First things first (before installing a x0xlarge)
Chances are you have a lot of nice patterns in your x0xb0x. Back them up first!
n0nx0x2 uses a different format compared to the stock x0xb0x firmware. c0nb0x can be used to export and convert your patterns to the new format. Get it here: http://antonsavov.net/cms/projects/c0nb0x.html (mac version here)
=> Connect => Export EEPROM (.CXM)
Beware, lossy! The conversion later on will be "lossy". While standard firmware will allow you to transpose a note "up" twice, n0nx0x2 follows the strict rules of the 303 sequencer which means you only get one "up". This does not mean the octave range is reduced: patterns can still be transposed as a whole, it just doesn’t allow you to span 4 octaves in a single pattern. It may be that some of your patterns will end up sounding "wrong".
Installation (front panel)
Installation is pretty straight forward, remove the knobs and screws from your x0x. Sometimes the knobs won’t go off easy, in that case, use a soft cloth on your old front panel (to avoid scratching it) and wiggle a large-ish flat head screwdriver underneath the knob. It will go easy with this trick.
Next, remove the front panel and replace with the new one. Re-attach everything in the reverse order. It's simple stuff.
Flat top leds? One thing to note is that you're pretty much screwed if your x0xb0x uses flat top leds. They look nice but they're a very tight fit, congratulations to you if you can pull it off (or rather, put it on!) but of the 2 x0xb0x'es I've worked on that had those kinda leds, after trying all sorts of tricks, I just unsoldered the leds and placed normal ones. It's not worth the frustration.
Installing the cpu is plug and play. Remove the back of the x0x, get out the big cpu chip from the bottom. (Use an IC puller or, gently pry it upwards using 2 flat screwdrivers as a hinge underneath it. Here's a nice user-made installation video if you are wary: http://www.youtube.com/watch?v=hUPOrYAC-2g
CPU is not in a socket? Oh boy.. although this rarely happens (I have never seen it), I can imagine there are people out there unfortunate enough not to have a socketed cpu chip. In that case, you're gonna have to desolder it and get a socket for the x0xlarge. If you are not used to doing this, get someone to do it for you, because desoldering such a big chip doesn't seem like an easy task.
Don't put the screws back in just yet, you may want to tune your x0xb0x later on (this is not required but it's a great opportunity to do so, there's a nice Windows VST for it by antto: http://antonsavov.net/cms/projects/as_x0x_tune.html ). A normal guitar tuner or software tuner application will do too.
N0nx0x introduces a settings menu. It is important you reset them to defaults on first run. Hold FUNCTION+CLEAR while turning it on. After the visual led-show you can release the buttons.
Set the x0x to pattern play to test that everything is working. Note that the positions of the switch have changed drastically. Refer to the manual for more info:
You’re ready to starting using and enjoying this OS.
If you want to restore your old patterns, use c0nb0x again. One thing worth mentioning: you need version v1.01 (windows only). A new version working on both OSX Yosemite and Windows is coming very soon. (Meanwhile, you can get a OSX version on request, use the contact form or mail me!)
=> Connect => Import patterns => select your .CXM file.
Alternatively, you can also fill the memory with some random patterns (“battery out” trick) by holding RND+CLEAR while turning on the x0x.
If you have any questions, join us on #x0xb0x (freenode) at IRC (we have cookies!), send me a mail, check the forums or re-read the manual ;)
Your x0xlarge can be updated using plain midi! No more hassle with USB serial drivers, and a nice progress indication on the leds.
Alternatively you can update using avrdude & usb. Refer to the manual.
Updating using c0nb0x is coming soon in 1.02.
We are more than happy to receive any and all comments, suggestions, bug reports and requests regarding the firmware!
All hail Anton Savov (antto)!
n0nx0x2 would never exist if it weren’t for the 1000s of hours antto has spent researching the TB303. He really succeeded in making the first true 303 sequencer clone, without the annoying qualities of the original. Funny fact is, he had never owned, touched or seen a real 303 in his life. You cannot imagine how many hours, days, weeks, months, even years (I think we first started with all this about 5 years ago) we spent together on IRC getting the tiniest details right, from button mapping to led blinking algorithms and exotic 303 features most people don't even use or know to exist.
If you like n0nx0x2 (I'm sure you will ;) ) and want to motivate antto and support n0nx0x2 development and webhosting costs, you can find a donate button on the frontpage of his website: http://antonsavov.net.