Topic: Klondike - 16 chip ASIC Open Source Board - Preliminary - page 156. (Read 435369 times)

   DIY is an option if you have the nerve and the understanding that you will probably wreck some chips and the beautiful boards that BKKCoins is designing.

Having said that I am seriously going to allow some 13 year olds a shot at doing 2 or 3 K16 these boards... if they can do it well I will be impressed.

I meant that anything similar will do the job well for DIY 

Pretty much the same from China as I posted above. If you are in Asia Aliexpress even has free shipping from China as well as escrow.

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Get PROFESSIONAL grade version... check the link can dial in the temp.

Also posted some nice hacks for ovens that you can turn into reflow ovens. Also used reflow ovens available.

Again this was meant for people to READ the links and get an idea. From what I have read in detail it is possible with practice to do this at home with a heat gun or fine tipped solder iron given you can order professional grade units for reasonable prices. Rather than waiting for someone else or taking it a PC repair shop or sending to so one you on the forum you don't know. Again it is a risk and you have to know your skill level. This whole project started with the intention of being DIY.

It is quite doable given the right equipment and if you start practicing now you are bound to be proficient enough in 2 months.

I will be posting here in a few months time I hope in the fall with my students actually stenciling, bumping and then using a heat gun to reflow the ASICs to K16 boards. Of course I will be practicing my techniques with some used pcbs etc over the coming weeks with my own kit I am going to order online.
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For DIY i would use something like this http://www.ebay.co.uk/itm/New-ATTEN-AT-858D-220V-SMD-Hot-Air-Rework-Digital-Station-Solder-Blower-Gun-UK-/230977747273?pt=UK_Home_Garden_PowerTools_SM&hash=item35c758b949

or one of this http://www.ebay.co.uk/itm/T-962-INFRARED-IC-HEATER-REFLOW-WAVE-OVEN-BGA-T962-d3-/260756244588?pt=UK_Home_Garden_PowerTools_SM&hash=item3cb648886c

There are lots of stencils in ebay from Chinese suppliers. The only consideration will be the size of the solder point.

You have to make a stencil for the PCBs. For the QFN 48 there are some available. I plan on getting the stencils made to specifications from BKKcoins kicad drawings. Again if you are not sure what you are doing not worked even with a soldering iron before I bet your best bet would be to find a shop to do this sort of work for you. Take the chips and boards to someone else.

The stencils are something I was thinking of using. This is not included in the kit that BKKcoins is planning I think. If someone can come up with a supplier for this then you can purchase this separately. But again... do you plan on doing this DIY? If you are then you need to be reading the specifications, data sheets and getting some equipment lined up to do this. Otherwise DO NOT DO IT YOURSELF.

Get PROFESSIONAL grade version... check the link can dial in the temp.

Also posted some nice hacks for ovens that you can turn into reflow ovens. Also used reflow ovens available.

Again this was meant for people to READ the links and get an idea. From what I have read in detail it is possible with practice to do this at home with a heat gun or fine tipped solder iron given you can order professional grade units for reasonable prices. Rather than waiting for someone else or taking it a PC repair shop or sending to so one you on the forum you don't know. Again it is a risk and you have to know your skill level. This whole project started with the intention of being DIY.

It is quite doable given the right equipment and if you start practicing now you are bound to be proficient enough in 2 months.

I will be posting here in a few months time I hope in the fall with my students actually stenciling, bumping and then using a heat gun to reflow the ASICs to K16 boards. Of course I will be practicing my techniques with some used pcbs etc over the coming weeks with my own kit I am going to order online.

Thanks for the reply bkkcoins, I guess I'll just play the waiting game and keep lurking these threads. Not sure if I'll order chips now or wait till someone sells whole units for BTC. I'd just hate to order some chips and have to wait forever for someone to get to building my unit or deal with shipping chips every which way across the country to get one.

Dunno the lack of fan on the Rpi makes it seem more reliable to me!

I would be tempted to use an old netbook running on an atom processor as it would be easier to troubleshoot if anything goes wrong, but since I don't have an old netbook, I'll be using an RPi.

BFL did release Easyminer that runs on the Nexus 7 and various tablets so that might be an option but I haven't tried this yet.

2. Heat gun or professional grade soldering iron with a fine tip


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Good luck with a heat gun. How are you going to get correct reflow profile with a heatgun? Even if its temp controlled, you need a bottom heater. Also airflow is to high and you will blow your tiny components off the pcb. I have repaired many consoles where people thought that heatgun is great and fried their gpu chip during reflow.

What you need is either oven or rework station. With oven method, you use stencil to apply leaded solder paste, place components on the pcb, program  reflow profile, and heat the board and components only once and job done. With rework station you would do as above but welding process is done in sections rather whole board at one go.  In both methods crucial part is temp profile ( how quickly temp will be rising, how many segments are needed, what is target temp at each stage, etc.).  Unfortunately with a heatgun there is no way to control temp profile accurately so wouldn't recommend at all. You will be better off going soldering iron and fine tip way.

Once I get first test board, I will put it through my rig  and create reference reflow profiles if anyone is interested. It will still need a bit of tweaking as reflow conditions will be different for everyone of us  but its easy done.

I wonder what i should do. I have an old notebook that i will replace soon. But a raspberry would be nice too. I guess i will try it with the raspberry so that there is low power, steadily running computer connected to it all the time. The price isnt too big too. I think ill go this route then.

The RPi is already being used as hosts for the old FPGAs boards and there was a report that it also runs the new BFL ASIC (grnbrg on this forum I think has a dev unit working on the RPi).

However bfgminer/cgminer would need to have code added to support avalon ASICs regardless on windows/linux/etc.

While i see the videos about stencils and soldering paste... will the stencils be in the package? I mean i wont know what stencil i have to buy. In fact i dont even understand why you do it this way. I mean one could put a bit soldering paste in the middle of the chip and should get similar results isnt it? Similar to using thermal compound. And that its don on both sides? I wonder if it isnt enough to put soldering paste to one side only.
Now i see the question was asked already, but not answered. Stencil included for the whole board or only one chip. Or included at all. I think creating one single stencil will cost, but in bigger quantities it will be less pricy i guess. But when i read that a small stencil costs $11 already...

And to get it more clear... the chips are soldered with soldering paste and the capacitors (and similar things) are soldered with an soldering iron?

I thought about how to run the miner. I came up with raspberry pi but after investigating it a bit it looks like a raspberry only can run when powered by a usb. Its possible to run it through the house power grid when using an adapter for usb.
I wonder how good it would work with the raspberry. Anyone wants to use such thing too? Or maybe an old notebook is better.

What's your plan to cram 8x K64 in a 4U? Horizontally/ vertically? I can easily see 4 in a 4U, not sure about 8.

K64 for now is possible... a larger 40 x 40 board would need some rework and a lot of debugging I think is the issue. Not something most people need right now. And the K64 can be chained together fairly easily in BKKcoins plans so no real saving to be had I think right now. Besides the heat issues might make it hard to put 256 chips in that flat configuration and get the heat out so different configurations need to be tried. Align K64s like gpus in a housing might be the smart plan if you can arrange proper forced air cooling is the big issue I think. Have to test these things out and possibly share what we learn so that we can optimize our larger builds.

Oh, i thought the K256 was planned already. 2x2 K64 means 4x4 K16. I think when the K64 will work then with the same technique a K256 can be built. Or maybe a K576 = 3x3K64?
I only would like to know if the saved parts with this design would lead to an ven lower price. Of course if this cant be built i want to know too.

Multiple K64s daisy chained.... They can then be put together in a 40 x 40 arrangement of 4 x K64.

You will have to come up with some sort of design. I am looking at a 4U rack mount type system for 8 K64s so I can put it in a datacenter later.

Is there a special price for K256 or bigger too or is it a multiple of K64?

nah, i found terrahash, and it is what i'm looking for