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Crud. Well I can fix blown ones for .1btc. Haven't had a return yet, remember though it's probably a blown Rpi that causes the BB to blow.
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You know Britain saved Europe from Germany in World war I, they saved it again from hitler, the German chancellor, in World war II, and now they are saving it from another German Chancellor by Brexit.
We're getting fed up with it, please can the European countries wake up to what is going on, and not rely on us saving them if they do it again.
Sort of. Technically it was the arrival of fresh US troops that really tipped the scales in WW1. In that the US was the group who saved Europe from the Kaiser. In WWII, the US didn't do dick compared to the real hero: The Soviet Union. They took a hell of a beating to be honest, and really did the heaviest lifting in WWII. Thus we should give credit where it is due. |
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This will be interesting to watch. Fortunately we can still do business with people in the UK, no problem. Just pay in bitcoin.
Bitcoin solves all sorts of problems.
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Ok, two boards shipped, back to thinking here. It looks like it will take forever to get my micro drill bits (under 1mm sizes) does anyone know of a source that is not in China with a 2 month ship time?
I'd like to try drilling a board to see if I can clear the faults.
In the meantime I have one extra KNC controller board that I fixed as a spare, just the board not the bridge/pi or BBone. 3btc if interested
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Ok, Steve's cube is in a stable state. Hashing at 50mh (not megahertz, megahash). Not bad for a total dud.
Here's the scoop:
Die 0 is working, as is Die 3.
Die 1 is bad. Specifically power supply 2 blew up and took out the die and was nailing the spi bus. That was the nature of the problem. Removed.
Power supply 3 is ok, however there is nothing for it to power, so it is down.
Die 2 is interesting. Power supply 5 was also bad, pulled it and supply 4 is powering the die at 50%. So you can run it at 150mhz, with the other two at 300mhz (well, 325 depending on your inside temps).
That's about as far as I am going to go on this one. I could try to sweat another supply on for supply 5 but my record of success is to put it politely "low" on those and I have no new supplies here. So 50mh cube it is, better than a 0 mhz cube. :-)
One other thing I verified is a failure in the Z17R chip there will show the symptoms of a working cube with supplies that come up but never hash. Interesting. Need to find what those two chips are.
DC/DC Voltage (V) Current (A) Power (W) Temperature (°C)
0 0.7833 40.1875 31.479 80.500
1 0.7787 40.1250 31.245 87.400
3 0.0046 0 0.000 36.600
4 0.7848 38.3750 30.117 57.700
6 0.7784 42.0000 32.693 64.100
7 0.7811 42.0000 32.806 70.400
KNC 0: | 50.89/49.78/49.97Mh/s | A:20 R:0+0(none) HW:2/.22%
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Nope. Predictit has a 10% chance. When people risk real money the results tend to be better.
Edit: The next 10 to 15 hours are CRITICAL!
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In the meantime I figured out Steve's cube: The problem is subtle: One of the power supplies has a defect and was putting 12v on the SPI bus. This blew out the U19 chip (WHAT IS THAT THING!) so I swapped it with a spare, removed four supplies to find at least one dud, and now it's hashing away at 30+mh. Not bad.
This does also point out that U19 is one of the key parts of the chip side and not the supply side. I wonder again if these components are blowing which takes out the whole board. Hm....
C
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Something I did in my older mining days: I would put the units on a windowsill so the hot air exhausted *outside*. Acted as a nice whole-house fan in the summer, and kept the room at ambient temps overall.
These days I'm not in the mining business, although I wish I had bought a Titan. I just fix em. :-)
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Well it's not the level converters. Oddly enough it looks more like 1.8 volts being placed on the SCL bus. Odd.
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No prob, based on the lack of any sort of heat damage, arcing to the power connectors, or any general screwage I'd chalk it up to factory bad components.
The fun question: Which component.
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Your Titan board is a different class of problem: What is happening isn't a traditional short in any sense of the word, it's more like the board has gone insane and is chattering all over the place on the SPI bus.
This doesn't happen when the board is powered down on the 12 volt side, which indicates that the problem is not in the LM75 or EEProm chips. Likewise there is no direct short from the +12 line into the SPI bus or the SPI power bus either. Nor are there any identifiable shorts from the supplies into the board.
When powered up the SPI bus to all cubes "freezes" with gibberish.
Did this board ever work, or was it dead from the factory? I see no evidence so far that any of the supplies have failed, but it might be an internal error.
C
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Not sure. Note I can repair the bridge boards for about .1btc (why not...) but you also probably have to replace the Rpi as that is what blows up in the first place.
Also I have a pair of repaired controller boards (just the baseboards) here that I'd be happy to sell for .3btc each. New FPGAs, both tested and running fine. Six plug units.
Can help fund the "buy drill bits" repair fund :-)
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Ok, back to the drawing board. I now have a dremel 4000, I can't use the jeweler's gravers because the board is way too big to fit in the staking tool. Oh well. So what's left?
We know the chip/die is shorted internally.
We know KNC bussed the connections internally to the board (fuck).
We know the vias are 1mm in size.
So I'll go in deeper and order two key items:
1) Drill press for dremel tool. Not as good as the staking tool but should get me there.
2) Some micro-bits for drilling pcb's.
If I can't use the dremel I'll use the big drill press. Goal will be to drill out the vias on the shorted chip side.
Unless I can get a massive bga stencil, this is the only idea I've got :-)
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Update in the not-so-good news category:
I picked up a high power dremel tool and a milling bit in order to finally isolate the die hotel power line that gets shorted from the rest of the dies. This should be do-able by cutting the double and one single traces from the capacitors under the board to the vias for the pads into the chip. Very tough to do with a knife because of the rather thick copper foil used on the board.
However a mill bit will work. Cut the traces checked the resistance, still zero. Checked a blank board to see what the resistance is, it's zero as well, which means those lines are common on the board and can't be separated out.
Why oh why did they do this? It really makes no sense in the world, but it means in practice that there's no way to isolate that power supply line from the rest of the dies. Which means boards that die with shorted pin 4 or 6 are dead.
Drat. Ok, back to the drawing board. Anyone know if I can buy the schematics for these boards from the bankrupt entity that is KNC? I'll offer them a litecoin.... :-)
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Another question I have is can I replace my PCIE plastic power connector by just plugging in a new piece over top the existing pins? I pulled off the plastic PCIE ports on 1 cube leaving the metal pins behind. I found some new PCIE plastic ports online that do not have the pins embedded into them. So can I just plug these new pieces on to the old pins and be back to BAU? I haven't received the PCIE male ports yet. But it took me a long time to find the part without the pins embedded into them. So I am hoping this works, without going through the whole solder process.
I suppose. Just make sure they are clean, be gentle with the pins, and slow down a bit. The real nightmare is when you overheat the pins to the point where it breaks the connections inside the board. We can fix that.... :-) Damn, litecoin is doing well these days. Amazing the value these Titans provide.... |
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No shortage of hash powr (the .7v) down there either.
What does this mean? Is it bad idea to under volt the dies? I thought it was good thing to do, less electricity and less heat. No I was talking about the fact that the units had enough power planes going to the dies without having to run huge amounts of low voltage electricity across the board. Undervolting is fine, but lower voltage to maintain the same hash rate requires higher current. C |
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Oh that's NEAT! What happened here is you lost a supply on die 4, most likely due to running it hard. However you didn't short the high side FETs, that's nice.
Now when you lose a die you can still run on one supply but only at half speed, say 150mhz for a 300mhz die. The die will hash at 150 happily and the supply will max out at around 40a. But you have it running at 225mhz which is impossible. Except that ohm's law is I=E/R, and if you boost the voltage you can run with less current. So running at 30% higher voltage allows you to run the die at a higher clock while pulling less current through the one remaining supply.
Darn, never thought of that. Weird as hell, but why not. Technically the limit is the Molex plug and since you're running one die slower (though still pulling a lot of power) you may be ok. I would not screw with it, run like hell... :-)
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That is why my #1,2,3 recommendation to all titan owners is to slow the hell down a bit. Enjoy the money coming in, don't burn the goose because this might be around for awhile.
Yeah, dial those clocks down to 225 so I can get more ~LOL~ Repair prices are the same, regardless of the... actions of the user. However especially funny ones will be posted. |
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Rosin core solder. I would highly recommend alloying the solder or using chip-quick to get the old ports off, the high temp ROHS solder used coupled with a lack of preheating coupled with the massive heat sink of the +12 and ground planes will make removal complex otherwise. Only one socket. Older boards like Jupiters and some Neptunes had two pads. Run it at 60-70mh tops. Don't go for 80 and you won't break the board so much. C New Titan owner here - so please forgive if any of my questions are completely stupid. I have two cubes with pretty coloured pci-E connectors (can't decide if this is still dark yellow or already brown  ) and I would like to replace them. I have found the following part from Digikey and am wondering if that's the right connector or if there is a better one from DK or some other electronics warehouse: WM1353-NDIs it recommended to use some special solder for the pci-E connectors (i.e. lead-free with higher temperature) or can I take the my preferred day-to-day leaded solder? Speaking of pci-E connectors, I have read rumours here that there is a second one on the PCB but not populated. Since I haven't opened any of the cubes I wonder if somebody can tell me if that second connector exists and simply can be populated and used to circumvent the single pci-E bottleneck? Since I have to take the whole thing apart to replace the pci-E connector, I would also like to add the DCDC heatsinks from this video. Does anybody know where to get these? As I have to re-apply the thermal grease and need to order that too: What thermal conductivity should it have at minimum? And any estimates on how many gram per cube I will need? And finally: Is there a good source for 16AWG Y-splitters or do you guys make these all yourself? I realize the Mini-Fit connectors from Molex are only rated for 18-24AWG but I guess squeezing two 16AWG into such a crimp pin is just a question of enthusiasm - or are there better rated crimp pins than these: WM2501CT-NDWM2500CT-NDThanks for any tips, hints and links in advance. |
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Chips would be the key. To be honest their implosion power design and using off the shelf supplies with brains was probably one of the best ideas ever. Those supplies aren't that bad.
Likewise their carrier chip is not a bad idea: It's rigid enough to hold the dies well, and with a proper heat sink on the top and non-insane overclocking it drops the heat pretty well out of the top of the die. No shortage of hash powr (the .7v) down there either.
They just cheaped the hell out on the clocks, sensors, and supporting circuitry. I would love to see a nice temp probe in the center of that chip, or one in the center and one at each edge. That would allow control and a safe power down of the chip if the temp spikes.
But I would never design a miner. They all have a life span measured in months, and to be honest if you only have to have it survive 6 months designing anything better is a total waste of money. If you slow it down a bit to save parts, people will buy someone else's chinese rocket crap. Fair enough. The Titans are probably the first and only miner that has lasted for well over a year now and is still profitable. How could they have known that every other Scrypt maker would go tits up?
That is why my #1,2,3 recommendation to all titan owners is to slow the hell down a bit. Enjoy the money coming in, don't burn the goose because this might be around for awhile.
C
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