Sadly, i cant get my 2x 6950 system to run at all on cgminer. I've tried numerous versions of cgminer from 2.5 to 3.5 and all of them crash except 2.7.7 in which it tells me this:

http://i85.photobucket.com/albums/k62/rusolinio/miner1.jpg

My config files contents are:
cgminer --scrypt -o stratum+tcp://global.wemineltc.com:3335 -u username -p pass -w 256 -g 1 -I 18

Looks right to me? The miner details are correct and confirmed by another system running cuda miner and 2x780's. Can anyone see whats wrong here? All the other versions of cgminer i have tried hang on startup for a few mins then crashes ala 'cgminer stopped working'.

I am currently using 13.10 catalyst drivers with SDK 2.7 (tried the latest 13.9 drivers and SDK 2.9 = no luck).

Does any kind soul have any idea where i could even begin to start to look for the issue? Brain is frazzled and i would seriously appreciate any help anyone at all may offer.

For now, i have to stick with the 2x780's and the almighty speed of 560kh/s they produce. 

As a total newb, I damn nearly pulled my hair out with this thing but I eventually got it to work with my 2x780 EVGA FTW's. I poured over this entire thread TWICE to find a config that worked and NOTHING WORKED until I came across someone who posted this extension:

 -H 1 -l K48x6 -C 2

That worked great, but only one card functioned and with weird lag issues. That all went away after disabling SLI and adding:

 -d1,0

It did an autotune for the second card but then both fired into life! YAAAAAY I didn't just waste FOUR HOURS!!!! I'm so happy! Currently hashing away at a combined speed of 620kh/s. If anyone has any other suggestions to tweak these bad boys, i'd be super grateful to hear it. Anyway, just thought I would share my findings.

EDIT: Dropped to 560kh/s now. The next mission: MORE POWWWWEEERRRRR!

Order: 27xx
Ordered and Paid: June 05. Cancelled order and refunded Within 5 days of asking.
Ship to: IRE
1 Mercury
Estimated shipping date: None.

Page 6 of this very thread, at the bottom.

Anyone here asked for a refund on a knc miner? If so, did you get your money back in a timely manner?

Why would a block erupter be killed when being supplied by correct voltage?.... Not sure what you mean here.

Got bored, so i knocked up a crude drawing of a cooling/power solution. Its not to accurate scale, but you get the idea. Thoughts?

http://i85.photobucket.com/albums/k62/rusolinio/miner31.jpg
http://i85.photobucket.com/albums/k62/rusolinio/miner21.jpg
http://i85.photobucket.com/albums/k62/rusolinio/miner11.jpg

Cool project, but too pricey.

I'd pay 0.75 for one to dig the mud out my walking boots? Waddya say?

A drug addict in front of a mcdonalds ranting on about how silk road ruined his life. I came home, googled silk road, had my brain in bits for days thinking about how payments are made, then BAM....bitcoin was revealed to me. Silk road isnt my thing personally, but the way BTC seemed to enable its existence just grabbed my interest and wouldn't let go.

I have the TXCO variety 3.3v in 5x3.22mm. 14.38, 16, and 18mhz.

Thanks for the info, bluestreak. I thankyou also for your work on this overclocking business.

I have a good plan for cooling and setup of several miners together so once i get my rework gun, i'll post pics of what i make.

I have done that. Theres seems to be a lot of varying methods/techniques to do the job. I wanted to know from those that have completed a successful crystal change the best method for changing them out on these miners as the location of the crystal is very close to two capacitors at the left of the crystal itself (plastic tweezers?). I wished to know the right amount of heat to apply in case i ended up damaging components.

How are you now powering the usb miner? I believe that using a 16mhz crystal will require more power, hence you not being able to use it in a usb port anymore. You will have to hook it up (via the pads on the end of the miner board) to a pc power supply (or similar) equivalent that has a proper 5V connection with a decent amount of amps.

Did you change both R1 and R2 resistors?

Also, any detailed info you may give about the best way to desolder and solder the new crystals and resistors in would be hugely appreciated. What i really need to know is how much heat can these little crystals take?

In regards to powering these things, i was planning to solder a molex plug on the back end of the usb miner so i could simply plug them in and out of a standard pc power supply. Then, for the data, use usb extensions with the power line cut. Hopefully, using that method would allow quite a few overclocked miners at the same time.

Of course, i'm thinking out loud here so if anyone see any trouble with that, please let us know.

*In my finest new yorker accented female voice* ..."Certainly"

https://www.youtube.com/watch?v=IgrEbJN8dcQ
https://www.youtube.com/watch?v=0XENpPtisnM

Interestingly enough, you can solder the crystal with a normal iron. Its a wee bit crowded on the erupters, but you could probably do it with a really small tip like this guy:

https://www.youtube.com/watch?v=0XENpPtisnM

Ditto. Just waiting on hot air kit and some teeny tiny 1.5mm and 1mm hot air gun nozzles for the rework. If you bought one of the ebay cheapo kits like i did, you're gonna need smaller nozzle tips. After watching one or two vids on youtube, i'm now an instant expert.....haha.

Oh man, this thread is fantastic. Great work guys.

I have some experience in soldering, but very little in smt and those crystals look to be very tightly packed in there. Is it better to use a hot air solution to solder them in?

Also, i'm now wondering about power modding hubs so that they can handle several of the overclocked miners, plugged in as they were intended. Still thinking about cooling and such, but i cant help feeling i want to build something water cooled. Perhaps using something like these:

http://tinyurl.com/mvytnq4
http://tinyurl.com/m3g9m9n

Anyway, keep up the great work fellas. The thought of building an overclocked usb miner rig will now dominate my every thought.