Why do I do this to myself? Do I really need another multimeter? I’m a sucker for military and scientific gear, you know “Boatanchors”. This is a ME-297/U also known as AN/USM-223. I actually found the manual online. It looks like it takes one C cell and two AAs. Wrong. I should have known. It’s not even that old, 1974. The single battery is a BA42 or BA2042 (the cold weather version). In fact, a C cell will work here. The other batteries are BA1312, mercury cells which are 1.35V each. You need three per slot. Impossible to find, really. That’s 4.05 volts per slot. I found some interesting info on the web. Radio Shack has a battery that’s the size of a AA but is 3.6V. That’s a difference of .45V. Apparently this works. (called Radio Shack, their code is 23-037: Tadiran TL-5903 3.6V/2200mAh Lithium “AA” Battery, $16.99!!!!!!! batteriesandbutter.com has them for $7.50 and one made by Xeno, XL-060F for $3.50. I don’t know anything about this outfit). Maybe three AA cells and a voltage divider circuit, per slot, would work. Three AA cells are also .45V off, in the other direction. You could also use three FSN 6135-269-5843 button cells, but these are also 1.5V each (batterytex.com has them for $1.70 each, I’ve not ordered from them before). At first I thought that I paid too much for this thing, but Fair Radio has them for $135, a modified version that uses one C cell and six AA cells. The switch and lights were also from the same vender. This flee market wipes me out. It’s an epic adventure just getting there. Ride my bike to the ferry terminal, and take one across the bay. Then a short ride to the fair. It’s so big that even after hours of walking around, it’s almost impossible to see all the venders. I’ve only done it once.