Compared to earlier Wayback snapshot they have removed pics of smaller miners from home. They and the 1.2TH are still there when ya click on 'see the specs' on the rotator for the 2.4TH.

Paid with check here, deposited at Eagle Bank. Nairy a peep from them since and nothing for some time now...

Looks pretty cool. Any chance it can do some basic 'ux stuff as well like the Ant's interface does? Mainly easy backup/update?

Not a peep from them even regarding the hosting they were hawking.

Cool. Wish I had my miner...  'Course I'd like to fly and spit diamonds as well.  So far seems as likely

Doesn't the backplane have a coms chip on it for the GPIO/hash cards coms?

Polycarbonate (Lexan is a registered TM) great choice. Not only good temp before warping but also unlike acrylic it is hard to shatter.

On those mysterious 10k resistors - def a mistake on them. No way in hell are they right. Even from a size standpoint, those would be 2w resistors or more and @12v 10k would dissipate a max of 14mw. And no, no polarity. With resistors the band is just for vision systems on the pick-and-place to know how to verify the number faster. Assuming it uses one that is...

On the PSU switching and PSU in general, is the 12vdc only used to power the hashing cards? If so, ja using the power_OK line is a good idea. Better yet (and cheaper) - how about a lil 5vdc supply for the pi and whatever else needs it and a 1U server PSU for the cards? Leave the Pi on and use the PSU remote on/off to switch it.

For my Ant pharm I use ones from Amazon. $51 for 1,200w HP server psu (runs 2 OC'd s1's pulling 850w per-pair) and @ >95% efficiency they are better and smaller than any PC supply.

Sounds like with better attention to assembly and thermals the AMT/BMch rigs can do fine. The SPI chain thing scare me a bit though. From what I gathered per that SPI coms wiki it doesn't do ring config, just serial chain and at best a star & chain config if all 4 master lines are used. No matter what, all I/O goes through the 1st (master) chip..

Local decoupling caps is but one way for best-practice. Note at least one other major difference:

The bitmine/AMT boards use 12? Vcore supplies (I swear somewhere I have a pic showing 6) that from I can tell are all feeding one very large set of power planes. Unless the Vdd and return planes are incredibly thick there will be large local circulating currents. There will be interaction between the chips ergo the pretty much mandatory need for the larger 6uf local caps. to reduce that problem. The myrid of tiny local 100nf caps. surrounding the A1's take care of the dips & rebound spikes cause by the logic switching. ISa: are the power planes segregated at all?

Now from what little I've seen of it the TechnoBit version only addressed the thermal needs by making it easier to clomp a single large heatsink to the top. But they kept the same idea of the paralleled regulators feeding everything.

Sorry Isa but I gotta say bad idea. For one, if there is a major fault either the whole board goes down if like from a screw shorting things (a bit more care building and testing takes care of that barring something shaking loose in shipping). Or, rather more serious from liability standpoint, because by necessity that very large single source packs a lot of punch if a chip shorts, well we've seen the results of that. Burnt boards with hopes the PSU shuts down before fire.

The new InnoSilicon board addresses those points. They kept the slew of tiny low value caps around the chips and yes have the needed larger caps out at the edges of the sectors leaving access to the chips for the top heatsink.

However. Note 2 things:
1. Power wise the ASICs are actually in sets of 2. Each ASIC pair has its own set of regulator FET's and buck inductorss. Not 12 feeding 8 chips. If a chip goes kerfluey hopefully you just lose the one or at worst the set. Also as you mentioned they may have split up the SPI chain as well Good idea. Again at worst you only loose 2 chips.

2. Those power planes appear to be gold flashed/plated. Between splitting up the supplies and the gold the circulating currents I spoke of are taken care of. Good choice there and not really *that* expensive. Depending on how thick maybe 5-cents per board tops. Electrically silver would be best but with all that aluminum in close proximity can cause corrosion problems unless passivated (even more cost).

3. Goes fuzzy before zooming in much but looking at some of the holes for heatsink screws the board looks pretty thick. Evey with 4 layers too thick for being made of FR4. Tlam or such perhaps?

Given all that attention I'd like to see the contact side of their top sink... Bet it has copper riser plugs pressed into the aluminum.

You can underclock through software. ISAWHIM is more familiar with what range we have. But, won't help with this. We are concerned with the rise/fall times of the switching load - not its overall freq. It is a square wave so the transition times will be the same. If one has boards with the resistors in place of caps the only solution is to remove the resistors and put in caps.

Don't bet on it. At the clock frequencies the ASIC run at those spikes/dips can cause all kinds of havoc if not decoupled at the chip. Methinks that kind of oversimplified thinking is what got BM.ch into trouble in the first place. Power distribution at high switching speed loads is a very localized thing.

Not sure how well the reference boards work but if they do, then yes, just get a bunch and string'em up. Is what the Ant's do. Looking at their boards each is made from 4 identical sectors. Each sector even has it's own Vcore supply.

I assume that BM.ch just wanted a 'clean' design for the 8-chip boards. And blew it royaly.

SMD resistors come in the same package. The ones isa found that begin with R+ are 10k resistors. Those should be caps.

yes we are. Start at https://bitcointalk.org/index.php?topic=569769.msg6754740#msg6754740
they are physically identical packages aside from the numbers on them. Someone screwed up badly there with what reel got loaded into the stuffing machine.

Those are the references I use They also have complete info 2-chip reference board including the gerber files for making a pcb and parts list for it. Whether or not the reference design works... who knows but it's all we have to go by.

In the 2-chip reference design on github the chips themselves are daisy-chained for the SPI coms. Goes in one side and comes out the other. If you pull a chip I'd guess that you just need to place 2 jumpers on the boards pads to pass the data on to the next in line. Again, don't have any hardware here much less the new boards layout/schematic to verify that.

We will have to hear back on whatever isawhim's idea is with the not-responding board. It does seem that some of the local decoupling caps are missing/erroneously changed with resistors.

The traces we were talking about are 2 different things, one being the boards power-planes being shorted by a screw. In that case - or a chip shorting - then the single Vcore regulator they use for each board is going to try and feed all the power it can into the short until it is burned open. If the short is to sturdy to burn open it is going to kill the whole card and possibly also cause the PSU to shut down.

My ruminations are about the A1 chips internal power routing: There are 7 power pads feeding in Vdd: 4 very large ones, 2 smaller ones in 2 corners plus one more very small one. If for whatever reason all the big Vdd pads are not connected from bad soldering or not properly bypassed (missing caps) then it is very possible that connections inside the chip which are still getting power could overload and open up killing the chip. Methinks isawhim is going to try and get around that.

Man that 1st sentence was a long one...
Anywho, at least you got *something* even if it is a paperweight. I also ordered a 520, In my case I only went with that from AMT because the 520 was not advertised as pre-order. It was falsely advertised as 'delivery in 4 weeks or less' implying they were in production...  

I even asked for a DIY when they made the offer. Too bad they didn't follow through as I along with opieum2, ISAWHIM maybe a few others here are ideal folks to get the kits so we can figure out what is wrong with them and come up with fixes. Or - certify design & manufacturing issues caused by their contract manufacturer. Oh well, AMT's loss. And mine  

I wonder how the power internal to the chips is bussed. One can assume that all Vdd pads are tied together at various points, question is, how much do they rely on the main feeds from the pads to be in balance to keep from burning out spots in the internal traces? I would think they can tolerate a local 2x overload at best.

eidt: looking at that that kemet info is great - very good coverage on exactly we are talking about on bypassing

If you have a scope it would be interesting to see what the 'filtered' Vdd feeding each side looks like. Betcha the voltages are different. Ones w/o caps will probably have bigger dips & spike at 2x the clock freq.

And def right on the heatsinks. That is prob #1. My thing on the power comes from the industrial 24x7x365 running mindset. It is sooo easy to do it right the 1st time and be done with it rather than fart around with 'adequate'. Bites ya in the ass every time.

Would be nice to have a schematic of the circuits. The myrid of smaller caps are either across data lines for shaping the data eye or more likely there to knock out very high freq ripple. Is not just the total value of capacitance use but how it is achieved.

A capacitors internal reactance changes with frequency (think crossovers). Large value caps great at lower freq but roll off as it climbs. So is very common to also use several smaller caps to handle the higher freqs. What is the clock freq in the A1? They need to filter 2x that frequency so the switching transitions can be dampened out.

Also is why high freq switching regulators use all them little caps vs a couple big ones.

Willing to bet that each cap is supposed to feed one of the big Vdd pads. And no such thing as overkill at this. Unless the copper plane are like 20mil thick, without that local bypassing you are going to see at least several 10's of mv unbalance and probably pretty weird spikes/dips/ ringing.

Bzzzt. Other way around. Caps in parallel add together. 1+1=2 ect. In series they divide. Resistors of course do oposite. series adds, parallel is 1/((1/r1)+(1/r2)+ etc.)