Hi John, As far as batteries are concerned you have several options. 1. The simplest fix is to use two silver oxide batteries. These have an output of 1.5 volts rather than the 1.35 volts for the mercury battery. The silver oxide batteries are usually smaller and would require the use of an O-ring or something similar to make make them fit. You would then compensate for the voltage discrepancy by using a different ISO speed setting on the camera. 2. If the camera has an adjustment for the light meter you could recalibrate it for silver oxide batteries. This is usually a variable resistor in the camera body. 3. A Schottky diode 1N6263 or similar could be added to the meter circuit to compensate for the use of silver oxide batteries. There are many articles on the net about doing this with older cameras. 4. Another simple fix is to use zinc-air hearing aid batteries which have the same voltage as mercury batteries. Disadvantage is that they discharge even when the camera is not in use. However, removing the batteries and placing a bit of tape over the air holes will stop this. There is a zinc-air battery as large as the PX625 mercury battery. In any case they are cheap. You will have to drill a small hole in the cameras battery cover to allow air to pass through. Hope this helps. Jerry -----Original Message----- From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of John Black Sent: Monday, July 18, 2005 12:36 PM To: pure-silver@xxxxxxxxxxxxx; MUGers@xxxxxxxxxxxxxxx Subject: [pure-silver] Thanks Thanks for the info on my flea market find. I'm of an age where Googling it slips my mind as a first option but I did that and found a wealth of info. Seem like the inscription on the bottom plate really was the shutter. Now I need to find a modern equivalent to the RM640, A640 or HM-N battery which was mercury. Thanks again. JB ======================================================================== ===================================== To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there. ============================================================================================================To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.