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Is the battery packaged inside the RAM chip, or located inside teh scope on a circuit board? If it's by itself on a circuit board, you might be able to maintain the voltage on the RAM chip with an external bench power supply (wire leads soldered temporarily running to a bench supply set to the correct voltage, with some series resistance added) before removing the old battery and after you install the new battery then disconnect the bench supply. Thus this should... keep the data in the RAM chip alive. I haven't tried this, so YMMV.

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