Fixing and hacking KNC Titans and MAT miners because they break from time to time

Hi everyone!! I’m Lightfoot from the bitcointalk forums and I just realized this site is here, so I figured I would start a thread with my research findings on the Titans and put a post for people who need their KNC Titans fixed.

Currently I can repair the following issues:

  • Blown bridgeboards for KNC Titans
  • Blown power connectors on Titan cubes
  • Incinerated power connectors on Titan cubes
  • Cubes that short out the 12 volt power supply
  • Cubes that shoot fire out the back of them
  • (These usually wind up shorting out the 12v supply)
  • If your Titan has one die, I can try to get it to 3-4 dies
  • If your Titan comes up with no hashing but can be seen in KNCminer, I can fix it
  • If your bridgeboard is dead, I can fix it but you have to replace your Rpi too.
  • If your Rpi is dead, just get a new one and power it via the USB port. Lazy but works.
  • If you can’t find an RPi I can make Titans mine on Neptune controllers with BBB’s
  • Any and all controller problems (reboot, etc)
  • Little displays that don’t display anymore (sometimes)
  • Can even fix/unstick MAT miner controllers. And A6’s but that’s bitcoin. :slight_smile:

The parent thread with 30+ pages of findings, documentation, and such is at:

Anyway if you need help, let me know. With the run up in litecoin prices these things still seem to have value, which is nice. I accept payment in litecoin and bitcoin.



Reserved for technical notes:

  1. I have managed to port the KNC code for the Titan to the Beaglebone. The link is over at Bitcointalk, free download, just donate something or mine to my address for a week as thanks. This was a bitch on wheels to get working.

  2. If fire is pouring out of your miner like molten lava through a jungle village you might have run the DC-DC supplies a bit too hot and set fire to the capacitors. Replace them with 22-24uf caps and try to keep the DC-DC temps below 60c or so. Given the lack of airflow over them and that weird-ass insulated blanket thing on top of them, that would be a good idea.

I can fix this.

  1. I’ve been able to get many blown boards up to what I would consider to be full power (600gh, <300 watts) not too bad. Do have to trim a bit since one of the power supplies runs a tad bit hotter, and the other unit is currently cooled by a water block. Weird.

  2. If you’re nutty enough to overvolt/overclock your Neptune or Titan here is a very important tip: NEVER MOVE IT WHILE RUNNING OR HOT. Power it off, wait 15 minutes for it to cool, then move it around. Why? Because the chip can get so hot it is softening the solder underneath it. Moving it with that huge heat sink can squish the solder into short-ville. Bye bye unit.

  3. Never plug or unplug the molex thing from a running power supply. Always power off the supply then plug it in or unplug it. Why? Because all the caps on the power supplies will cause a powered molex to SPARK and damage the plug. Then it overheats and you feel the burn… If you see your molex plug is discolored, has burned pins, or is a charred hunk of wreckage, drop me a line:

I can fix this.

  1. If you have blown Neptunes or Titans and want me to look at them, let me know. Getting pretty good at this, I can now fix shorted Titans and Neptunes that don’t talk to the controller. Rates are reasonable in bitcoin :slight_smile:

  2. If you think your beaglebone is screwed, check the bottom of the board while powering on. The left LED should come on then the right LEDs should flash in a nice little show. No right lights, no booting. If they don’t boot try re-installing the KNC firmware. If that doesn’t work reflash it with a stock debian build then re-install the KNC firmware.

I can fix this.

Cool I did have one BB that would not come up but made a high pitched whine on power up. Turns out putting a micro-SD card cleared this and allowed boot. Turns out DPO (dreaded previous owner) must have picked up the board and pressed down on the SD interface pins, bending one to short power to ground. Don’t do that :slight_smile:

  1. Both Titans and Neptunes seem to have “islands of stability” in terms of frequency and voltage. For example 350/450/450/450 at -.3v will yield a solid 600gh, but backing down to a 200/450/450/450 will cause the first pair of supplies to stop putting in current. Weird, but happens on several cubes and several controllers so this is not a fluke.

Run your Titans at 250mhz per die max. Really, the diff between 60 and 80mh is where the death zone is.

  1. Never unplug the 10 pin connector from the controller or cube while power is applied. Always shut everything down. When plugging in the cables make sure they are on top of all 10 pins in the Titan and oriented properly. Doing this wrong blows up the cube and controller and yes, I can fix this

  2. Always be careful when plugging in the 10 pin cable. Do it with the miner off, and make sure the connector is seated on all 10 pins, it’s easy to only get 5 of them and it blows up the miner and controller (which I can fix.)

More to come. Donations of parts and junk welcome.


Hey can you check out my thread ? i was asking for help with a titan rebooting itself constantly every few minutes but it does not completely reboot but only the miners so it goes from 250-300 mh’s to 0mhs and then is stable for a few minutes, you can see pictures of my settings in my thread, okay thanks

I replied in private. Pull all the miners off the controller, see if it reboots. If it does, bad controller send in. If it doesn’t add cubes one at a time and see if it reboots. if it does that cube is bad send it in.


Hey lightfoot, you sold me a replacement Titan board last year, still going strong :slight_smile:

I can vouch for this guy.

Nice to see you here buddy

Sweet, glad it’s still running along.

Side thought: One trick to keeping Titan and Neptune controllers out of the shop is to never unplug the cubes from the controller or plug them in while the power is on.

Meantime got another two cubes fixed for a customer, these had the unusual only a few power supplies showing in the web interface, hashing with errors on one die (you can see the errors if you ssh in as username pi then run screen -r)

Boards turned out to have been cooked, black spots on the back of the board under the dies. Reheating the chips and unbending the boards got all four dies running on one Titan, three out of four at full speed on the other. Now they are both happily hashing away at 135mh between the two with temps of 42c on the chips and the 60’s on the supplies.

I seem to be having pretty good track record fixing the roasted boards. You can prevent this by running the board at 200 or so watts indicated (65mh) per cube. That seems to be the sweet spot. Going full blast in a hot room will cook the dies, requiring repairs.

Couple more coming in. Never dull…

And another two repaired, issue was blown drivers on both boards and some taco-ing. Hint, when putting on the heat sink tighten the three screws down enough that the sink does not “slide” on the chip when you try to torque it around a bit. Should sit firmly not wiggle, that’s enough. And get rid of the crap KNC heat sink compound, use something non metalic (I just love cleaning that crap).

If the sink won’t press down enough you have tacoed the board. I’ve found after straightening on the heaters that putting one of those little dopey rubbery heat pads under the front of the board will keep it from tacoing while providing enough give to not break the chip with the pressure. A little tip.

Back to troubleshooting yet another two boards, they are oddballs.

Another two titans, exceptionally badly burned power plugs. Fortunately I was able to get them off and new ones on. Back to full hashing and back to the sender.

A note: These both had the original thermal paste, and I got a chance to see it in action: It’s like a rock, which is why as long as the cube isn’t disturbed it can provide thermal connection to the dies. But if that heat sink moves the thermal paste shatters like ceramic, and you have little heat transfer. Likewise the lids put some down pressure on the heat sink, so always run them with the lids on.

Also: One of the heat sinks had copper pipes at the bottom that were not coplanar. In order words one of the tubes was lower than the other three, that would cause wicked overheating. Threw it out and used one of my neptune spares, but remember to check that; the bottom of the heat sink has to be perfectly flat.

Back to work on some controllers.

Lightfoot, you seem to be the answer to my prayers!

I’ve got at least 10 Titan cubes which are running in varying states 1-3 dies working on each and an additional one with a short, that I would love to have working as best they can.

Please can you get in touch so we can discuss.

Many thanks and keep up the good work!!!

Sure. In a nutshell if they have only one or two dies hashing they are worth fixing. Likewise the shorted cube (I assume it shorts the 12volt supply when plugged in, correct) can also probably be repaired. If the cube has 3 working dies then I would say just run it at full blast 325mhz on the 3 dies; that is over 60mh, going faster could damage the cube.

Do you know how to take the cube apart, remove the heat sink, and re-apply heat sink compound to re-assemble? If so you can just send me the boards.

I’ll send you the shipping address in a PM.

Let me know the USPS tracking number, how many, and what problems and I will keep an eye out for them.


Thanks a lot Chris for getting in touch. I will reply to your PM and hopefully you can get many of my cubes running again! I really appreciate your prompt reply!!!

my titan is not hashing"Titan comes up with no hashing but can be seen in KNCminer"
but also I can’t get in to the miner I may have forgot password

If you have forgotten the password you would need to reset the configuration. Did you download the manual, I think it’s hold down the button on the side of the board while powering it up will reset the whole config. Or you can download the 2.00 code from KNC’s site and re-flash the miner. Both will reset (don’t forget to apply the 2.02 patch) and get you running again.


thanks I’ll try that tonight

Another 4 cubes done this weekend, more on the way. These were the normal burned plugs; two of them actually had the plugs welded to the board; the guy had to cut the wires to send them to me. Fortunately all fixable, sending them out Tuesday or so.

Note: If you want to replace the PCIe plug yourself PLEASE get some kind of a pre-heater and bring the board up to over 140c before de-soldering and re-soldering. Reason is this: If you just use a really big iron you will burn the traces on the bottom side of the board trying to heat the pin up enough to pull out. Then when you finally rip them out and fit in a new plug your iron will cold-solder the connections inside the board (where the main power and ground planes are) because the iron on the pins will not be enough to warm up the power planes. A cold solder joint will get hot; the new plug will fail, and the inside of the board will be damaged.

Pre-heating the board means the iron has to only heat up 40-50c more in temperature instead of 200c which makes a good solid connection. Important.

Working on nine more boards, these are interesting in that they have big heat sinks on the power supplies and all of them have seriously damaged FETs on the supply boards. My guess is that the extra heat sinking on the chokes shows a cooler temp reading at the controller chip; then the FETs get overloaded from more power till they short.

Interesting failure. But fixable, just takes time with the preheaters and the air tools… 5 are done tonight, 3 more tomorrow (last one turned out to be ok, no charge) then on to the next batch…

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Ah at last. Everything has been fixed and sent out and I can take a bit of a rest. Also managed to fix two wedged MAT controllers.

Down to fiddling with a few dead boards. Pin 6 shorts seem to be the worst, but there are different classes of shorted. Right now I have one with a few hundred ohm short on the bench, not sure why it’s not zero but there you go. If I can fix it I should be able to restore 2-3 of the dies.

Keeps me busy.

it worked thanks again

Mine away dude!