[aoeu]

It's a late Spottie sn 2999284 and when I bought it the mirror was locked up. I took the film out and removed the base. Now the mirror works just fine even though I didn't actually do anything. There is another issue, however. The battery cap is solidly stuck. I've read some threads discussing heat, cold, petroleum solvents and acetic acid in varying concentrations. Before I do that I would like to ask this question: Without any battery power is the needle normally about halfway between the middle and the bottom of the scale?

[TomB_tx]

Yes - they used a balanced circuit that moved the needle in both directions, so it's rest position is near the mid point.

The stock battery cover actually has two small holes drilled in the slot as vents, although the corrosion often plugs them so you can't see them. You can fit a needle-point spanner into these holes to get better leverage.