old trusty DVM just died. Recommendations for a replacement?

I use Fluke meters in the field because they're pretty "bullet-proof" re. their cases. Bit when I wanted something with more functions for the bench, I didn't need something quite so stout.

I bought an Extech EX330:

It's got capacitance and frequency measurement as well as temperature measurement. (Mine came with a bead-type probe but I see some EX330 meters that are not bundled with a probe. Look closely.) I think I paid about $50.

Jameco has a good selection:

I still think there's nothing like a Fluke but the competition is closing in on them very quickly.

(I cross-posted to the s.e.repair group. I think these guys n' gals would be able to give some good experiences re. meters.)

Good luck,

The biggest drawback I've found to the Extech meters is that they are very slow to auto range (in every mode) compared to a Fluke. Also, while hunting for the right range they display bogus values in the other ranges. My Fluke 10 takes about 0.5s to go from Megaohms down to ohms and displays dashes while it's doing that. My EX470 takes 4+ seconds and displays some intermediate values. After it reaches ohms it takes another second or so to settle.

Not just the cases. My 77 got hit years ago when I got the test lead a little too close to a flyback transformer. The size of the arc suggested that I exceeded the maximum allowable voltage by one or two orders of magnitude. The meter was unfazed, no change in calibration or looks.

I agree on Fluke robustness. Pretty much the same story with my 8520A bench meter.

I wanted to make my own high voltage probe. At a flea market I had aquired some glass encapsulated resistors that were multi-megohm. I thought they would be perfect for my probe divider, so I built one in a plastic tube. Tried it at some hundreds of volts and it seemed to be working as expected. I applied it to something like 1700 V. The tube was clear plastic, and to my horror the resistor lit up with plasma and ugly clicking noises came out of the meter. Looking at the meter, the fluke display had switched to Klingon or something. Expecting disaster, I power cycled the Fluke. It came back to life and was fine.

That resistor still baffles me. As I said it was in a glass tube and was at least an inch long. It looked perfect for HV. My guess is that it was filled with some gas to deliberatly short itself at some voltage in the low KV range.

Did you clean all body oil and other contamanints from the resistor before you used it? A single fingerprint on a one inch glass HV resistor could cause arc over, and for it to self destruct.

It clearly arced inside. It looked like a neon tube not a simple arc-over. The voltage I was measuring should not have come anywhere close to arcing across that length. That's why I'm thinking it was designed to do that. I looked for the resistors yesterday to see if I could find markings, but I can't find where I stashed them now.

Damn... the TerrellTard got one right.

Fact is, mere "coffee breath" can cause them to fail.

A bath in hot IPA (microwave a cup full to boil point), and a new flux brush will do a VERY good job.

If it is a single arc event, it won't always cause it to fail completely. The arc has to sustain long enough to form carbon arc trails.

Try a Simpson 360.

Is that some kinf of BIZARRE joke ?

Bwahahahahahaha !

Graham

Always loved 'em. A friend has one. I finally persuaded him to keep it in the house and buy a cheapo DVM for garage use. It's not that the 360 couldn't take it, but he's already run it over with a car once and scratched the case.

I recommend one of these:

Dave.

It may have been a precision high impedance feedback resistor for the type of instrumentation amplifiers used on Faraday collectors and other scientific instruments to measure minute currents. They are normally only ever used at very modest voltages and are optimised for lowest possible noise in that application.

Typically they are in the 10^7 to 10^9 range - their manufacture was (is?) a black art.

Regards, Martin Brown