The real problem with the meters is the battery damage.? Go partway through the calibration procedure (just very rough), and see if the processor will store the cal constants.? If so, you're lucky.? I have one or two that do not store the cal constants and are of little current use.? All that I have are battery damaged.? The cal procedure adjusts (IIRC) the readings down, as the meter is designed to read high without calibration.?
The high voltage needed for the AC calibration is the one real problem in calibration.? Tek recommends the 5200 series calibrator with the AC amplifier needed to get to the high voltage.? I haven't solved that problem yet, but haven't needed it since none of mine are yet working.??
Thanks Eric ¨C yep when I got it, there was battery gom all over that part of the board. I got it up and running, but this meter, as you may know, doesn¡¯t just come up and work when the cal coefficients have been lost. It¡¯s way off, so a calibration is a must. I¡¯ll keep my eyes open for one of those Flukes.
Dan
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Be on the lookout for a fluke 5200A and if possible the 5205 amplifier. These are currently my best AC standards in the lab. Also there is known issues on the DM5010 (battery damage on the processor board) just mentioning this if this has not be checked and corrected in this unit.
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The High AC volts on the dial a frequency is some of the hard part of doing meters. I have run in to meters that need 2 or 3 different voltage and frequency combinations to get an alignment done.
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Eric/Zen
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I have a DM5010 that I would love to calibrate. The difficult items in the cal procedure are 190V and 700V at 200Hz.
I have tried to string some standard 70V line audio transformers together and use an audio power amp, but it doesn¡¯t seem to like that load and it disconnects. Haven¡¯t tried anything else yet.
I have other good meters to use as my ¡°standard¡± so I am thinking I don¡¯t need a sophisticated calibrator. Not trying to get NBS traceability here, just a working meter.
I don¡¯t even really need this meter¡ just want to complete the repair! I really should just try to sell it as-is maybe.
Thanks
Dan
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I have lots of equipment to do what I would call hobby level (non-NIST) equipment calibration. Perhaps quite a few of us can say the same but I think the one area of weakness for most of us is a variable frequency, variable AC voltage source.? I have, for example, a bunch of Fluke bench multimeters I thought I would test/calibrate last year. Everything was easy till I hit the AC cal sections. An AC calibrator would be very useful to me as I have a lot of meters, many have high frequency ranges up to or beyond 1Mhz, that call for different frequencies and a wide range of voltages.
What I would expect would be a low distortion sinewave with calibrated voltages from millivolts to over 300V. Frequency might range from perhaps 10hz to 1Mhz. Not necessarily continuous frequency but a range of frequencies required by most test equipment for calibration. It would be convenient to have output voltages that were calibrated/selectable for RMS, average, peak and peak to peak to align with calibration procedures across a large variety of test equipment. This would just be selections to vary the sinewave amplitude and perhaps a peak selector. Ideally it would have a low source impedance such that on at least some ranges you could have a calibrated AC current source.?
I can think of several designs that would provide the functionality but really need to think this through and limit the features to a more targeted amount. I have done some preliminary investigations to determine what ranges and frequencies I need for most of my HP, Fluke, Heath, Instek, Simpson, and other brand multimeters.
I think this would solve a big hole in hobbyist metrology. DC voltage, DC current and resistance are pretty easy to setup on the average workbench and get pretty accurate results. Frequency is pretty easy as well with GPS disciplined oscillators. AC is harder to deal with. While equipment exists to purchase/repair, it is generally pretty expensive and may have a limited range of voltage or frequency, unless it is really expensive.? I suspect most of us end up kludging up a test setup to at least get some of the required voltages and frequencies, unfortunately skipping many combinations.
I would like to get some thoughts from others about how they do AC calibration outside of a rheostat/isolation transformer on a 50/60Hz power line, or a sinewave generator for low voltages.
