Hello everyone,
I am a long time lurker who finally mustered the courage to post a question.
I have recently acquired a second-hand 189 multimeter. All functions work fine, relatively clean to begin with and cleaned up easy. By the appearance nobody has been inside (except me) and minimal wear on the selector tracks. Supercap very crusty, but PCB and other components around don't have any signs of corrosion. I replaced the supercap.
Main issue with the meter is that it reads lower than any of my other meters. I do not have calibration setup or calibrated sources, but I have setup measurement of 189 compared to 289, 87V, 117 and 101. 289 is less than 2 years old, bought new; 87V second hand unknown vintage; 117 brand new and 101 bought less than a year ago.
For practical mesurements (where probe setup does not affect much) I see less than 0.2% discrepancy between 289-87V-117-101, in many cases less than 0.1%. But the 189 is consistently 1%-1.5% lower than the rest. I have checked V DC, mV DC, Ohm, mA DC and mV AC and all behave very similarly. Data table below. For current all meters connected in series with process calibrator and 24V supply. For Ohms measured decade box with each (yeah, low ohms affected by probe resistance, I did not do rel). For V abnd mV measured with each meter one-by-one. Not the most exact setup, but that is how I would be using the meter, so that is what matters to me. To be clear, I would be happy with the same level of error that I see between 289-87V-117-101.
I checked the input protection on components and visually inspected everything on the board. Cleaned the plugs. New batteries. Yet nothing changes. At this point I am starting to think that calibration is what is needed. Does this sound like there is some other defect I should be chasing before resorting to calibration?
Best regards,
rC
V DC
189 | 289 | 87V | 117 | 101 |
0.1091 | 0.1120 | 0.1121 | 0.113 | 0.113 |
0.0560 | 0.5139 | 0.5138 | 0.513 | 0.512 |
0.9978 | 1.0136 | 1.0138 | 1.015 | 1.012 |
4.9577 | 5.0153 | 5.015 | 5.015 | 5.012 |
9.893 | 10.015 | 10.012 | 10.01 | 10.00 |
19.782 | 20.010 | 20.00 | 20.00 | 19.99 |
mV DC
189 | 289 | 87V | 117 |
114.60 | 115.54 | 115.5 | 116.5 |
213.35 | 216.36 | 216.6 | 215.2 |
313.50 | 316.20 | 315.8 | 316.6 |
510.60 | 514.60 | 515.6 | 515.8 |
Ohm
189 | 289 | 87V | 117 | 101 |
5.76 | 5.61 | 5.9 | 5.5 | 6.2 |
49.76 | 50.41 | 50.4 | 50.7 | 51.0 |
495.4 | 508.0 | 500.7 | 501.5 | 503 |
4943 | 5009 | 5000 | 5001 | 5000 |
49430 | 50120 | 50100 | 50090 | 50100 |
493100 | 500000 | 500100 | 499800 | 500000 |
4941000 | 5006000 | 5004000 | 5000000 | 5000000 |
mA DC
189 | 289 | 87V |
3.880 | 3.999 | 4.01 |
7.849 | 7.996 | 8.01 |
11.814 | 11.994 | 12.01 |
15.775 | 15.992 | 16.01 |
19.737 | 19.991 | 20.00 |
23.697 | 23.989 | 24.00 |
mV AC
189 | 289 | 87V | 117 | 101 |
3.691 | 3.651 | 3.92 | 3.8 | 7.6 |
17.72 | 17.844 | 17.94 | 17.9 | 18.8 |
34.879 | 35.165 | 35.28 | 35.2 | 35.3 |
171.72 | 173.03 | 173.12 | 172.9 | 172.3 |
355.81 | 358.82 | 359.5 | 359.1 | 358.6 |
502.8 | 505.50 | 506.3 | 505.7 | 504.6 |