Thanks.

That mess of conductive paste is horrendous.

Well done for fixing it - I would not have liked to remove that crud myself.

Yes of course - pictures of the device disassembled that is.

I don't think an employer would make a big fuss about an Antminer U2.  After all it is about 3W - about £3 per annum.

Of course something using 500W is another matter

The device has hash rate of approximately 150 GH/s
The world hash rate is approximately 300,000,000 - see https://blockchain.info/charts/hash-rate

see https://bitcointalk.org/index.php?topic=889538.0 where a similar question as asked.

1)You are the first person to have suggested that this is a beginners device in this thread - One other person used the term introductory.
2)Shouting - the use of capital letters.
3)Yes the ones on Amazon that you get commission on that people said failed after a short time.

You have made a number of loud negative remarks in this thread showing a lack of respect for other people's opinions.
This time you use bold type to emphasise your opinions.
The discussion in this thread has been about obtaining samples, making boards, FETs, power supply efficiency.
You are out of order Dogie

Let's keep this to talk about engineering and assuming a level of competence.

Exposed terminals - shock horror - and why the shouting ?

You should lie low after having recommended duff 12V supplies.  We're talking reliability here.

Perhaps domestic drivers for LEDs would be a good choice - if they produce 12V and don't try to drive a constant current.

It is too soon to say.

I have 4 Antminer U2 (combined hashing power 8GH/s) but it has taken me 3 months to mine 0.01 Bitcoins - (this is the minimum amount that https://www.triplemining.com will transfer) - value about €3

I suggest that you monitor https://bitcointalk.org/index.php?topic=875392.0;all for news about the Technobit "DICE" 160Ghs Entry miner/blockchain personal lottery device. It has 20 times the throughput of my installation.

In the meantime purchase him a Raspberry Pi B+ which it is to be hoped he will be able to use with the Technobit DICE and he can use it for many other projects.

These calculations are approximate I think.  If one redoes the calculation with 40 years (instead of 1) it would give a probability greater than 1 (impossibe) - and as we know the probability is less than 1.

"DICE is delivered with set of Win/Linux software" - how is it delivered ?

Has Ckolivas been involved with you in producing updated cgminer s/w for you ?  Can I drive a Bitmain U3 with your software ?

Where do you get the "10" from ?
There are 6 chances an hour so -

6 x 24 x 365 chances a year => 2.6% chance of winning in a year

I don't want to buy a TP-LINK - I want to use a Raspberry Pi B+ and compile an official cgminer on it.

Thanks for the suggestion   I have been toying with the idea of buying one of these.

I still like the idea of using a Raspberry Pi B+.  I think one could connect 4 of these miners as it has 4 USB ports and I could compile cgminer on it if needed.  I would run tightvnc on it so that I could monitor it remotely.

Perhaps one can do all these things with a TL-MR3020 (except for the 4 USB ports) if flashed with the appropriate firmware but I suspect that the Raspberry Pi's community would help me think of other applications that I could run at the same time.

This seems a much more sensible device than the Bitmain U3

It has a higher hash rate
The power consumption and therefore heat dissipation is such as to make it a reasonable domestic heating device without it being excessive in a European winter
Because of the rectangular construction and horizontal heat exhaust, they are amenable to stacking vertically
One can choose the power supply one wants
The comparison with a lottery device is clever

At £0.15 per KWh it would cost £3.024 per week to run if one assumes it requires 120W
With Bitcoin at €300 the expected return per week would be (25*300*6*24*7)/2000000 = €3.78 (One over 2 million is the chance of it finding a block in each 10 minute interval.

On the minus side delivery (to the UK) is €32 giving an all in cost of €110 ?
I have not factored in the price or running costs of a Raspberry Pi, SDHC card and power supply
The technical information is sparse. (absolute maximum ratings ?)

Then there is the question of reliability - On Technobit's website (for another product) there is a cgminer screen.  It shows the best share as 73.1K for a hash rate of 368.7 GH/s - this suggests a short test duration (looking closer 6 minutes in fact).

If you would normally use 120W 24/7 for heating, the expected bitcoin return would cover the device cost in approximately 30 weeks (with no increase in difficulty)

£1 = €1.2 approximately

The more I read here, the more it becomes evident that Engineering has been over-ruled in favour of Marketing, Sales and artistic design.

Any chance you can give us a look inside - cover off, then fan removed ?
Thanks

In another thread (I forget which) a link to a 30x14 cm (half a square foot) heat sink from Shenzhen was posted http://www.ebay.co.uk/itm/300-140-20mm-Aluminum-HeatSink-for-LED-Power-IC-Transistor-Module-PBC-/321199970078?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item4ac902971e

By buying parts for a miner separately and putting them together oneself, one can avoid paying VAT.  All that is missing is an economical board from Bitmain.  If Bitmain wants to democratise mining they have to make a product that stands some chance of recouping its cost.  It is most unlikely that the U3 is that.

The threshold for UK 20% VAT is £15 (For duty it is £135) ie USD 23.96 http://customs.hmrc.gov.uk/channelsPortalWebApp/channelsPortalWebApp.portal?_nfpb=true&_pageLabel=pageTravel_ShowContent&id=HMCE_CL_000014&propertyType=document#P20_1804
 Postage is not counted for ordinary mail.

https://bitmaintech.com/files/download/BM1382_Datasheet_v3.0.pdf gives 14.18 GH/s at 0.528 W/GH (Core voltage 0.72V, current 10.4A, Power 7.49W).

So the question is how many of these could be put on a board with a microprocessor, hopefully a switch mode power supply and a USB interface for $23.96.

Note that I've used the value 0.72 V whereas elsewhere in the spec the minimum recommended core voltage is 0.75

The situation in Europe seems to vary country by country. In France there is no threshold it seems, whereas some countries have a threshold of €22.  Germany has a threshold for VAT of €22 but if the total VAT is less than €5, it is waived so the value could be up to €42 USD 52.41 (slightly more actually as Germany's VAT is 19%)

(The information for Europe I obtained from http://www.dutycalculator.com/ - but after 3 searches they ask for money and though I flushed my cookies it did not seem to help).

I think that you will find that the Raspberry Pi B+ is much improved.  It can supply more power to the USB ports, it is more efficient (it uses switched mode rather than linear regulation to make 3.3V) and the USB software has improved with later versions of Raspbian.

I am using the B+ and the second generation B with CGminer with Antminer U1 and U2 devices.  The only problems I've had have been due to my powered USB hub dropping too much voltage when powering these devices.  My systems are now rock steady.