Topic: New Official AMT Thread - page 89. (Read 149472 times)

Yea, those seem to be the largest source of heat, once the cards stop functioning. May be the coils insulation failing. Those too, it seems, are not real flush-mounted to the board. There are exposed heat-pads under them, on the heat-sink side. However, the varnish actually raises the heat-sink from direct contact to the metal at all. (Looks like the heat-sinks should be machined to match the pads, but they are not. They are essentially using the heat-sink compound to "fill the gap" between the exposed heat-pad and the heat-sink, which is not the function of thermal grease. Thermal grease is designed to fill the microscopic gaps, not gaps of zero-contact. Which is where heat-pads are designed to function.)

Might also be why the heat-sinks are not showing as being needed, and the smaller ones seem to be over-heated. There is just not enough actual thermal-transfer to the larger heat-sink directly. Due to that large gap. (0.01mm is a large gap to thermal transfer, when there is 0 direct metal-metal contact. Not sure how thick the varnish layer on the PCB is. I would use aluminum foil shims, but then I need two applications of thermal grease. xD Plus, the grease tends to corrode foil. The silver/tin on the metal plates is already corroded. That should have been gold.)

I may just rip off the heat-sink on this one, make a pencil rubbing of the back of the board, and transfer that pattern to the heat-sink. Then grind it down by hand, to match the pads, for direct contact. Though, thermal-pads would be much better than all this extended effort.

One unit has a full sheet of thermal-pad across the whole backing. Not sure how wise that is... the cold spots will act as risers, not allowing the thermal pad to compress. While the hot parts will have an air-gap as the heated material thins-out. Though it will stop any possible shorting of the through-holes rubbing against the expanding and contracting heat-sink. (Which is something I also fear may be happening to the mystery working/failing card.)

Card completely failed today at 1:30 PM... Knocked the whole machine down to 0 GHs... Same as the one that had previously shorted. So now I am back to 385GHs. 1/3 of 1.2THs. (Still not sure why they sent me this. This is not what I asked for. They didn't ever reply back, about testing them, or send any testing information. So I assume they sent this as an attempt to fill my order. I got sort-of a mix of what I asked for, if a complete unit could not be sent, and what they were offering, but neither of any, but more and less. xD. I am so confused.)

This one was not missing any parts on it. All four of the CAPs and Resistors were where they should be, on each chip. There was also no screws-shorts on the cards.

Did notice another thing that bugs me a little, about the cards... The PCB sticks-out beyond the heat-sinks, by a fraction of a MM... This bugs me because the frame mounts firmly to the cards by the heat-sink, which has a metal-edge pressing hard against the PCB itself. This too stresses the PCB, and I am not 100% sure that the inner layers may or may not have any stray "copper traces" near the edges, which are in direct contact with the metal frame. Mostly, my concern is the compression of the PCB, as the aluminum expands and contracts from the heat. (This also being a concern due to the solid screw mounting which is firmly holding the non-expanding fiberglass PCB to the expanding aluminum heat-sink. Which is also being crushed between the mounting frame.)

Having the heat-sink in two separate halves would alleviate some of the expansion, if there was an adequate gap between them, and if the cards were not suspended by the heat-sink, through a firm mounting. However, that would require a complete redesign. The PCB would not sustain the stresses of the heavy heat-sink, in a setup like that.

You aren't wrong. we are doing AMT's job. I'm not getting compensated for this. As it is I am considering doing a closed distribution of this to a few people. Maybe down the road when I have refined the software I will make a more general distribution of it. But for now I am content with a closed one to a few people on here who want something working (if the software fixes it)

Hmm I just got an email from AMT....I got an invoice...balance paid in full and all that. Looks like they might be restructuring their records keeping process.....least to cover things. Wonder if the company has changed hands or something.

I would hope the next step is to get us all the working hardware we ordered for the invoiced amounts. OR if they are being forced into honoring the MPP that would be good too. At this point tho I am doubtful of any refund option or RMA. I just want working hardware I can hash with. I am stuck with what is a 500Ghs miner when I should have been hashing at 2.4Ths with my two miners. Quite a gap. Well hopefully the next email is that I am getting a product shipped for me if I got an invoice. (even though I got one already from them once before)

Thats not even happening either. That is whats pissing me off more now. No wonder everyone is coming down at them. Hell I have had suggestions to start other investigations since they are not responding to anything any more. Its aggravating. They are making enemies of people who supported them. There is a certain amount of leeway one can give a company when they mess up but damn this is retarded. They need to start at least trying to get something to us. I am guessing though the lawsuit locked them down though. Who knows we have nothing from either side to tell us anything.

Agreed, as I've mentioned several times before, if AMT does not want to communicate via the forums, they should be talking to their customers directly via phone or email. And also provide "technical" support for products that have been purchased.

/rant mode on

It's kinda aggravating that we have no communication from AMT or even feedback on the engineering work we are doing. We are essentially doing the job for them that they should be doing. The support, firmware work and all that is something we should not have to do outside of a hobby status. Its one thing to do this because we might not like the firmware we got. BUT when we are actually repairing and basically pointing out the engineering flaws without ANY feedback from them its a pretty aggravating situation. We paid for these things and on top of that having to barley get them working. trying to make the best out of a really bad situation but the LEAST they could do is actually respond to emails.

/rant mode off.

Can always just solder a length of twisted-pair out to somewhere convenient outside the shroud from the chip cap.
A shot in the dark - is the flakely board one of the ones with the 10k resistors in place of caps? If so could be that the remaining caps are starting to fail from excessive ripple currents.

Buck inductor temps are something I've never been comfortable with for various reasons. They are actually rated to run pretty bloody hot with max ratings often 140C or more. At least they are one of the few things that heat does not really affect until insulation failure. If you can keep a finger on it without branding yerself then it's good. I'd worry more about the solder connections to them failing from temp cycling and the heat getting to nearby components.

FYI if its a particular card, it's likely a precursor to failure. I had the same problem with 3 cards initially that worked before they died.

No, but I can get one... hard part is cooling while trying to probe, on a running card... Need a real big fan to run it without the shroud.

EDIT: (3:15 AM, oddball card is still running normal, so far.)

Going to make a per-card shroud and air-guide, to force air to the desired components. Seems to exit the fins and travel freely in the giant air-gap, which has less resistance, and not over the inductance coils enough. Again, this is where a tighter design and larger "wide" heat-sinks on the backs of the chips would really pay-off.

Got hold of some cheap Lexan. Came from picture frames someone was throwing-out. Free is always good. They are like Walmart frames, with cheap Lexan covers, instead of glass. Also got some insulation-foam-board, from construction they are doing at the place I work. That will make great space-filling material, to guide the air where it needs to flow.

Getting some click-pens, so I can pull the springs from them, to apply pressure to the copper heat-sinks. Just to test the idea. Just what I want... loose metal springs around all these electrical connections. xD (It was either that, or steel barrets, which use spring-steel, and are cheap at the dollar-store. )

Don't suppose your meter has hi-lo hold function does it? If does you can wire leads across one of the local chip caps and record the core voltage and see if it changes...

Just for kicks and giggles.. I powered-up the faulty card... Seems to be running back at full speed again. (10:21 PM GMT -5)

Getting about 590GHs now... It got faster! xD...

Seeing how long before it faults again, dropping back down to 20Ghs... It had about 4 hours of cooling time. Might be that the coils are not mounted well enough, and could gain from having a hat-sink on top of them too.

I have a few CPU heat-sinks I can chop-up to fit those. Just need some thermal-transfer pads. Don't want to smear heat-sink compound across those suckers.

I did notice that power consumption is up to around 800w (796w) at the wall, while the machine runs about 590GHs. Seems to indicate the crystal failing, or the driver circuit relaying the clock-freq, failing or falling out of spec. (Higher freq translates to higher workloads, thus, it seems to be slipping towards turbo-mode, though it is still set on nominal settings. Not pure turbo, but faster than nominal. Or, if it is the voltage regulator failing, it is delivering more power, and thus, also slipping/drifting towards turbo-levels. That, or the higher voltage is the result of the clock-crystal slipping.)

Wish I knew where to do something like that on the A1 boards...

Today I had another card just bottom-out. When it was dropping to 480GHs, it was one of the cards dropping down to 50-20GHs. Sadly, that was a card that ran at 208GHs previously. Not even sure where to troubleshoot that card. Like the one that was shorted, ironically in the same location on the backplane, it has done exactly what the shorted one had done.

I got about 3 days out of it... running at 208GHs. Ran fine the first day. Then dropped-out to 20Ghs... Reset the miner, it ran about 18 hours, then dropped back down again... Then ran about 12 hours, and dropped back down again... Today, ran about 3 hours, dropped back down... Now it only runs about 5 mintues, before it drops back down.

Obviously, something is decaying.

Showed no hardware failures an no errors... it just didn't run any faster than 20GHs. The coils were hot, but not the chips, this time. (Voltage regulator issue, or a cap issue?)

Too tired to rip the whole unit apart again, to pull the card. Just unplugged the card power. Hope the other cards work, but that still leaves me with a total of only 1THs of cards. Running only 380GHs now, off two cards. Glad I waited to RMA.



Red is the unusual spike... It was hashing waaay higher than normal. (I assume the initial drift-up.)

Green is the resulting failure... I caught it here, and rebooted...

Blue is the end-result, failing after a few hours before I caught it... Resulting reboot did not "fix the issue" this time. I just left it unplugged. The final result is only 2 cards running for the remainder of the day.

Also, along earlier lines  re: caps... Seems the earlier Ant s2 have an issue with that very thing. Bitmine has the info on where to add more across the local chip caps... https://bitmaintech.com/files/download/Guideline%20of%20Soldering%20Capacitor%20to%20S2.pdf

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...

Anyone who is a veteran use USAA to wire over their money? If so please contact me there might be some options there. Since Josh or anyone at AMT is no longer responding to anyone at all it seems, its time to get the banks involved as well and especially one that is for military and their families. Anyone getting any replies from AMT?

Anyone notice the new changes to the AMT site? Must have happened pretty recent. Visual changes it appears at the moment. Nothing in content. But still no word from AMT. No email, phone or anything at this point. Wonder whats going on.....or if we are even getting our replacement hardware....I essentially paid 11k for 500Ghs at this point. Not a happy camper.

Nice... Control... Just what we need to tune things.

Trying to figure out why my cards do not like to run for more than 18 hours... I keep catching them slipping down from 590GHs (3 cards), down to 480-380GHs. (Heat is not the issue, it was cold as hell the last few nights.) Seems software related. Since rebooting fixes it instantly. (Which takes a few boots for the cards to stop from getting stuck on the "MONITOR" stage still.)

It is like it may have a memory-leak, or if it is hardware, the frequency-controller is drifting. (Thus, causing it to reach the point of generating more errors, operating at a higher frequency. I'll have to see if it is errors causing the issue next time. If it is drifting down, then it may be operating too slow to sustain the cores communications. Or, with two separate clocks, it may just be falling out of sync. But that would be a hardware error. Guess an oscilloscope would come in handy to check that. I don't have a digital counter that can count that fast, accurately.)

But it does take about 18 hours, which I can normally catch. That, or just reboot every 12 hours. Not that big of a deal with only one machine. (This is where the 2 days, running for 24 hours would detect.)

Selling my thermal imager... Before the BTC hike starts. (Looks like less than a week, and I don't think there will be a final dip before the hike.)

I'll use some money to buy the things I need to finish this lexan case, and try to get the other cards running. May end-up just selling this miner too. If I put enough glitter and glow on it, I should be able to get close to what I paid for it. (Minus the $60 in BTC I earned over the last few days. xD) In the hike, I should be earning closer to $300-$600 a day. For at-least 30-60 days, when it is all said and done. That will be nice, but I would have made more just buying BTC directly, again. Would be more if I could solo-mine alt-coins... But pools will have to do for now.

We'll see how things go, once I get some of those supplies in, after my thermal imager sells.

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

Well they likley are barred from saying anything now. Considering their last statement that might be the case. I guess noone will know the compensation until this case is over.

In other news I figured out the driver issue. I am building out a driver for the at-spi interface which appears to not be set up (mistakenly assumed it was on pidora) I am hoping this works after a reboot.

Also I am going to setup PHPminer as the web interface for this firmware. Seems to work quite well for what we need.
https://phpminer.com/?page=screenshots

Once I get the driver issue out of the way and working I will update with PHPminer and put out an alpha 1 release. This will work for all coincraft A1 devices. Not just AMT's

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