EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Harvs on May 17, 2013, 08:05:11 am
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I've got a 3456A that I think has a problem, trying to measure a resistance above about 100k is a hopeless exercise.
The 3 least significant digits oscillate at about 1Hz. It gets worse the higher the resistance measured, with a 10M resistor it can't hold a value within 1% It also does this to a lesser degree on the voltage ranges.
I always figured it was just something I was doing wrong. But I figure if I get a 500k 1% metal film resistor, and clamp it directly into the screw down binding posts, I should reasonably expect that I would make that measurement, or is there something stupid I'm missing here?
I remember a thread maybe a year or two back (I can't find it now) which I think Vincent was talking about some caps in them always going bad over time. So I was thinking maybe there's some power supply ripple getting through and putting things out of whack?
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Are you setting it to 100 PLC, and filter on to reduce noise in the measurement?
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Are you setting it to 100 PLC, and filter on to reduce noise in the measurement?
Yep, instability in measurement is still there.
My Escort 3146A 5 1/2 digit is solid as a rock measuring the same things, and it should be the lesser meter as I see it.
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I have 3 of these, no issues measuring ohms to any range. Have you run a self diagnostic on the 3456a?
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Yeah don't show anything on the self test.
Thanks for that vital piece of info, that yours don't do it. Leads me to a more certain conclusion that there is something a miss.
I'll crack the lid and measure some voltages.