Quick cleanup of the AVO and looked in the battery compartment. the 15v battery ( eveready) is not leaking, but did not check the actual voltage, will save it for later when checking the meter a little better, but it probably is reasonable on most ranges in any case, or about as good as most analogue meters of it's vintage. Case cleaned up nicely with some application of Teak oil, but I will need to restitch a corner a bit, and missing the carry strap. Low resistance ranges are done by the big D cell battery, and the one in there is a Duracell unit, made in USA Bethel CT, that had an expiry date of March 2004. Just started leaking a bit, the negative terminal is discoloured, and the battery contacts have a slight green blue film to be cleaned off them. Battery still works, 1.526V open circuit, and still capable of delivering over 4A into a test load. Going to it's new home now, and after it has been filed in the round file it will relocate to a nice final resting place.