We are also having a bit of an issue with Blokforge.

We had ordered a few additional S19's for the farm that were 'in stock' over the course of Aug and Sept, a couple at a time, and BF shipped within a few days of each wire transaction. The last shipment came late Sept and was fine. On Oct 20th we had an older machine fail, and I ordered an S19 to replace it, wired funds, and receipt was confirmed on Oct 21st. Since then we have heard nothing. Machine showed in stock, still shows in stock. 4 inquiries now have gone unanswered. I suppose I'm glad it was just 1 machine, and not say 10, or 50, but it bothers me that they are holding $12,400 in our funds and no contact going on 3 weeks now.

One begins to wonder what's going on over there. Are they just short staffed and super busy?

I was ready to pull the trigger on up to 10 PRO's @ up to $1700 each, but $2360? That's $3000 per machine including the tariff to nets > $7 a day at 8 cent power @ current difficulty & BTC price.

Even if I still had the March coupons it would have been a pass. Should have gone to bed.

Note the voltage rating 200min-240max and the warning:

     Caution: Wrong input voltage may probably cause miner damaged

Looks like dual power inputs on the PSU.

Anyone care to speculate on the prices or if they will limit purchase qnty per customer of the 1st batch of units?
With BTC up I bet they are gonna be pretty expensive.

The rumors were that the Gen 1 7nm process had terrible yields and that bitmain only had enough good chips to build a few thousand S15's, and due to the low yields they had to sell the machines below cost. It might be true. That would certainly explain the purchase restrictions on the first few batches, and short period of time they were available for shipment. I would imagine that the yields on the gen 2 chips will be at least as bad. For all the Gen 1 7nm they shipped, the network hashrate is still below were it was mid-Nov, and has probably been supported in large part by keeping older gear running via all the dyscalculia suffers that bought up those BitDeer contracts. But we shall see. If the price makes sense, and the specs pan out in the real, I'll be picking up a few S17's for the farm. If. When. Maybe.

You know you are running on crypto time when 60-90 days from now ISN'T the 'near future'. 

Since this is the speculation thread, I would speculate that initial yields on the new 7nm chips will be so low that the machines won't be available in any significant qnties for many months. Not crypto many, but real many. So I would not be too concerned about any sort of big difficulty jump. A couple thousand machines will barely be a rounding error and a lot of them will likely go to replace older gear. The first batch for pre-order will probably get the best chips from the first tape out as well, and will also be the most expensive.

That was me. I tried 2 units at home back in January on separate 30amp 240v circuits, one in my basement and one in my garage. These are circuits I ran S9's on all last winter. Both S15's PSU's failed or fault tripped resulting in no power at slightly above 240v. My multimeter tests those circuits around 240.8v on average but they can vary +/- a couple of volts. One S15 failed almost immediately, within an hour, and the other ran for around 10 hours before crapping out. Both PSU's were noticeably hot prior to failure. I suspect the basement unit failed first due to the ambient (around 60f) being warmer so it over heated more quickly. The garage unit ran longer (ambient around 25f). Both units were returned to Bitmain CA under warranty repair tickets and were replaced directly from China in about a week.

We currently have 43 S15's running at the commercial farm on 208v, some for nearly 2 months, without any failures or issues though we did get one unit that had a bad hash board. Bitmain also replaced that unit under warranty in about a week.

I would not attempt to run anymore units at close to 240v without a step down transformer. Other than that, they have turned out to be fine gear. I have no complaints. They are all 28th/s units. Collective average for 43 units is 1.2Ph, so all machines are running very close to spec at 208v and 50-60f ambient mining room temp. Curious to see how well they hold up a couple of months from now once our mining room starts to get hot. We do intend to switch them into LP mode once the ambient starts getting into the 90's and mine them like that during the course of the summer.

One note - all 3 of our warranty replacement units seem to have come out of China stock and do not have the power rail covers, they are the open rail design. All other units we received have the rail covers.

Keeping the unit low spec will also minimize the power loss factor. 1.5% is excellent, and the price is right as well.

The Larson transformer I was looking at was 11KVa (TX2402081P11KVA) 240v to 208v (max 53 amps) and costs about $600. I could run about 5 S15 off it with a solid safety margin but it would require extensive rewiring of my circuits.  Not worth doing for a couple months of heat at the house.

I took 2 S15's home (to run for heat) on my 240 outlets and the PSU's on both units failed within 24 hours. Both PSU's got quite hot. I think my 240 outlets actual voltage may vary a little higher than that, maybe 242 or 243. They may have simply tripped a safety shutdown due to either voltage or temperature, but regardless, both ceased to function (no power) there was no way to reset them. Both units went to Bitmain and were replaced under warranty. I will not attempt to run anymore of these at or near 240v even though the spec says 200-240v. They seem to be happiest somewhere in between those numbers. I've had some units running nearly a month on our 208v rack with zero issues.

I was looking at a Larson Buck transformer to change the 240 at my house to 220 or 208 so I could run a couple of S15's at home, but it's not really cost effective. Also, they show a 3-4% loss of efficiency in the windings due to heat loss. I don't think you can step down the voltage with any device and not experience a certain small loss in the process, so keep that in mind when calculating the cost to run an S15 vs say an M10. With a transformer an S15 might end of drawing 60 or more w/per TH. It would be great if Phil could test that on his device.

We now have 28 S15's running on the rack at the office now on 208v, and they are functioning perfectly. They are all 28TH units. The min to min hash rate variance is higher than spec, can be up to 15% either way, but the daily average of the units collectively is 783.9 TH which = 783.9 which is 27.96TH per machine on average, so they are running exactly within spec on our 208v supply. Power draw is averaging 1590w per unit. That's based on the total draw on our panel. I haven't measured individual units.  We're using Triplite 3' 12awg power cables from the PDU to the units. One miner per PDU circuit, 2 miners per PDU so the breaker on the PDU's become the power switches. The 12awg cables are to minimize loss more than anything else, I don't think we would have any trouble using 14awg cables for these as long as they are short. This is all equipment reused from the S9 farm.

Bitmain replaced our 2 units that failed on 240v+ for us under warranty. One of the replacement units came with the 'open power rail' design (which bothers me greatly). All the other have the power rail covers.

Oh, also, the DHCP network problem we had with the 2nd batch of arrivals was unique to that batch, 6 machines. We had to plug those into a small router and scan for the IP address, then change the settings to a static IP on our network. All of the new arrivals come up on our network fine at boot.

I'm not sure. We have a Cisco router that is up to date and latest firmware. We have 36 Z Mini's and at one time 104 S9's of every generation running on it, plus maybe 20 odd computers and devices around the office. We always assign static IPs to the miners, but allow a pool of 50 DHCP addresses for miner bootup and for the other devices that don't need assignments and for wireless devices. Never had a single problem before. We tried swapping cables and even direct connection to the router past the switches. I did open up a ticket with Bitmain support and she said it could have something to do with the way the controllers were flashed. The three units we had trouble with do have the black label around the network port and control panel, and the others do not. I'm not sure if there are any differences in controller hardware, but at Bitmains suggestion we did swap a controller from a working machine to a non-working one and the machine worked fine with the other controller.

---

The last batch if 10 S15's that we acquired was during that little blip when Bitmain was selling them for $1050. Between that and the coupons we had, it paid for the tariff and shipping. The M10 looks like a good machine but @ 65w/TH the efficiency is too low. We're planning to deploy a total of 36 S15 by the end if Jan and run them full power the rest of the winter. That will give us 1PH. Then change them over to LPM starting in May when we start to have cooling challenges. Our mining room should be able to keep up with the heat very well with 36 machines running 850w ea + the Mini's, and we will be mining at a more efficient ratio during the May-Oct when our PoCo increases our electric rates slightly. In order for us to keep our contract rate with the PoCo we have to draw at least 60KVa 24/7, and in July I want to renew that contract for one more year. We subsidize the electric cost for the mining operation so this will make that more manageable and I'm hoping this last equipment upgrade will keep us mining until the halving. Can't really see beyond that, but I don't think there will be anymore new form factors or revolutionary new increases in efficiency in the next 18 months, so this is what we came up with to keep us mining for one more generation of gear. We can support up to 80 S15's on the current rack (we have total capacity of 150KVa), and our power cost goes down the more we use, so if the gear gets cheaper later in the year we can add more capacity if conditions look favorable. We've been mining since the S5's, so this will be the fourth cycle of gear we've gone through.

Also, I would like to give a hat tip to BitMain. They received the first warranty repair miner (one of our S15's that failed on 240v) in CA on Wednesday and dispatched a replacement unit from Shenzen this morning, it's due to arrive UPS on Monday. So about 10 days turn around from VA. Never thought I'd ever say that.

Yep, Northern Virginia. We have 8.4cent power on an annual contract with the PoCo here.

So, update. we got 2 more S15's in today. These are 2 of the 27TH models. Put them on the rack and they came right up on the network. So for the 3 that were giving us trouble, I took a laptop and a little VPN router that I have and direct connected each unit to the laptop via the router, then ran WireShark and found the IP the S15 was broadcasting. That got me in, and I programmed a static IP to each S15, reconnected, and they came up just fine on our regular LAN. Not sure what the issue with getting a DHCP assignment is for these units (they are running the same firmware versions as other units that worked fine to begin with). In any case, have 18 on the rack now running 100%. The two units that had the PSU problem at 240v already went back to bitmain for warranty repair.

Onward and upward.

Definitely have normal connectivity lights. Machines boot as normal, all lights normal, but cycle due to not having a network connection. When we plug them into the connections of working machines, they do not come up. All the miners on the network are static IP, but we have a DHCP range set aside on the router for new machines. We boot them DHCP and then assign static IP's.  Power cycling and resetting the machines does not help. Switching PDU, power cables, and NIC cables doesn't help. Units do not show up in our routers control panel of connected devices. I thought perhaps they had shipped us units that had already been assigned static IP's, but a factory reset would fix that. I though maybe the NIC's were being finicky with our gigabit switches, so I put them on a 10/100 switch and also plugged them directly into the router. No joy. Not sure what the problem is, but if the controllers aren't bad we'll figure it out.

Our s15 adventure continues. This morning we shipped the (2) S15's that failed on 240v to the CA repair depot. This afternoon 10 more S15's arrived from BitMain. We put them on the 208v rack at the office. Of the 10, 7 work perfectly and 3 will not show up on our network despite all efforts and troubleshooting. Can't figure it out. So now I have 13 S15's running, 2 going back for PSU, and 3 that boot up but won't communicate with the network. I wish I could get ahold of a couple of spare PSU's and controllers for these guys. They aren't selling S15 parts yet, are they?

No, nothing. Units are totally dead. No Hash boards, fans, or lights on the controller. Re-power produces nothing. Leads me to believe that the PSU's failed due to the voltage. Really want to open one up and do some testing.

philipma1957 is probably right, the voltage from my 240 outlets here at the house probably varies by couple of volts up and down. When I test them I was reading 240.8v. Most appliances designed for 240v power have an outside operating range of 250v due to variance. Not these guys, apparently. Oh, was definitely running them full power mode. They were running about 28.4 when they were up. I should have switched the other unit to low power mode when the first one failed, but I wasn't thinking it was a voltage issue until they both failed.

I was thinking that too. Did try to re-power the units a couple times over the course of a few hours, but no luck. One unit was in my basement, about 60 degrees ambient and only ran for about 45 minutes. The psu on that unit was quite hot to the touch just after it lost power. The other unit was in my garage, about 35 degrees ambient. That unit ran for 11 hours before it lost power, again, the PSU was quite hot to the touch. I put a meter on both the outlets and they tested 240v. I will take both S15's back into the office Monday and put them on the rack at 208v and see if they power back up, or if something inside the PSU is actually blown. I would like to open them up and do some power troubleshooting but I don't want to void the warranty in case they need to go back. Bitmain doesn't seem to be offering any spare parts for these yet. I don't know if my experience is typical but I wanted to throw out a word of caution if anyone else is operating these at the high end of their voltage rating.

What input voltage are you guys running these at? The 8 S15 28Th units we've been running on our rack @ 208v since Monday are all functioning perfectly. Two units that arrived yesterday that we setup at a different location on 240v ran fine initially but both failed within 12 hours. PSU dead, no power. The card included with the units shows a rated voltage range of 200-240v.

Has anyone seen any detailed specs on the S15's PSU? 127/220 is a common industrial voltage output from 3 phase service in many parts of the world, but we run our farm on US 3 Phase WYE service which gives us native 208v. It's doesn't appear that the new BitMain gear is being designed for the US market, but I'm thinking perhaps the input voltage specs may actually be a little more flexible than what's being shown.

Any who, reworking the farms supply panel or adding boosters for this gear would make it cost prohibitive, as if it isn't already.

One of my guys here was doing a lot of hand-wringing a couple of weeks ago (when coin was around 8k) and asked me how low I thought it could go. I told him that I didn't think BTC had any chance to get out of this bear market and realize any organic price growth again until there was total capitulation of the interests that invested during the bull run last year. I mean idiots were buying coin with their credits cards and FASA funds for Christs sake. All of last years speculative malinvestment needs to be wiped out before there can be a turn around. I speculated that perhaps it would require a $3000 price level to do that. That's usually how a healthy business cycle re-establishes itself after a big speculative run-up / bubble burst.

Just wake me up when its over.

Avalon 741's reduced to 0.06 BTC each delivered (inside CONUS).

I have (20) Canann Avalon 741's we are retiring from our farm to make room for different gear. 0.06 BTC each delivered (inside CONUS). All units include cables, are in excellent condition and will ship in their original boxes. We're very fastidious in how we take care of our gear. Units are 6 months old or less.

PSU's not included, but I do have 12 excellent condition EVGA G2 Gold 1300's (110-240v) that I would like to sell. They would be 0.022 BTC each delivered (inside CONUS) as long as they are ordered with a miner and would include all cables. They are less than a year old and are covered under EVGA's 10 year warranty.

I'll be letting go of two more Avalon controllers as well. 0.011 BTC each delivered (inside CONUS). Each controller can run up to 20 miners. Of course, you can also buy a Raspberry Pi 3 and download the software from Canann. That's the best route to go rather than pay double for a factory controller.

Shipping from Winchester, VA via FedEx ground, fully insured. Expedited 2nd Day shipping (inside CONUS) add 0.005 BTC per unit. Shipping outside the US available. Can quote upon request. Serious inquiries only please.

Can accept payment in BTC, ETH, LTC, or ZEC. No BCH please.

PM me if interested. Thanks for looking!

Bob