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Author Topic: Hacking Bitmain Antminers (S7 & S9) because man a lot of these break......  (Read 1595 times)
lightfoot
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December 31, 2017, 02:52:23 PM
 #21

If Bitmain builds these chips and doesn't sell them, then I doubt a third-party is going to magically get the chips. It's possible they are selling stolen or bad run chips, but those would not be the kinds of things I'd want to stake my reputation on as a repair person for a client.

Back to the technical details: There are two types of S7 miners, 45 chips, and 54 chip versions. I was looking at a 54 chip version and noticed that I didn't see anything in terms of a set of FETs, power controller, or choke/inductor. That's because there isn't one: It looks like the damn thing has all the chips in a string connected directly to the +12v line.

Wow. Reminds me of the old AA5 5 tube radios from the 1930's where all the tubes were plugged into the 120v ac line. The problem of course is without some sort of a modulator a transient high on the 12v line will cause a lot of current to be drawn by the board. That could make the hottest chip (which has the lowest resistance) get even hotter and explode.

And good golly, what do we have here?


Yep, blown chip. Here's a close up of the scorched damage under the chip....


And note how on the back of the board the heat sinks that are not aligned are right in front of where the bad chip was. Almost as if they were blocking cooling air which made the chip hot which made the resistance go down which pulled more current, etc.....


I would make a guess that the reason for failure on this board was due to airflow not getting to the heat sink on that chip due to the poor placement of the heat sinks in front of it relative to the airflow. This creates a vacuum//turbulence point which means the chip will just get hotter. With chips in series like this design it's only a matter of time before that chip gets hot enough to short and burn out.

Moral: People should make sure their heat sinks are straight. It's possible this was done by someone after the unit was shipped, but since I see this on a number of bad S9 boards I'm thinking it might be a out of the box problem. Interesting.
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January 01, 2018, 02:15:30 PM
 #22

If Bitmain builds these chips and doesn't sell them, then I doubt a third-party is going to magically get the chips. It's possible they are selling stolen or bad run chips, but those would not be the kinds of things I'd want to stake my reputation on as a repair person for a client.

Yep, blown chip. Here's a close up of the scorched damage under the chip....



Another good reason to keep these units fairly clean and dust-free.  Not only does the accumulation of dust act as an insulator, but it also provides fuel for a fire.   I picked up a used S7 and it looked like it had been run inside a barn.  I wore a full on respirator to clean it.

Do you think, under the right circumstances, that this could cause the whole unit to go up in flames?  How well will green PCBs burn once they're in contact with flames?
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January 01, 2018, 02:40:38 PM
 #23

If Bitmain builds these chips and doesn't sell them, then I doubt a third-party is going to magically get the chips. It's possible they are selling stolen or bad run chips, but those would not be the kinds of things I'd want to stake my reputation on as a repair person for a client.

Yep, blown chip. Here's a close up of the scorched damage under the chip....



Another good reason to keep these units fairly clean and dust-free.  Not only does the accumulation of dust act as an insulator, but it also provides fuel for a fire.   I picked up a used S7 and it looked like it had been run inside a barn.  I wore a full on respirator to clean it.

Do you think, under the right circumstances, that this could cause the whole unit to go up in flames?  How well will green PCBs burn once they're in contact with flames?


How often do u clean the antminer. U use a can of airspray right? Do u also use air filter for your room intake air?

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January 01, 2018, 03:25:57 PM
 #24

Another good reason to keep these units fairly clean and dust-free.  Not only does the accumulation of dust act as an insulator, but it also provides fuel for a fire.   I picked up a used S7 and it looked like it had been run inside a barn.  I wore a full on respirator to clean it.
Yep. I have had small flames shoot out the end of one miner on the bench, it's short lived but an impressive sight. If the miner had been clogged with debris at the time it would have been a larger fire. And yes, I have gotten miners in that literally have hay and horse crap in them, seriously I can't believe someone would take a 5k unit designed for a data center and run it in a horse barn.

These are designed to run in a data center....

Quote
Do you think, under the right circumstances, that this could cause the whole unit to go up in flames?  How well will green PCBs burn once they're in contact with flames?
Possible, the question is what is on the other side of the exhaust fan. I doubt the PCB would catch fire right off the bat, but if something flammable was on the other end of the miner and the person was using one of those massive power supply busses that can feed a thousand amps into a shorted unit then yes, you might have a nice lint fire.

I recommend cleaning units every few months when they get dusty. Quick minute with a vacuum cleaner will do it. And don't run them in mines or barns.
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January 01, 2018, 03:35:13 PM
 #25

Gotta be careful with that vacuum cleaner though.  Wink

Because of the static electricity.

It is more safe to use compressed air instead.

Great thread btw once again, thanks for the efforts in the hardware section!  Smiley

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January 01, 2018, 03:49:40 PM
 #26

Another good reason to keep these units fairly clean and dust-free.  Not only does the accumulation of dust act as an insulator, but it also provides fuel for a fire.   I picked up a used S7 and it looked like it had been run inside a barn.  I wore a full on respirator to clean it.
Yep. I have had small flames shoot out the end of one miner on the bench, it's short lived but an impressive sight. If the miner had been clogged with debris at the time it would have been a larger fire. And yes, I have gotten miners in that literally have hay and horse crap in them, seriously I can't believe someone would take a 5k unit designed for a data center and run it in a horse barn.

These are designed to run in a data center....

Quote
Do you think, under the right circumstances, that this could cause the whole unit to go up in flames?  How well will green PCBs burn once they're in contact with flames?
Possible, the question is what is on the other side of the exhaust fan. I doubt the PCB would catch fire right off the bat, but if something flammable was on the other end of the miner and the person was using one of those massive power supply busses that can feed a thousand amps into a shorted unit then yes, you might have a nice lint fire.

I recommend cleaning units every few months when they get dusty. Quick minute with a vacuum cleaner will do it. And don't run them in mines or barns.

Yep.  I had feathers and animal crap inside mine before I cleaned it.  Some of the fins were completely blocked on the intake side.  Unbelievable.

And good point about the fuel sources in and around the miner.  I've tried to remove all the fuel sources around my miners.  I had a Asicminer Cube go up in flames on me and burn a small hole in the carpet.  So we're on metal bakers racks in the garage now.

Mine safely!
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January 01, 2018, 04:00:05 PM
 #27


How often do u clean the antminer. U use a can of airspray right? Do u also use air filter for your room intake air?

I used compressed air from my air compressor.  If you don't have an air compressor, you should consider purchasing one.  They're extremely handy for many-a-things besides cleaning miners.  Impact tools, filling tires, filling inflatable pools, dusting the interior of your car.  etc etc...
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January 01, 2018, 06:37:59 PM
 #28


How often do u clean the antminer. U use a can of airspray right? Do u also use air filter for your room intake air?

I used compressed air from my air compressor.  If you don't have an air compressor, you should consider purchasing one.  They're extremely handy for many-a-things besides cleaning miners.  Impact tools, filling tires, filling inflatable pools, dusting the interior of your car.  etc etc...
Kind of overkill to buy a compressor Smiley (yeah, I get it, it has other uses). I'd go for this instead: https://www.amazon.com/Dust-Off-Disposable-Compressed-Duster-Cans/dp/B00FZYT278
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January 01, 2018, 07:10:37 PM
 #29


Kind of overkill to buy a compressor Smiley (yeah, I get it, it has other uses). I'd go for this instead: https://www.amazon.com/Dust-Off-Disposable-Compressed-Duster-Cans/dp/B00FZYT278

2 cans for 12 bucks?  It'd probably take two cans per miner to do a good job.

Or a pancake compressor for 99 bucks.  https://www.homedepot.com/p/Porter-Cable-6-Gal-150-PSI-Portable-Electric-Pancake-Air-Compressor-C2002/203162815

Chances are, you're going to go through a ton of those cans in your lifetime using electronics.
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January 01, 2018, 09:17:40 PM
 #30

If you don't have a compressor, I recommend this instead of canned air:
https://www.amazon.com/XPOWER-Airrow-Multi-Use-Electric-Computer/dp/B01BI4UQK0
It won't freeze if you use it for long periods and it has a bit more flow than canned air (though maybe not as much as a compressor).  Also, it doesn't run out Smiley
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January 01, 2018, 09:59:28 PM
 #31

I used compressed air from my air compressor.  If you don't have an air compressor, you should consider purchasing one.  They're extremely handy for many-a-things besides cleaning miners.  Impact tools, filling tires, filling inflatable pools, dusting the interior of your car.  etc etc...
Oh yeah, compressed air is great. That and a pressure washer. You would not believe the amount of stuff you can do with a pressure washer, everything from cleaning the house to gutters to your shower tiles to cleaning baked on crap for a bitcoin board (just kidding)

For the really messy boards I typically use air to blow off the big crap, followed by 95% isopropyl alcohol, followed by air, then alcohol, then Q-tips to get the crud out. That pretty much does it, just have to do it outside in the yard....
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January 02, 2018, 09:10:45 AM
 #32


How often do u clean the antminer. U use a can of airspray right? Do u also use air filter for your room intake air?

I used compressed air from my air compressor.  If you don't have an air compressor, you should consider purchasing one.  They're extremely handy for many-a-things besides cleaning miners.  Impact tools, filling tires, filling inflatable pools, dusting the interior of your car.  etc etc...

I know can of air is safe. Is there any risk of electrostatic discharge damage if use air compressor or anything other than can of air?


I used compressed air from my air compressor.  If you don't have an air compressor, you should consider purchasing one.  They're extremely handy for many-a-things besides cleaning miners.  Impact tools, filling tires, filling inflatable pools, dusting the interior of your car.  etc etc...
Oh yeah, compressed air is great. That and a pressure washer. You would not believe the amount of stuff you can do with a pressure washer, everything from cleaning the house to gutters to your shower tiles to cleaning baked on crap for a bitcoin board (just kidding)

For the really messy boards I typically use air to blow off the big crap, followed by 95% isopropyl alcohol, followed by air, then alcohol, then Q-tips to get the crud out. That pretty much does it, just have to do it outside in the yard....

Isopropyl alcohol is safe to use without issues? Also, does this require opening the miner such that it voids warranty ?

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January 02, 2018, 11:07:17 AM
 #33

I know can of air is safe. Is there any risk of electrostatic discharge damage if use air compressor or anything other than can of air?

No such risk at all with compressed air.

Only if you use a vacuum cleaner, there is a risk for static electricity.

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January 02, 2018, 12:20:55 PM
 #34

Ali express has seller protection.  Alibaba you're on your own to negotiate a payment in a safe format. 

Try to agree through Paypal, or even Payment through Alibaba. Alibaba does give you seller protection, if you don't transfer to mysterious bank account from private chat.
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January 02, 2018, 12:46:43 PM
 #35

Nice work Lightfoot, i admire your tenacity and driven curiosity.

You are correct regarding the likelihood of the ASICs being counterfeit on Alibaba.

They are more than likely a generic chip with fake asic number screened over the chip.

HOWEVER, if you knew who the supply chain was for them in China that would be a massive plus.

I have always hated ROHS boards / solder and the cheap ass thermal adhesive compound chinese EMS use. Absolutely nasty QA and SCM of their BOMs.

Buy / assemble cheap / buy twice. Although they arent cheap which is scary.

Quietly watching on the sidelines mate and living vicariously through you.

I almost been a decade since i fired up the METCAL last.

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January 02, 2018, 05:31:20 PM
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 #36

It's possible this was done by someone after the unit was shipped, but since I see this on a number of bad S9 boards I'm thinking it might be a out of the box problem. Interesting.


Can confirm it is an out of the box problem. I have disassembled dozens of s9s while breaking the warranty seal, meaning i'm the only one since the factory to look at the hash boards, and a large number have poorly seated heat sinks.


One other thing of note, to everyone saying to use an air compressor there is one warning nobody has mentioned. Air compressors can get condensation inside of the air storage tank, which is why they come with bleeder valves. Make sure that you spray something like a piece of wood down first so you can see if moisture is being sprayed out.

I use something like this on my compressors:

https://www.amazon.com/Neiko-30252A-Water-Separator-Outlet/dp/B002GQ3SUA/ref=pd_lpo_vtph_469_bs_lp_t_1?_encoding=UTF8&psc=1&refRID=5TFZJ8TZ5Q486ZC943VZ

Stop buying industrial miners, running them at home, and then complaining about the noise.
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January 03, 2018, 12:07:16 PM
 #37


One other thing of note, to everyone saying to use an air compressor there is one warning nobody has mentioned. Air compressors can get condensation inside of the air storage tank, which is why they come with bleeder valves. Make sure that you spray something like a piece of wood down first so you can see if moisture is being sprayed out.

I use something like this on my compressors:

https://www.amazon.com/Neiko-30252A-Water-Separator-Outlet/dp/B002GQ3SUA/ref=pd_lpo_vtph_469_bs_lp_t_1?_encoding=UTF8&psc=1&refRID=5TFZJ8TZ5Q486ZC943VZ

That's a good point on the compressor and condensation.  Do you install quick connect fittings on this and put right before your spray nozzle (or tool) or do you install this closer to the tank?
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January 03, 2018, 04:36:09 PM
 #38

Just before the tool itself, I dont want any gunk going in the air tools or being sprayed on whatever im cleaning. I like the one i linked because it fits nicely in line and doesnt get in the way.

Stop buying industrial miners, running them at home, and then complaining about the noise.
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January 04, 2018, 10:58:40 PM
 #39

Quote
You are correct regarding the likelihood of the ASICs being counterfeit on Alibaba.
They are more than likely a generic chip with fake asic number screened over the chip.
There are no 'generic' chips that can be used for counterfeiting. Unlike say the USB-Serial converter chips from FTDI, mining ASIC's cannot be built up and (poorly) cloned using mask-programmed micro-processors or gate arrays.

Ja, if a counterfeiter *really really* wanted make a functional SHA256D ASIC then yes the mask programmed (and dirt cheap) route could work but performance would be horrible and not even come close to what Genuine chips run. The internal physical layout of mining chips are optimized to the nth degree for maximum throughput and trying to emulate them to burn into blank gate arrays just does not work anywhere near as fast.

That leaves the chips as either improperly disposed of (stolen) rejects or a relabeled other kind of chip. Either way has SCAM written all over it.

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lightfoot
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January 05, 2018, 03:13:04 AM
 #40

Thus not something to use. Meantime been working on a few more S7 boards and Titans, never dull in this world.
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