What do you want for it?

Groovy. I had previously put in a sample request to Molex for what I believe should be the part (based on dimensions and CAD diagrams) and an information request to FCI for data on the power-supply-side connector. Hopefully they get back to me as soon as business starts up for the week. As soon as I get a final board design ready I'll see about putting up some basic dimensional layouts for screw holes and whatnot, in case some of you guys want to do a bit of groundwork on case designs. I'm definitely interested in seeing what folks come up with.

Yeah, me too. There's been a lot more interest than I expected, especially for bulk. Hopefully Cheshyr hears good news from his supply house about the edge connector I'm having trouble matching/locating. Hope to hear back from manufacturer CSRs soon.

You double-checked your batch file for accurate pool and port info?

Have you tried manually hitting "Switch server"? Sometimes mine don't pick back up without telling them to.

The "R" fuse is 8A rated. The blue-board Blades came stock with 10A fuses, at least all the ones I've seen. I'd replace with a 10A SMD fuse, I believe package size 2410. It shouldn't take much forum searching to find several relevant links to parts suppliers for a replacement.

Have you tested the fuse for continuity? Use an ohm meter to read out, or a continuity tester, heck even a low-voltage battery and LED. It's riskier but you can also short around the fuse with a paperclip or something temporarily to see if that powers it up.

https://bitcointalk.org/index.php?topic=352658.msg4050783#msg4050783


If you run each adapter off a separate molex line (as in, not four connectors on the same wire) it might work. These can draw around 12-13A from each PCIe without blinking so you'd want them on separate lines or your wires will melt. Also make sure your 450W PSU is rated for at least 25A minimum - 30A is better, so you're not running everything at capacity. If it's a somewhat old supply, it's probably got the 12V and 5V co-regulated so putting any sort of load on the 5V rail will probably help keep 12V voltages high (closer to calibrated 12V at least) which will help reduce current draw for the same power draw.
And then make sure everything's seated tight so you don't smoke out the connector pins themselves.

The pin headers on the board are for linking multiple supplies; each has an input and an output so you can either chain them (where one supply turns on the next, which turns on the next, and so forth) or run them in master/slave (where one turns them all on) and both headers tie the current share lines. The only thing you'd need to do for hotswap in parallel is make sure the ground and 12V outputs are tied into the same bus.

I wonder if I shouldn't put on a fan speed override with a linkable header so the master supply could control the speed of all linked supplies, or it could be linked to an external temp sensor driver that monitors the temperature of the exhaust air? Do people think this is useful enough to implement?

The supplies I'm testing with were built for the Dell PE2950, which is a 2U. But other than that, yeah spot on. The local shop I used to work for did a fair bit with servers like these, and one of my best friends is making a living as an IT guy dealing mostly with older equipment that's not bleeding-edge but still pretty gosh darn solid.

As for not needing 80Plus certification, these supplies have them anyway, and I'm impressed with the outcome. http://www.plugloadsolutions.com/psu_reports/DELL%20INC_Z750P-00_750W_SO-81_80+_Report.pdf

Also keep in mind these can be used as additional 12V rails in GPU farms by using the chain feature off an ATX master supply, not just for standalone miners.

Two PSU for redundancy? One of these supplies should handle two or three blades itself at stock clock, if I'm remembering the power specs right. That would be a pretty sexy setup though.

Gotcha. I'll see about probably widening the board slightly and adding screw holes at the corners; these can double to hold a plastic baseboard under it for insulation in standalone applications, and for mounting to frames in your type of application.

If you refresh during a hang, do the chips still read O or are some of them X'd?

Whereabouts and what for exactly?

You're probably limited by internet speed/latency. Try a local stratum proxy running on a computer inside your network and see if it picks up.

I've been playing around with hacking server supplies since probably June, first for GPU and now for standalone. Decided it would be a better way to go to make a pluggable interface board than make all the changes internal to the PSU. Faster, easier and interchangable/replaceable.

What I'm working with has pins and blades, not an edge connector, but I'll probably start looking into making for the HP 850/1000 that everyone seems to love from their Blade backplanes.


I'm guessing you're using a 12V relay to kick the supply on from external source?

What's the voltage on the 3.3V lines read? Is it steady at 3.3V, or does it sag a bit - especially during a "hang"?

First "complete" prototype finished and undergoing testing; as soon as a reliable source of parts can be found I'll start on actual production. If anyone's got an "in" with Molex or FCI I wouldn't mind a bit of assistance tracking down both parts and information.








This board is designed to mate with a Dell Z750P power supply from a PowerEdge 2950; said supplies can be found fairly readily on eBay in various conditions for as low as $12. They are rated to provide 62A at 12V at 90% efficiency. This interface board provides
 - Screw terminals for +12V and GND so you only hook up what cables you need.
 - Additional output capacitance for voltage ripple and burst current buffering
 - Manual fan speed control (the stock full speed is quite loud)
 - Auto-powerup which can be triggered by an external signal as low as 3V, disablable by a toggle switch
 - Manual powerup from a toggle switch. Because toggle switches are legit.
 - In-signal and Out-signal headers which allow chaining, so one supply can turn on multiple others
 - Current share feature which should allow multiple supplies to cross-regulate and evenly distribute high power loads in parallel


I've had one of these supplies running a pair of full-overclocked Cubes for a few weeks with zero issues. These supplies, equipped with these boards, should work beautifully for standalone miners at reduced cost for comparable ATX supplies (similar power and efficiency) and without requiring paperclips or additional wire management. Output regulation should also be better than a standard ATX.

They'll also work as additional 12V rails controlled by ATX supplies; the auto-powerup was originally designed to fire up the supply as additional power for a GPU rig.

The Z750P uses a fairly common interface style and pinout; I don't have a complete list of other supplies this board would work for but there should be several.

I don't have an estimated price tag yet, probably in the neighborhood of $30 to $40 - a lot of that is going to depend on the cost of parts. All manufacture will be done by American people in America, which adds to the cost a bit but one of the tenets of my business is to never for any reason outsource jobs that can be done domestically.

Got about five kits left ready to go to anyone that wants 'em.

In the next day or two I should have prototype information available for an interface board designed to break out server supplies for use with miners; these can typically be found for much cheaper than an equivalent output/efficiency ATX supply and usually exhibit better regulation. Screw terminals so you only use what wires you want, and additional output filtering. They're also designed to be run in parallel with load sharing and daisy-chain for automatic power-on in groups.



If enough people want it, I'll look into adding a trimmer to tweak output voltages.


Been watching this thread; series power dropping chips (if it can be done reliably) is such a darn cool idea and if someone ends up making these boards affordably (and chips are available for not a bajillion dollars) I'll definitely be in the market. Good work, guys.

Nuts, knew I should have pushed that payment just a little bit sooner... second on the list for tomorrow's shipping. Oh well, still pretty quick turnaround. Thanks, guys.