Testing a Cartridge with a multimeter

[BinaryMike]

Even the most modern digital multimeter will output a volt or two for resistance measurment...

Not true. Modern DMMs are designed specifically to keep the maximum applied voltage in ohms mode well below the forward conduction threshold of a silicon diode, which implies an upper limit of about 0.3V to 0.4V.

 

[Heaviside]

I know this was said as a joke, but my analog meter is a VTVM -- the venerable RCA VoltOhmyst. These are precisely the types of meters that could potentially put a sizable current across the cartridge. This is the meter I learned electronics on back in the 70s. For many of us, an analogue meter = VTVM.

For other purposes, it's a great meter. Measures very small resistances that a digital meter would have a hard time with. Also has a much wider frequency response for measuring AC than most digitals. Plus, sometimes an analogue meter (with a needle) can show you things that numeric meters can't.

Just to be clear.

Yes, I meant it as a joke. I've never owned one but would love to have one. I bid on one on eBay awhile back but lost it. It was an unbuilt Heathkit, and they always go for big bucks.

Thanks for the clarification.

Dan

 

[Doug G.]

Unbuilt Heathkits. Sadly, relatively rare nowadays.

I built a few and loved it.

We used to "pronounce" VTVM at work years ago as if it were a word. No vowels, LOL.

We had some VoltOhmysts, Heathkits, and some expensive Ballantines. They were used to calibrate the 8-Track (both stereo and quad) test equipment among other things. The dB scales really came in handy.

Also, what Mike said.

Doug

 

[Sir Bakerman]

This was extremely helpful.

 

[BinaryMike]

I can show you my Fluke 77 puting out 2v. in ohms mode.

Okay, then I'll eat my words. Chomp. Chomp. This is a definite possibility in DMMs with a separate diode test function. I suspect the designers found it difficult to optimize the resistance measurement function when the test voltage was constrained well below the forward conduction threshold of a silicon junction. Still, I would want to always have an ohmmeter on hand that doesn't forward bias Si junctions, for checking resistances in-circuit in SS gear. Does Fluke offer you any guidance on that issue?