I bought 2 Fluke 45 for $60 and soon after sold one for $50. The remaining one is a bit sick: resistance measurement isn’t quite right. Let’s look into that.

But first I wanted to verify voltage measurement. Here’s the result with 2 other totally uncalibrated benchtops.

The good: they all 3 measure the same value.
The bad: I’m using a voltage reference that’s supposed to output 5.0000082V.

The measured value goes up and down quite a bit too, and that’s 1 hour after switching it on.

For the resistance test, I used a bunch of through-hole resistors from my stash, a set of Probemaster probes, 2 wire measurement (the 45 doesn't support 4 wire), and simply compared the 34401A result against the Fluke 45.
When I tested it with the potential buyer, a short measured as 2 Ohms and 150 Ohms measured 180 Ohm.
I'm seeing similar discrepancies here *initially* but they quickly disappeared!
Does this unit just need a bit of time to wake up?

Yup! Powered it off and let it rest for 10 minutes and we’re back at 2 Ohms for a continuity test.

So I wasn’t hallucinating when I tested it 2 weeks ago. The unit that I sold had a yellowed plastic case and the VFD had faded a lot. If it only test 10 minutes of warming for the measurements to be correct, I can totally live with keeping this one.

Let’s see how long it takes to settle…

25 minutes later…

And now that I think about it: when I started testing and the result was off by 20%, the unit had already been on for at least an hour. Somehow, it suddenly flipped into measuring resistance correctly.

Some kind of modal behavior?