I recently purchased a MD-12 on ebay to pair with my Nikon FM. I just received it this afternoon and it doesn't operate. The seller was most kind and refunded me the entire purchase amount including shipping, and said that I could keep the drive and start a career in camera repair. I took the top cover off to see if there were any corroded battery contacts, but didn't go any further than that. I did not want to remove the wires that were on top of the chip board, and I didn't want to remove the chip board to go any lower to check the battery contacts. Are these things expensive to repair, and is it worth trying to save? It in great cosmetic condition. How reliable are these things today? I realize that they are older pieces of equipment, but are the ones that work still fairly trustworthy?