[The Philpott]

To clarify, the 1.5v cell in the meter (which these days has to be converted to a D cell as the old cell is obsolete) will make the LOW and MEDIUM resistance range on the meter work. (which gives you 50 or 500 ohms at centre scale)

To get the HIGH resistance range working (5,000 ohms centre scale) you need 9 volts (hence the pair of 4.5v batteries which are wired in series.)

With a combination of help from here and looking at tutorials i would say this is something you are highly likely to be able to pick up.

I agree with what people have said about your AVO. It is well worth dusting off and using. If i was nearer i would put it thro' it's paces for you. Certain elements of an old AVO are not dissimilar to the workings of a clock or old telephone exchange- a fusion of electrical and mechanical functions and principles.

I should say it is comparatively easy to kill an avometer if you are new to electrical testing and analogue meters- best you have the booklet that goes with it (should be a scan easily available)

Dave