I bought 25 Schottky diodes on ebay fir $6. I put one in one of my junker OM-1 bodies. It was difficult soldering to the stainless battery contact but it works great. The meter has not been calibrated and the camera has not been serviced, so who knows how in-accurate it is, but the pictures came out fine. Cost about 25 cents. Does anyone really need to build an exotic voltage regulator or a grip with AA batteries?