EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: bug13 on August 29, 2013, 05:44:50 am
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Hi guys
I got a UT61E from UNI-T, say I got a 6V source, when I first turn on the meter, say it read about 6.500V, and reading will run down slowly from 6.500V to about 6.180V, in about 1-2mV step. |O
What's the problem and how can I fix it?
thanks guys
PS1: My voltage source is from a power supply, not a battery
PS2: My other cheap meter get about 6.00V or there about, and stay there.
PS3: I can fix it with messing around the trim pot likehttp://gushh.net/blog/ut61e-calibration/] [url]http://gushh.net/blog/ut61e-calibration/ (http://[url) [/url], but the same problem happen after a day or two. :palm:
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Are you hooking up the meter to the unloaded supply? Then the high impedance of the input jacks may not let the power supply bring its voltage down quick enough. Try putting a load between the two pins on the supply then measuring. See if that doesn't fix it.
Cheaper meters often have much lower impedance which might be low enough to allow the power supply to function (with the meter serving as a load |O)
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Are you hooking up the meter to the unloaded supply? Then the high impedance of the input jacks may not let the power supply bring its voltage down quick enough. Try putting a load between the two pins on the supply then measuring. See if that doesn't fix it.
I put a 100ohm resistor across a 3V source, same thing still happen, it reads 3.2xxV and slowly run down toward 3V
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Something's wrong with your meter.
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Something's wrong with your meter.
Any idea on how can I fix it?
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None whatsoever.
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I hope this is single isolated incident, typical chinese manufacturer have ridiculous warranty, compared to normal western companies.
Usually sellers wash their hands unless it is dead on arrival.
Where I live, even if product has its warranty expired, then one can still claim it to be fixed/replaced by manufacturer/importer because every product has its reasonable expected life cycle. When a washing machine (for example) has 1-3 years warranty, people still expect it to last for at least 5 years or more, when their old good quality washing machine with all electromechanical (not much if any electronics) lasted for a good 10-20 years.
PS3: I can fix it with messing around the trim pot like http://gushh.net/blog/ut61e-calibration (http://gushh.net/blog/ut61e-calibration), but the same problem happen after a day or two. :palm:
Does your multimeter get banged around a lot? From what I have read, the pot is really sensitive when adjusted. I think some people have replaced their cheap chinese copy trimmers with genuine good quality ones, have you considered that? Do you see anything wrong with the multimeter pcb? Does it have flux residue or something on it?
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Something's wrong with your meter.
Any idea on how can I fix it?
You could try to replace a new capacitor nearby pin37-38 of ES51922 (main chip of UT61e).
Maybe you could remove the capacitor and check the result first.
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I have tried both methods, no good |O, I think I have to buy another one, a proper one