uni-t ut61e voltage problem - Page 1
Forum section: electronics / testgear

author: bug13
author_rank: Regular Contributor
timestamp: August 29, 2013, 05:44:50 am
content: Hi guysI 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.What's the problem and how can I fix it?thanks guysPS1: My voltage source is from a power supply, not a batteryPS2: 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/] http://gushh.net/blog/ut61e-calibration/, but the same problem happen after a day or two.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: August 29, 2013, 05:57:49 am
content: 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)

author: bug13
author_rank: Regular Contributor
timestamp: August 29, 2013, 08:38:06 am
content: Quote from: PedroDaGr8 on August 29, 2013, 05:57:49 amI put a 100ohm resistor across a 3V source, same thing still happen, it reads 3.2xxV and slowly run down toward 3V

author: Monkeh
author_rank: Super Contributor
timestamp: August 29, 2013, 12:35:50 pm
content: Something's wrong with your meter.

author: bug13
author_rank: Regular Contributor
timestamp: August 29, 2013, 09:46:19 pm
content: Quote from: Monkeh on August 29, 2013, 12:35:50 pmAny idea on how can I fix it?

author: Monkeh
author_rank: Super Contributor
timestamp: August 30, 2013, 04:51:51 am
content: None whatsoever.

author: Legit-Design
author_rank: Frequent Contributor
timestamp: August 30, 2013, 05:03:27 am
content: 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 itsreasonable 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.Quote from: bug13 on August 29, 2013, 05:44:50 amDoes 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?

author: jarvis
author_rank: Contributor
timestamp: August 30, 2013, 05:20:08 am
content: Quote from: bug13 on August 29, 2013, 09:46:19 pmYou 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.

author: bug13
author_rank: Regular Contributor
timestamp: September 01, 2013, 05:07:58 am
content: I have tried both methods, no good, I think I have to buy another one, a proper one