ok so because i believe in sharing info with others especially with mining hardware makers that take little to no time to help users out after they fork out thousands and thousands of dollars i have decided to post some info here for the community and hope it helps some people out.
brief back story:
i purchased a terraminer from a seller on ebay that ran at only 700gh/s for about $500 and paid in btc. the seller was an awesome dude and got that beast sent out and packed very well. he showed pics of the miner both inside and out and there were no char marks on the boards. the psus were green so no board shorts in this miners case but i m working on boards that have those issues and will post that info as well if i get some extra free time when im finished fixing them.
problem #1 - the first thing to check when only one board is detected is the little black usb dual port hub they used in these machines. Now i have never ever seen this issue in all the years i have been doing pc/laptop component repairs so this kinda shocked me but when i was swapping the usb cables from one board to the next i noticed only one cable was able to talk to the beaglebone at a time. i assumed it was a cable defect even though there were no signs of cable damage. since these miners r hard to move around in even with all the extra room (weird....i know but if you have to hook and unhook the power cables to the boards as many times as i have your fingers get very very sore) i didnt remove the hub which i should have because it would have saved me troubleshooting time. one of the pins on the bottom usb slot was completely burned away. im not sure y this happened since i thought these got power from the psu and not from the usb hub but after taking it out and removing the housing cover from the actual usb board i saw the white electronic smoke marks on the corner of the case in the same place the burned up pin is located. now when i say burned up pin i mean gone....not charred or singed i mean there was a pin there but now there is no pin there at all so swapping the usb hub out was a pain because i had to unhook everything again but once i changed it both boards were detected. on to problem #2!
Problem #2 - the miner was detecting both boards and hashed away at much lower speeds then i had hoped on the second board so i pulled it out and saw the tell tail raised dots on a few mosfets. I immediately said awwwwww shitttttttt cause the codes printed on the top of chips doesnt always lead you to the component you need and cointerra wasnt gonna tell me shizz as usual so i gave the code a quick search and sure enough the one printed wasnt the full product number but luckily there was only one item with this number so the extra part of the code that was left off of the chip doesnt matter because that product family only has one version in it so no worries about getting one that is too low a spec or even too high. luckily digikey (awesome company) has these bad boys in stock and ready to go so i picked up some of them. here is the link:
http://www.digikey.com/product-detail/en/CSD16342Q5A/296-30314-2-ND/3074512i had to pull out the bad ass ir station to replace them because these boards just suck the heat out of one spot so the smaller machine wouldnt get to the melting point of the solder no matter how long i waited but after swapping those out the board was running at 700gh/s just like the other one. now ik some are saying "but they should run at 800gh/s" but i paid $500 and resolved the issue and now get over 80% of the power out of both boards so beggers cant be choosers and risking damage from heating and cooling the boards to replace other chips wasnt worth another 100gh/s or risking losing more gh/s by mistakes on my part....im only human and like eveyone else i make mistakes so it wasnt worth it to me. 1.4th/s vs 1.6th/s was more then fine given the price i paid.
Problem #3 - the psu's ran pretty hot. this annoyed me even though they run fine. to resolve this i did a couple of things. first i opened the psu's up to see which was the fan was facing. i found out my psu's sucked air in from the back instead of blowing air out of the back which i would have expected it to do. so to get to step 2 i had to swap the airflow 180 degrees. to do this i remove the fan and pushed the 4 rubber holders through the mounting holes so it could be taken off of the plastic mounting plate (sounds confusing but if you look at it you will see what im talking about). once removed i flipped the fan around making sure to keep the fan cable facing the same way and pulled the rubber mounting legs through the fan holes to lock it back to the plastic mounting plate. the fan sticker has to face the back of the PSU (back being the area the power plug connects to). Once i test to make sure it works i put it back together and made sure they could power the mining boards and that nothing bad happened lol. **NOTE** im not responsible for ignorance. If you cant do this or havent opened things like psu's or computers before then proceed at your own risk and you risk being hurt big time from the caps in PSU's so please be smart.....pay attention to what you touch and dont rush things. On to #4!
Problem #4 - now that the psu fans are in the right direction i thought maybe i want huge airflow blowing into them to keep them ice cold soooooo thats what i did. I have some old delta fans that were installed in podiums to keep air flowing into the area where PC's were installed at a campus. these plug into the wall and run on 110v power so no special wiring needed and they move alot of air through their blades and dont sound like delta computer fans that resemble the noises plains make when taking off. they arent silent but they dont compare to the fans in the front and back of the miner already so ya it wont add any noise to your setup. i put the fan on the side after drilling a few holes because the fan is a little smaller so the original holes dont line up....they come close but if i had another inch i could have used them but i didnt so i just drilled some fresh ones no problem. the fan blows air into the hole which is why the psu fans needed to be set to blow air out of them and now into the same place the delta fan is blowing air because the delta fan will win killing the internal psu fan because of the pressure created. some may not care about psu temp but when i took the psus out after running an hour long test they were hot to the touch for a long time after they were in use which will slowly kill the machine. a cold machine is a happy machine. even though i paid little for the miner i didnt want to run it until it died.....i work on olectronics for a living....ik if you treat things right and take care of your stuff they will pay you back in the long run. and its always better to prevent issues then it is to scramble around waiting for stuff to come to resolve the problems your having.
problem #5 - the power cables. this goes without saying im sure but what the fuck was cointerra thinking when they decided to use utility power cables to power these miners?? they put extreme amounts of preasure on the terminal ports on bother the psu and the miner boards. i had one board that had the connector ripped off. sure they may be sturdy when mounted on the boards but the power cables have no give in them what so ever and will not sit perfectly and after tearing my fingers up trying to get them on and off the boards to test i finally said "fuck it" and went back to my car audio installation days and grabbed some 0 guage amp wire. this shit can handle 250a or 3500w per cable and thats for the entire length of a car which isnt whats needed here so if it can provide stable power to 2x jl audio 1000.1 amps which are powering 2x jl audio w7 13.5 subs then this can surely handle some wimpy miners and sure nuff (ik its enough) i was right lol. not only can it handle more then the entire miner puts out but its extremely soft and flexible unlike the cointerra psu cables. they will need to be zippe tied to keep them out of the way of the fan or laid down along the bottom of the case or whatever you choose to do but no matter the choice one thing is clear....im glad i "voided" my warranty by making these changes. I no longer have to wonder if my psus are gonna die from running hot or if i will rip off a post from the board. if they die i know it wasnt from heat or non flex power cables!
sorry guys for makin u read my essay. i try being as detailed as i can when explaining things like this and i hope it all makes sense but most of all i hope it helps someone out with a miner they are having issues with. just know if both of your hashing bards have the lights cycling through the bottom of the board it could be something as simple as a burned up usb hub port and most wouldnt think to look there....i know i sure as hell didnt but im glad i did even though i feel silly for not doin it before lol.
p.s. DO NOT FLIP THE POWER CABLES ON YOUR MINER UNLESS YOU FLIP THEM ON THE PSU TO MATCH WHAT YOU DID ON THE BOARDS. POS SHOULD NEVER BE HOOKED TO NEG. THATS JUST COMMON SENSE. EVEN IF YOUR DESPERATE DONT DO IT GUYS! I CANT BELIEVE SOME HAVE TRIED BUT I HOPE THIS STOPS OTHERS FROM ATTEMPTING IT. NOT EVERY MINER USES THE RED CABLE FOR POS AND BLACK FOR NEG BUT IF YOU PAY ATTENTION YOU WILL SEE EVEN THOUGH THE CABLE COLORS ARE NOT THE SAME THE WAY THEY ARE HOOKED UP IS. FOR EXAMPLE IF YOU HAVE A MINER THAT HAS THE RED CABLE ON THE NEG TERMINAL LOOK AT THE PSU....YOU WILL SEE THE RED CABLE IS ON THE NEG TERMINAL OF THE PSU TOO. THE COLOR DOESNT MEAN IS POS OR NEG....ITS HOW ITS HOOKED UP TO THE SYSTEM. I COULD HAVE USED YELLOW FOR NEG IS I WANTED TO. IT WOULD CONFUSE OTHERS AND I AGREE THEY SHOULD HAVE FOLLOWED THE TYPICAL COLOR USAGE PATTERNS THAT ARE A STANDARD THROUGHOUT THE ENTIRE WORLD PRETTY MUCH BUT THEY DIDNT. MAYBE THEY DID IT TO CATCH MINERS OFF GUARD SO THEY FRY THEIR BOARDS CAUSING MANY TO PAY $350 JUST TO HAVE THEIR BOARDS LOOKED AT....I DONT KNOW....WHAT I DO KNOW IS IF YOU SWITCH THE POLARITY YOUR GONNA SCREW YOUR SHIT UP AND PEOPLE TELLING YOU OTHERWISE SHOULD BE IGNORED.....EVEN IF THEY ARE RIGHT IGNORE THEM.....IK I WOULD NEVER TEST THEIR THEORIES OUT EVEN IF IT WAS PROVEN TO BE TRUE BECAUSE IT GOES AGAINST EVERYTHING I HAVE LEARNED OVER THE YEARS ABOUT THIS SHIZZ. ITS OK TO BE A JEW AND NOT SPEND MONEY TO HAVE SOMETHING LOOKED AT BUT THERES NO EXCUSE FOR STUPIDITY SO YOU HAVE BEEN WARNED.