I've had a lot of trouble with the load n lock system in my F512. The first one got fried when a friend plugged it into a preamp with phantom power turned on. When Dave Gonzales asked me about my guitar at LMG 2 or 3, he said he'd send one that was in the office in Arizona, it was dead on arrival. Bought one, probably from Reverb or eBay, and it worked. Then a year or so back, the batteries were slightly corroded, but after cleaning with vinegar and Deoxit, it worked okay. Then, last week when I was checking it in prep for an open mic, I put in new batteries (I had taken them out after my last use about a year ago to avoid another attack of corrosion), and it doesn't work. So, third strike, it's out. Since it's pretty hard to find a replacement, I'll probably take it to my luthier and have him plug the oversize hole and fit a new pickup of some sort, maybe the D-Tar Multi Source system. Open to suggestions, I don't mind spending serious money, after all, I DID get an unbeatable deal on the guitar at LMG 1!