Yes; Mike is right - it's time for a new one.

The Fluke 180 was (is) just a Bio-Tek 180 ... and I'm pretty sure I can recall using that one back in 1987 (OK, it may have been a 170).

This link may help to guide you.

And this one is good for reference purposes.

But "fluctuating voltages"? Have you taken a look inside? Have you got a decent earth?


If you don't inspect ... don't expect.