Products > Test Equipment
FLUKE 189 DC reading problem [with video]
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kamcm:

--- Quote from: coromonadalix on July 15, 2019, 01:16:50 am ---I dont want to drag your post, but if you dont need time related logs   gently remove it to be sure,  when this puppy goes bad,  you may have excessive battery current draw or an leakage on the pcb,  removed mine on my 3 fluke 189 until i bought an substitute.

They are known to cause some problems  in the fluke 89IV - 189 and 287 or 289

--- End quote ---

I just de-solder the battery off the board and clean the spot under the battery.
But still having the same problem.  :-//
coromonadalix:
Has windsmurf wrote : do you have any contaminants on the board ??   Any solder residues ??   under the rotary knob functions, is there any grease / too much grease ?

Or Maybe your meter need some calibration ??



I have my oldest fluke 189 showing a strange behaviour only in ohms measurement under 10k ohms, the ohms ranges seems to works fine, but this one in a 27mhz rf section doesn't show the same values as my other 189 ??,  tested all ranges with references resistors, all is ok,  all input impedances are fine, but in my rf circuit i have a strange error ??  Maybe its the Fluke asic ic who as a problem ??

CDaniel:
Should be tested on all functions , maybe if we know what is working right and what is not will figure out the cause .
kamcm:
Here is the test on every functions.  Any help would be really appreciated :)

=====================
AC

ACV
Actual 5V
Measure 4.72V

Actual 0.3V
Measure 0.0111V

AC HZ
Actual 50.00Hz
49.96HZ to 50.02 HZ, keep jumping

-------------------------------
AC mV

Actual 300mV
Measure 283.94mV

AC (mV) HZ
Actual 50.00Hz
49.96HZ to 50.02 HZ, keep jumping


======================

DC

Actual: 10V
Measure: 8.888V

===============
DC mV

Actual: 500mV
Measure: 470.72mV


=================
ohm

actual: 1ohm
measure: 0.06ohm

actual: 5ohm
measure: 0.19ohm


actual: 10ohm
measure: 0.38ohm

actual :20ohm
measure: 0.79ohm

actual: 50ohm
measure: 37.66 ohm

actual : 100ohm
measure: 88.93ohm

actual : 1k ohm
measure: 0.8893 kohm

actual: 5k ohm
measure: 4.6855 kohm


=================

mA

Actual : 20mA
Measure: 19.856mA

Actual: 10mA
Measure: 10.072mA

Actual: 5mA
Measure: 5.214mA

Actual: 4mA
Measure: 4.062mA

Actual 3mA
Measure: 2.763mA

Actual 2mA
Measure: 0.076mA

Actual 1mA
Measure: 0.038mA


===================

Actual : 100uA
Measure: 101.31uA

====================





CDaniel:
So pretty much everything is bad and in the low side ... the schematic for this meters I don't think it's available but you should try to find and measure the precision voltage reference and power supplies for the analog part ,  before condemning the ASIC chip itself ...
The input protection can't explain the current measurement being off ...
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