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141  Economy / Service Announcements / Re: [ANN] Bitfury ASIC sales in EU and Europe on: September 07, 2013, 11:12:11 AM
I don't know where to get them in small quantities. I get them as 5000 piece reels for 5 EUR from Farnell.
142  Economy / Service Announcements / Re: [ANN] Bitfury ASIC sales in EU and Europe on: September 07, 2013, 10:38:47 AM
For a more durable way to overvoltage the boards you should replace resistor R01F. The nominal value is 1.0K, and to increase the voltage the resistor needs to be replaced with one of a higher value.

A value of 1.5K is generally still safe, and should increase voltage from 0.65 to 0.7. If you want to go higher, you can try 2.2K or maybe even 3.3K if you feel lucky.

Of course, as punin said, this will void your warranty, and may break your card. Keep a close eye on the regulator temperature. Also, the resistor is in a somewhat tricky position to desolder, and you risk getting tin on the pins of the regulator.

The resistor should be 0603 size to fit properly on the pad. Also, I recommend a 1% type with low temperature coefficient. Resistors with high positive temperature coefficient may cause thermal runaway: as the resistor heats up, the voltage increases, causing the resistor to heat up even more.



Note: if you accidentally mess up the capacitor next to the resistor (C10F), and you wish to replace it, use 1nF, 50V, X7R type. Similarly, resistor R02F is 10k, 1%.
143  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 07, 2013, 10:16:23 AM
So is there any advantage to mounting all the caps to the backside of the board so that a heatsink can be bolted down to the topside of those chips, or does the centre pad provide enough heat transfer through the board to make PCB back-side cooling better?
These chips are designed to dissipate heat through the ground pad and to the bottom of the board. In practice, cooling the board works well enough.

144  Economy / Service Announcements / Re: [ANN] Bitfury ASIC sales in EU and Europe on: September 07, 2013, 07:22:13 AM
Use pencil mod on R2F, make it around 1.1 - 1.2K, voltage goes from 0.66V to 0.81V. The default value is ~1.3K. It may blow the 30AFuse if you go too high; so make sure you do it only if you have a soldering station handy Wink
What is "pencil mod" ?

Note there's no 30A fuse, and it doesn't blow. There's a resettable polyfuse in the 12A supply. If there's too much current, it will get hot, and as it gets hot the resistance increases, which will reduce current. It is resettable, which means that after removing power and letting it cool down, it will restore itself. There's no need to replace it.

Unfortunately, these polyfuses aren't particularly accurate or fast. Don't depend on them to save your board. Their purpose is to protect your power supply from blatant shorts on the H-CARD.
145  Bitcoin / Hardware / Re: [ANN] US/North American Bitfury sales now open ***full prototype pics*** on: September 06, 2013, 06:24:37 PM
Maybe somebody replaced a resistor and increased the regulator voltage. I don't think there are regulators in the same shape that have higher current capability.
146  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 06, 2013, 05:14:07 PM
What is Toch? Didn't see anything like that mentioned in the chip pinout, not sure if I'm missing something for the SPI connections?
"Toch?" is Dutch for "Right?"

147  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 06, 2013, 02:33:20 PM
0603 size has a somewhat higher inductance, so it may not perform as well as 0402. Whether that's significant, I don't know.

Soldering 0402 has one advantage though: after you pick and place 10000 of them, suddenly 0603 seem as huge as bricks.
148  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 06, 2013, 02:11:25 PM
Right. You can't have too much overkill.
149  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 06, 2013, 08:19:44 AM
Maybe add a solder jumper from INCLK to GND.

As far as calculating bypass caps, to do a proper job you need to know the layout of the board and the exact specifications of the capacitor. As they say: "ain't nobody got time for that!"
150  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 05, 2013, 09:13:55 PM
I can't help wondering though, has anyone had success with fewer, larger caps? From what I can see, all the grounds are on the centre pad, all the pins on 3-sides are commoned internally to VDD, then split out to dozens of tiny caps, via'ed down to the ground plane. Does this have some inductance or ESR benefit, are the caps just cheaper, or is this just a design that works, so why mess with it?

More little caps in parallel have lower inductance than a few big ones. Maybe 15 caps is overkill, but it works, so why mess with it ?

I could try mounting fewer, but the problem is that if it doesn't work properly, I'd have to hand solder the rest, which is a terrible job.
151  Economy / Service Announcements / Re: [ANN] Bitfury ASIC sales in EU and Europe on: September 05, 2013, 04:28:59 PM
I agree, the solder jumper will surely cause problems.
152  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 05, 2013, 03:41:31 PM
You do that by hand?Huh??
how long does it take? flippin` ek. I could not do that
Yes, but only for small series, like one or two prototypes. This is a board for Foofighter to help fit a case for it.

I also made these boards (in Dave's first post) in a similar way.
153  Economy / Service Announcements / Re: [ANN] Bitfury ASIC sales in EU and Europe on: September 05, 2013, 03:28:46 PM
Half of the chips, 7-16, are dead and go to zero with auto-tuning while not hashing with manual tuning.
Since the SPI signals form a long chain from chip to chip, there's probably a problem at chip 6 or 7. Check those extra carefully on the board. Note: the chips are numbered in white ink in the same order as in the software.

If the chips are mounted correctly, and one is broken, it could be that it prevents communication with next one in the chain. In that case, the chip could be removed, and the solder jumpers shorted. Beware: don't attempt to fix unless you've done stuff like this before.
154  Economy / Service Announcements / Re: [ANN] Bitfury ASIC sales in EU and Europe on: September 05, 2013, 03:24:27 PM
Chip 4F has a blob of semi-transparent material on one side, on I/O pins
That's flux residue from somebody fixing a short with soldering iron.

155  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 05, 2013, 03:13:08 PM
Here's a couple of photo's I took while assembling an S-HASH board.

156  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 04, 2013, 05:57:52 PM
No, 0.25A is not right.

I just measured it on the S-HASH board by putting a 1Ω resistor on the output of the 1.8V regulator. Voltage drop was 95mV, so current is 95mA for 16 chips, or about 6mA per chip, which sounds a lot better.
157  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 04, 2013, 03:24:41 PM
You get that binner spun yet?   I'd love your layout if you're interested in making it public Smiley
The PCB should be ready in a few days.
158  Bitcoin / Hardware / Re: [ANN] Bitfury is looking for alpha-testers of first chips! FREE MONEY HERE! on: September 04, 2013, 04:25:13 AM
The internal clock has some jitter, which reduces the setup/hold windows inside the chip. Theoretically, with a stable external clock you should be able to go a little bit faster. But is it worth the effort ? The internal clock has an advantage that you can tune it per chip.
159  Bitcoin / Mining software (miners) / Re: Unified miners communication protocol on: September 04, 2013, 04:19:26 AM
Example: You have 500 BF chips and you are given a single work (be it with MTime 300), but don't have nonce range division (HW limitation) and don't have NeedWork implemented. When you start you wait 1.2sec (with 200 chips idle), before sending nonces back. MS sees them coming fast and sends more, but still for 300 + a bit more until your full hashrate is reached.
So the first 5 seconds you run at half speed. Not a big deal over the lifetime of the equipment. And with 500 BF chips, you should have a better solution than running getwork to a single host anyway.
160  Bitcoin / Mining software (miners) / Re: Unified miners communication protocol on: September 03, 2013, 07:30:52 PM
How is the number of jobs it needs calculated then? I mean when we have just started and discovered X unknown devices from unknown manufacturer (otherwise we just won't ask)
If you notice that returned timestamps are increasing too fast, send work faster.
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