Fluke 189 fails capacitance auto range, other - Page 1
Forum section: electronics / testgear

author: Finderbinder
author_rank: Regular Contributor
timestamp: March 18, 2023, 09:12:56 pm
content: Actually here are few problems.1. When I turn wheel to capacity, it shows 66pF (without leads). It is offset, but stable. Is it possible to correct offset?2. When I measure say 470uF (on auto range), it shows ok. Then I disconnect this cap and... device starts to jump in different ranges, shows different values, include negative; and this may last infinitely or sometimes it returns to 66pF. If I connect say 40nF while it is jumping it shows 40nF correctly and upon disconnecting it returns to 66pF (always). Or I can turn wheel forth and back to capacity to return it to 66pF.3. DC mV sometimes shows tens of uV with probes shorted, sometimes few uV, and sometimes 0 or negative values (unstable).4. AC mV shows ~150 uV with probes shorted (stable?). Reduces few times if I keep my hand nearby multimeter (even not touching it).5. AC V shows ~3mV with probes shorted (stable?).Device is very clean inside, also outside.Any suggestions?

author: Fgrir
author_rank: Regular Contributor
timestamp: March 20, 2023, 05:13:04 pm
content: Sounds to me like everything you describe is normal.1) I see 64pf without leads on my 189, Fluke specs 2% + 5pF accuracy in the lowest cap range, but with the following note:Quote2) I see similar behavior from cap autoranging on mine, seems to be noise pickup preventing it from ranging down.3) Specified accuracy in the lowest mV ranges is 20uV, so might not be out of spec. Are you sure your shorting connection is stable?4) and 5) All AC ranges have the following note:Quote

author: mwb1100
author_rank: Frequent Contributor
timestamp: March 20, 2023, 06:27:10 pm
content: And just to help confirm what @Fgrir said, my 189 behaves pretty much the same except:- for #2 when I have leads in the meter it settles to about 87nF instead of 66nF- for #4 my 189 shows about 70uV

author: bdunham7
author_rank: Super Contributor
timestamp: March 20, 2023, 06:33:29 pm
content: Quote from: Finderbinder on March 18, 2023, 09:12:56 pmRead the specifications section of the manual?Just now I pulled my 189 off the shelf, turned it on to capacitance and it read "0.066 nF".

author: coromonadalix
author_rank: Super Contributor
timestamp: March 20, 2023, 10:44:05 pm
content: same for capacitor 0.065 nF push REL all goes to zero0.0028 V ac shorted probes0.050 mV ac shorted probes

author: Finderbinder
author_rank: Regular Contributor
timestamp: March 21, 2023, 10:12:03 am
content: Well... Uni-T UT71E shows 0 in all tests above. That is why I suspected my "new" 189 to be defectiveSo my UT71E is highly superior to 189? I expected not worse behavior from 189 at least. But I got only super fast continuity advantage so far as I can tellbtw if all 189 shows ~66pF with leads off, this means systematic error which should be (able) eliminated automatically....and yes, I repeated tests multiple times with different leads.

author: Swainster
author_rank: Frequent Contributor
timestamp: March 21, 2023, 10:40:24 am
content: Haha, here is a thread complaining about almost the exact opposite - i.e. that the UT71E is reading zero when another (as it happens another Fluke) is correctly reading non-zero:https://www.eevblog.com/forum/testgear/ut71e-current-measurement-errorThe reason is that in certain ranges (commonly AC ranges), some multimeters' software just reports zero instead of a potentially inaccurate low value. Typically this threshold is 5 to 10% of the full scale reading. Other multimeter manufacturers don't bother with this 'feature' - maybe because they know that they are going to get complaints either way they handle it.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 21, 2023, 10:40:36 am
content: i would say differently, some meter(s) have an auto zeroing, its a way to force an zerosome members like the fact that we see really whats happening instead of using some trickery ..that was debated here on some threaduni-t meter doesn't impress me loll until you have their high end models

author: bdunham7
author_rank: Super Contributor
timestamp: March 21, 2023, 01:29:38 pm
content: Quote from: Finderbinder on March 21, 2023, 10:12:03 amPerhaps! Find a 20-50pF capacitor and measure it with both instruments and see how they do.

author: Finderbinder
author_rank: Regular Contributor
timestamp: March 21, 2023, 04:42:22 pm
content: Quote from: bdunham7 on March 21, 2023, 01:29:38 pmYou are right, at that range UT71E is near uselesswhile 189 counts almost each one pF.

author: BeBuLamar
author_rank: Super Contributor
timestamp: March 21, 2023, 11:27:51 pm
content: My Fluke 189In capacitance probe not connected it shows 0.070 nF.With probe shorted it shows0.001 mV DC0.030 mV AC0.0035 V AC.So it's about the same as your meter.

author: Fungus
author_rank: Super Contributor
timestamp: March 22, 2023, 12:40:12 am
content: Quote from: BeBuLamar on March 21, 2023, 11:27:51 pmWith my 187 I get:Capacitance mode, no probe: 0.068nF0.001 mV DC (ie. 1 count)0.015 mV AC ...but if I wave my hand near the meter it jumps up into the hundreds of mV.0.0029 V AC.So about the same as yours.The plural of anecdote is "data", right?

author: Topdedcenter
author_rank: Newbie
timestamp: August 20, 2023, 09:59:05 pm
content: Came here looking for answers regarding my FLUKE 189 that does the same thing in capacitance mode. I actually opened up my meter first, found the leaking supercap, then started browsing around the forums and found that it can simply be removed since replacements are near impossible to find at this point. But the cap has been removed and the meter still turns on and measures the same standing capacitance with/without leads attached. Thanks for all the info.Btw, i found this meter at a yard sell for like $30 from a dude who appears to have purchased a government bid wholesale shipment. There were a couple more at the time, and i regret not grabbing them, oh well. It's a solid meter and has a much faster reading response time than the basic flukes used at work.