Wierd household voltages...it's baaaack!

Put a 60 watt bulb in parallel with the volt meter when you make the measurements, then report the results.

If I understand this, you read 75 volts n-g when the light switch is not conducting, and 0 v when it is.

best shot from afar - (unless you are near hi-power lines or a radio/cell/tv tower) 1) think ground (in fixture) to neutral as a current path rather than neutral to ground as the path 2) Also think all wires TO the hot side of the switch having 120 v before the switch is thrown, and all wires AFTER the lamp as sitting at neutral/ground when the switch (which connects the lamp to neutral) is thrown. Note that the wires/parts between the lamp and the switch neutral screw are the only ones that change potential when the switch is thrown

My guess is the problem is a pinched/damaged wire in/after the fixture (or less likely a corroded/contaminated switch), e.g., a wire after the lamp going to the switch has crushed insulation resting on the fixture/a wire. You're reading the voltage due to leakage thru the insulation -- and your reading is 75 volts rather than 120 volts because the meter itself is part of a high resistance circuit with the insulation/corrosion/contamination - (As a wild guess, I would suspect that you would get a reading closer to 120 volts if you used a higher impedance meter)

When the switch is on, the "good" path to neutral is made, the wires from the lamp to the switch neutral connector drop to neutral potential, and then the wires after the lamp no longer have the 120 volts from which you get your

I would look for a nicked, cracked, or pinched wire in the fixture/box that is touching the fixture itself - a wire or part between the lamp and the switch

- and just because, I would change the switch - often times, just moving the wires off the fixture removes the voltage.

And also check the fixture ground connection physically with the breaker off

--- there are other tricks for other conditions if this does not work - so keep us posted

There are people in the world that wire the fixture hot and switch the neutral. Some times called a California 3 way. at least it is around here. Start a mapping project and I am sure once you get beyond the frustrating part you will find some silly mistake in the wiring or something loose.

Best of luck, been there

Thanks for all the input...I won't be able to check it out until we get back from the beach at the end of the month. But I'll definitely try the suggestions posted. BTW...the guy who lived there used $30K to remodel this house...I think he could have used a chimp (no offense to you chimps) and done it for $3K judging by the way this place had been done! :>) I'll let you know what I find...