and that ^^ is just one of the reasons that I refuse to support BM and switched to Canaan's Avalons several years ago. Ants may be more efficient but I will not tolerate nor do business with a company that operates like BM does.

Yes those screen shots look pretty horrid with the miners restarting every few minutes. One thing that can cause it is low line voltage as the 1047 PSU does not like a low line when trying to run at full speed.

Do they work better in "Normal" mode vs High Performance? Normal mode should put them around 30-31THs.
What in your AC line at? It must never go below 205VAC and preferred range is 220-240VAC,

Considering globalstar's links point to them being in Iran I have to assume that they bought through a reseller and not one of Canaan's authorized distributors because Canaan has none that service Iran. The only authorized distributor that *might* ship to Iran would be Cryptouniverse who are located in Russia.

If that is the case then it is the reseller they bought the miners from that they should name here and go after to get the miners fixed. Canaan cannot control what unauthorized and/or unscrupulous resellers do. All Avalons I have ever gotten (through Blokforge in USA) arrived in pristine condition.

I've been mining since 2014 and quit running Antminers in late 2016 because of reliability issues: the s1 through s7 were great but starting with the s9's I averaged 20% failures (dying hash boards) after just 1 year. After that I began running over 2 dozen Avalons ranging from the 7xx series to the current 10xx series and have never had even 1 major failure with them. Lost a couple fans after they have been running for about 2 years but that is the only problem I have had with them.

Excellent infobit that I had never heard about. Well deserving of Merit given.

As I bolded,the miner was not just shipped from Malaysia, it was assembled there as well- not China, ergo no Tariff.
For the umpteenth time here, only goods Made in China get hit with the Tariff.

@ freemine,
Please read the Deminimus thread here....
In short, regarding the Trump Tariff, what matters when importing gear into the USA is where equipment is built (made in China) - not where it is sold or shipped from.

BM, Canaan, Inno, and MicroBT (Whatsminer) all do it for the same reasons:

1. Increased efficiency by losing the hash board Vcore regulators and using the PSU itself to set and regulate voltage to the chips. That in itself helps eff by several %. Yes losing the PCIe connections & wires and instead using solid bolted-in-place bus bars also helps but assuming you have proper sized wires and connectors are in good shape there should be little loss from those.

2. Allows for higher chip string voltage allowing for more chips per-string which in turn divides up the voltage across each chip more evenly giving a bit more headroom for what voltage each wants to run at. Most of the built-in PSU's can provide 15-20vdc to the hash boards with the final applied voltage determined by the auto-tuning process.

3. Uses a PSU with known characteristics vs whatever bargain basement/unknown PSU a user decides to try using.

Because for the most part they were a crappy miner designed and marketed by a very unethical company (Dragonmint) and built for them by InnoSilicon.

Dragonmint of course imploded earlier this year. Because it is not Inno's design Inno wants nothing further to do with them. Best to let the things just die off and be rid of them.

There several different miners manufactured and we do not have crystal balls to know what you have....

A) What make/model of miner? They are all different and produce different amounts of heat.
B) There are NO 'quiet' fans that can provide enough airflow to keep any miner made in past few years cool when running at full speed. High airflow from fans at the pressures needed = loud. Period.

If you are up for building a custom case then use a centrifugal blower like used in a furnace. Only they can move the amount of air needed quietly.

No. ref https://bitcointalk.org/index.php?topic=763510.msg52866169#msg52866169 1 page back.

Even in regular pools where users share the rewards when it comes to any single miner finding a block the odds are the same as if the miner was running solo over any given change in difficulty. Only difference is that there are more folks rolling the dice which vastly increases chances of the pool getting a block and when one pool user cracks a block all share it.

Remember -- no matter what, it is just ONE piece of hardware that finds the block be that hardware a stick running 100GHs or today's latest beasts pushing over 70TH. We just hope to be the owner of that machine.

Yep.
That's what happens when a pool gets so small.

Perhaps there was however, as said earlier this is not a pool per-se.

This is more of a server site that anyone can access to mine for themselves (minus the 1% -ck gets) vs you having to setup your own node. How many others mine here and find blocks is irrelevant as the block rewards are not shared. Either way, ignoring differences in BTC network access and block propagation times to your node & miner(s) which would affect number of stales/orphans, your chances of hitting a block is the same for here or your own node.

For here "Pool Luck" is just a gauge of aggregate users speed at any point in time vs number of block found by that same point in time. Ja you can get a number for it but is meaningless in the usual sense.

ya gotta just shake yer head at such stupidity. Bottom line is that it is hard-currency aka Fiat that is the 'root of all Evil' as that is what any crypto coin gets exchanged into sooner or later. So following their 'reasoning' the production of all hard currency should be banned and everyone should move to a cashless system...

@ OP, there is a Deutsch area here

Which among other reasons is why I long long ago chose to stop supporting BM.
I prefer taking the Moral High Ground so efficiency and cost be damned, I simply refuse to support any company that operates the way they do.
There are more ethical companies out there (well, at least 1 - Canaan) -- support them!

IEC 13/14 and 19/20 connectors do not distinguish between 110 and 240V and there is no voltage-specific option for them like NEMA plugs have.

That said, the miner should have not even started up as the psu input was too low. There is at least 1 thermal device in it (inrush surge limiter(s)) that may have over heated. Did you try again after letting things cool down for 10 min or so?

Check Canaan's website for the distributor closest to you and get one from them. Make sure they know you want a fan for the 921 as most sites only list the A6-8 series fans.

 The 921 uses a 140mm fan - not a 120mm one like the A6/7/8's, & s9's etc use.
Just looked at one of my idle ones and it is an AVC model DBPC1438B2H  takes 12v @ 4.6A

Hmm. Seems someone has a youtube vid on how to repair similar ones so maybe give it a try? https://www.youtube.com/watch?v=qQkaGyoDWBQ

Yes and no.
Yellow is the tachometer feedback into the miner and tells the controller how fast the fan runs. Blue is the speed control signal. Red & black are DC power in.
4 wire fans use a speed controller inside of the fan itself to chop the 12v power as needed to set speed so just using a (high power, remember the fans take several amps of current) pot in series with the power MIGHT not work.

That brings up the fact that there are 2 types of 4-wire fans: The most common will run at full speed in the absence of a signal on the blue wire - signal on the blue slows it down.To test, cut the blue wire. If it goes full speed only then can you fiddle with an external speed control to reduce the red wire +12v.

If the fan runs at a very low speed it is the 2nd type that uses a signal on the blue wire to speed it up and that is what you have to modulate.

^^ Correct
If one bothers to look it up, all ASIC means is Application Specific Integrated Circuit. That can be anything: a watch or alarm clock chip, sound chip in a toy, crypto calculator, etc. Just means it is a custom chip designed to do 1 thing (or at most a very limited number of things) which cannot be changed. It is the actual circuit design and layout of the chip  - not its function - that can be copyrighted.

No, as it says in the title of this thread, there is a 1% fee.

Which would imply that it is a dual PSU.
If not, barring using 2 power relays wired to monitor each input and open/close the circuits (pricey & bulky) the only other way to isolate the power inputs so you don't (usually) have a live cord end when unplugged would be to use 2 bridge rectifiers, 1 for each power inlet, to give the raw DC that is fed to the switching portions of the supply. While it would mostly satisfy that safety aspect it also raises a few questionable design points regarding the current ratings of the bridge rectifiers and what happens if a portion of one shorts.

Either way, as a designer I'd go with the single high current power inlet even if it means breaking the mold of how it was done in the past. It's just the right way to do it. In my book since large farms already have to deal with the very different cases, power inputs just become another part of what they need to change.