I changed the battery on my AN1X this weekend. Radio Shack sells the correct battery--a 3v CR2450--used for blood pressure monitors--who knew?
I hadn't used An1X Edit for over a year so it took a minute to figure out how to back up my patches.
Opening the synth is easy enough with a screw gun. The old battery pops right out. The new battery did not pop right in--it's a 64th of an inch too thick so we jury rigged it with a lot of electrical tape. Seems to work.
I got weird error messages after I powered up. You need to do a factory reset before you can load your own sounds (I did anyway). Yamaha has instructions for performing a factory reset here:
http://www.yamaha.com/yamahavgn/CDA/KnowledgeBase/KnowledgeBaseDetail.html?CNTID=11049&CTID=401120Then I used AN1X Edit to put in my custom sounds. I had a friend help me. He almost convinced me to pay him a hundred bucks so he could do the synth all up in walnut end pieces so it would look like a boutique Mini Moog. I still might one of these days.
And totally off topic, I noticed Native Instruments has a free version of Reaktor. I've downloaded it, but haven't had a chance to play wit5h it.