393 resistor on the bottom side of the board should give you the range to control the fan speed on those supplies. This problem wasn't known until recently, so a true fix won't be applied until the V0.6 boards.
The other option is to wire a potentiometer between 3.3V and GND pins on the header, tap on the FAN pin, and set the board to use external fan control.

You didn't get a PM response because you PM'd at 1AM my time zone. Did you email sales@gekkoscience as specified in the initial post instructions?

As for connecting to load-balance, yes. I wouldn't use the spraypaint to connect terminals though, but that's just me being sarcastic. Your orange line is tying the SHR pins together, which the supplies use to cross-regulate and ensure an equal distribution of current. To turn them on simultaneously, you need to use the EON signals also.
On mine I have one master supply, whose POK is wired to the other supplies' EON lines. When the master supply turns on or off, the POK line goes high or low respectively, which kicks on the other supplies at the same time.

You shouldn't really need to connect all the terminals together on every board, as they're all electrically connected already. Unless your load is very very unevenly distributed across the boards. I have 10 S1 blades pulling from 3 PSU boards, so 4 on one and 3 on the other two. Pretty evenly distributed, but the two 3-blade boards push a little current to the 4-blade board. I have 3 16AWG 9" leads (in a single spade, like the standard cables) running between the first screw on adjacent boards to link them exactly as you have pictured.



As for these being noisy, I've slept beside case fans for so long that it's hard for me to sleep in a quiet room anymore. A few months ago a supply gave out on me and powered down two Cubes; I woke up almost instantly (the fans were still spinning under inertia) because the lack of fan noise tripped alarms in my subconscious. When the fans are turned low, they're not loud by my standards but my standards are probably skewed.

Sweet! I estimated a pair of 400MHz Ants would be basically 99% capacity for the supply, so 2 weeks uptime at that load is pretty dern sexy. The only one of these supplies that's laid over on me ran a pair of custom-overclocked Cubes for a week basically with the fan disabled.



These will run 100-240VAC
Email sales@gekkoscience for pricing/shipping estimates. 3 in parallel to power 5 Ants works, I'm doing it right now.
The PSUs don't get terribly hot; if they're too warm just turn the fan up. They have internal fans and the board has a speed adjust knob.

Good to hear, sir. Thanks, until my minions are fully trained on acceptable standards I've been going over every board for mechanical, functional and cosmetic to make sure everything was top-notch, so I like hearing what you just said.

Also I currently have 5 AntMiner S1 on 400MHz overclock, load-balanced across 3 of these boards with zero issues. Been running about five hours so far. So that's good.

Anything is possible, sure, but none of what you just said is recommended. The boards' 3.3V and 5V lines are auxilary, rated for 2A, so if you can guarantee your ATX supply will pull less than 2A you might not smoke something. The aux power lines are there to power external controllers for handling multiple supplies, or things like Raspberry PI that are packaged with some miners.

The board is built to work with one power supply. There are probably ways to use only 1 breakout board for two supplies, but that defeats the purpose of the breakout board, probably won't be terribly safe or terribly reliable, and soldering stuff to the board will probably void any implied or actual warranties.

Would you be able to? I think that questions your capabilities as a hardware assembler and I can't answer that for you.
But anyways... If the risers only take in 12V from the molex, and the cards you mentioned pull the power you mentioned combined through the 6/8-pin and risers, then yes the DPS-1520 should be able to power your 4 GPUs and their attached risers. Your ATX would then only need to source power for the other GPU/riser (~300W?) and motherboard (~200W?) so a 500/600 ought be sufficient. Probably?

I'd rather run wires for each connector instead of sharing. It can be wired with two connectors sharing the same wire, but its reliability depends on the length and gauge of the home run because you'll be pulling the full current of both connectors through it. The more current through a wire, the more power dissipation in the wire. That means the wire warms up and, if it's way under spec, could melt or burn something. Power dissipation in the wire is also a result of voltage drop in the wire, which means less voltage getting to the load, which means a higher current required to power the load fully, which further increases the strain on your wires. If it's calculated out properly you shouldn't have any problems, but in general the more copper the better (at least as far as is practical with weight/price, like for most of what you're doing 000AWG won't do you any better than, say, 14AWG).

Depending on the strength of your desktop supply, it should. Powered risers you should allow at least 75W of 12V per riser, and at least 300W of 12V for your other GPU. Depending on your board/CPU, you'll want 100-200W for that. Looking at getting at least 800W desktop supply to run all that.

If anyone, ever, anyone at all, has any actual experience building GPU rigs with riser cards, feel free to chime in. The most I've done is 3 GPUs direct on a board, with an ATX giving 35A of 12V and a 500W server supply doing the rest. The only advice I can give regarding high-end crap is somewhere between theory and conjecture. Never used risers, never used an ATX supply over 500W, never used more than 3 GPUs, never used a DPS-1520.

Preemptive disclaimer that I don't work with GPUs a lot.

But I would imagine the 300W and 280W from your cards, part of that is coming from the risers. If you don't plug the risers into a heavy external supply but run them off your ATX, I'd allot at least 6A of 12V per riser. If the 300W/280W is straight external, they should all run off the DPS-1520 without issue. If that includes the socket power (from risers in this case), you could power the risers off the DPS-1520 and still only be at 80% capacity.

If, then, you ran your 6950 and motherboard off the ATX supply, I'd recommend probably at least a 500W unit. Maybe more depending on what processor/motherboard you're running, and what overhead you want to allow for.

What you could do, and an idea I've toyed around with but haven't tested yet, is actually get two server supplies in parallel load-balanced (I don't know enough about that particular model to know if they current-share or not, but I think most do) and get a picoPSU running off the 12V bus for your motherboard. Those things aren't terribly expensive, and run around 96% efficient. If you isolate your riser power from the motherboard power (either by using the recommended USB-style risers or cutting the 12V lines to the ribbon) you shouldn't overload anything on the picoPSU by trying to pull GPU current through it, and anything else requiring 12V (like GPU, or processor VRMs) would pull straight from your ~3KW 12V source.