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Okay there was and is a nice thread by Danieleither.

https://bitcointalk.org/index.php?topic=5490991.msg63879624#msg63879624




It talks about buying T21 units and getting stuck with three phase power.

I did the same as Daniel in fact I ordered three 1 just came with 2 on the way.

I have single phase 230 and was really angry.


But With some work and looking for ways  some I found some are on danieleither thread.

I have a working t21 using a 230 volt psu .

quote of myself below

"my meter reads 2782 watts for 157th that is about 17.72 watts a th"

the software number reads high 3050+

https://www.talkimg.com/images/2024/04/06/V5xrv.png

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so some power numbers

157th with cold air 45f open garage door  burns 2750 around 17.7
140th with cold air 45f  garage door burns 2460 around 17.5

will do 175th next.

spacer.


Parts needed a bitmain T21 miner

the correct controller I have the Civtek it is no good.

the epic controller with firmware 42 is mint and works.

proper buss bars. I ordered them from Altairtech but got short ones.

my s19xp has the right buss bars.

a s19 psu.

parts list from altairtech.

controller
https://altairtech.io/product/epic-umc/

psu
https://altairtech.io/product/epic-umc/

four pin pwm fans as the fans that come with the t21 have wrong connector.

epic controller wants standard four pin fans.

https://altairtech.io/product/antminer-120mm-replacement-fan-for-s19-s17-s11-s15-and-s9-series/


Note the
bus bars I ordered below are no good I will ask Altair-tech to check the rest of them. so they do not get sent to you and they are short mine were under cut by ¼ inch.

https://altairtech.io/product/antminer-power-bar/


I am tired will post more later tonight.  edit the buss bars are not long enough

https://www.talkimg.com/images/2024/04/08/VbLdT.jpeg

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garage door shut room kind of warm watts are  2868 hash 157

https://www.talkimg.com/images/2024/04/06/V7MQG.jpeg


garage opened cools off around 20-30f

https://www.talkimg.com/images/2024/04/06/V7mYD.jpeg

with temps cooler watts drop 2758/  th 157 = 17.5 watts a th for the t21 pretty fucking good.

https://www.talkimg.com/images/2024/04/06/V768f.jpeg

here it is set to 180 th.

note it says watts are 19.1

meter gives me 18.5

and if I open the garage door to cool room meter gives me 17.5 watts

a nice piece of gear. two more on the way.


https://www.talkimg.com/images/2024/04/08/VpXuG.png

I am very ambitious about these T21's

I purchased an alpha miner psu.

It can do 7000 watts it is meant for liquid cooling I intend to

A) mod it for air cooling
B) use a buck boost transformer to boost volts to 255

add this setup to the T21 the psu can do 300 volts
the transformer can do 7000 watts.

in theory the t21 can over clock to 230 th
in theory the alpha psu can provide the watts needed.

This will take until late may as the next 2 t21's come in may.

Happy to see folks trying to get T21 to work on single phase. We've done this on a couple of test rigs and can't really tell a performance/efficiency difference between T21 and S21.
Yet the T21 is considerably cheaper, and comes with a Bigger PSU.
One issue I've encountered is that after you change the PSU and power bars, there doesn't seem to be an easy way to cover the power bars etc, since T21 does not come with a PSU cover piece.

yeah and the s19xp psu I used the cover does not quite fit.


I have three of these t21s i can get them to do 205th at 17.5 watts in a cold room.

i am going to experiment with the alpha 7000 watt liquid cooled psu. in theory the t21 can clock to 231 th with the correct psu.

Hey Phillip!
Any updates on this project? I have some T21's and some S19 PSU's. I'm thinking about trying this out. Frankenminer FTW!
Altair makes a cover for the power bars for this conversion. Not sure if they sell it seperate or only in their conversion kit.

Runs great so far.

I used black duct tape to cover the open buss  bars.

I am getting two more t21 s maybe I will ask Altair tech to ship a cover for them. I will need some more parts.

Get the epic controller and use firmware 42 or 44



I have run it 60th to 195th zero issues.

And on colder days it can do 17.8 watts a th at 160-190 settings.

Heat can make you do 17.8 to 21 watts

Just shipped you a couple of complimentary T21 Transformer PSU covers.
The bars aren't a shock risk but still pose short circuit risk.

Is the epic controller necessary? Altair does not list it as part of their conversion kit. I'm thinking I can use the stock controller and flash it to vnish.

That's super cool Altair!

don't know if that works maybe it does.

T21 stock firmware errors out on APW12, so you would need aftermarket firmware to run after swapping PSU from APW11 to APW12. For the fully assembled 'T21 transformer' we just ship with vnish on stock AMLOGIC control board. We have tested this build with both ePIC UMC and MARA UCB and it works with both, but they do add some additional cost to the build.

Both these CB options are nice since they have zero dev fees , so will likely pay themselves off over time.
But if you're looking to save on upfront cost, you can just flash luxos or vnish on the stock AML CB and it works fine.

Now if your T21 came with a CV1835 control board, that changes the math, since there is very few firmware option available. In this case, your best bet is to just remove the stock CB and replace with epic or MARA.

Yeah I had the cv1835.

I ORDERED and received some epic boards for the two t21 units coming this month.

I rave on about epic boards as I have found them to work better than any board I ever used.

I will end up needing 3 covers to prevent shorts. The electric resistant duct tape is sloppy looking.

I have a ton of psu's from my s19s.

I hope to end up with 4 or 5 miners once I sell off all my other gear.

One L7
THREE MODDED t21's
Maybe a gpu rig.
Oh two nano 3's

This would do about 14kwatts an hour.

I'd be interested in buying some covers.

S21 is better than T21, most of our clients choose S21 instead of T21

I've listed the PSU cover as a variant on the T21 transformer listing
https://altairtech.io/product/bitmain-antminer-t21-transformer/

Do you know you shipped the covers out the other day and in under 10 hours bitmain shipped my remaining  t21's

I will soon have 3 of them up and running.

the s21 is not worth the extra money than the t21 in almost every case.


model s21          t21
hash   200th vs 190th
price   3780  vs 3059.    you save 710 usd the mode is about 210 so you save about 500 bucks.
watts. 3700  vs 3700


the t21 ships faster

10 th earns 50 cents a day.  so it takes 1000 days to make up the 500 extra for the s21

and I am not counting that you can sell the psu that you pull out for 250-450 on ebay


https://www.aliexpress.us/item/3256806711358754.html?


plus the power cord https://www.ebay.com/itm/186397914642?



So if you get 300 for the oem psu and the power cord you were paid to do the mod

this mean you save 800 on the t21 not 500 at 5 a day that is 1600 days before the s21 goes past the t21

So I kind of feel sorry for people that did not go for t21's and mod them like I did.



Now if you read all that I said I was pissed to start when I found out I need to mod my gear but I ended up making out better with the t21's

I think any hands on person should consider the t21 as pretty much an equal to the s21

I just got my first T21 working on VNISH firmware. Set it for 175TH just to see how it stabilizes. Very exciting! I too was quite upset when i opened up my T21's and realized it was 3 phase power. I am so glad that I am able to convert this to a good miner just using my S19j pro power supplies from backup miners. Im going to model a cover and put it up on thingiverse for anyone that needs it. Sorry altair, i really love and appreciate the bus bars, but im not gonna pay $20 for someone else to print me a cover. And unfortunately they dont sell the stl.

yeah I can understand not buying a cover.

but I can tell you Altair has helped me time and time again.

They also help this website a lot.

My apologies!! Rereading my post and i made it seem like i was dogging on altair. Nothing could be further from the truth. They are an amazing company and i am very grateful that they have the parts and pieces we need.

The 3d printing thing is only cause im a curmudgeon who prefers to do things themselves :P


Also, the old s19j pro power cover mostly works in a pinch. Thats what i have on my (2x now!) T21.

The mod is extremely easy folks, takes 30 minutes including firmware install. Buy dem T21s!!