Fluke 187 - strange problem with resistance measurement - Page 1
Forum section: electronics / projects

author: misisoso
author_rank: Contributor
timestamp: January 08, 2013, 06:28:36 am
content: Hello!I bought yesterday used Fluke 187 meter and everything worked perfectly before I changed frequency settings from 60 Hz to 50 Hz. Then, ohm measurement was still showing value appx. : 152,52 ohms, or such... when I shorted the probes, it went to zero... but after unshorting probes, it went back to 152,52 ohms. The problem is fixed by selecting the 60 Hz again... Any ideas guys?Michal

author: Unknown
author_rank: Unknown
timestamp: January 08, 2013, 09:28:17 pm
content: Changing the line frequency will change the integration time of the ADC. I guess it switches a cap or resistor, which may be faulty. Is this just resistance or does it also affect other functions?I think Dave posses a partial schematic of this DMM, not sure if he posted it somewhere public, otherwise you might try pinging him.

author: retiredcaps
author_rank: Super Contributor
timestamp: January 08, 2013, 10:29:30 pm
content: I just tried the same thing on mine and I can't reproduce the problem.

author: misisoso
author_rank: Contributor
timestamp: January 09, 2013, 06:11:06 am
content: Hello. Thank you for answer. It is a lot difference, if I measure at 60Hz, whereas we have 50Hz ? I use it for electronic purpose. It would matter only if that settings was used for some filtering I think.

author: misisoso
author_rank: Contributor
timestamp: January 09, 2013, 06:14:48 am
content: Alm, thanks for reply. I will try other measurements, I have not tried so far. I hope it is only the cap or resistor you mentioned. I thought that it would be something like that, but I cannot find any schematic, Fluke company did not reply and I contacted Dave and he did not know about the problem. But I think I saw one video about the same problem, but I did not pay much attention to it, because at that time I have not really thought about buying Fluke meter.

author: misisoso
author_rank: Contributor
timestamp: January 09, 2013, 01:22:29 pm
content: Hello. I tried other features as well, and they also does not work, when the meter is switched to 50Hz... Is it the capacitor or resistor?

author: retiredcaps
author_rank: Super Contributor
timestamp: January 09, 2013, 09:59:40 pm
content: This may not be related to your problem, but I thought I would mention it anyways.I have only worked with a 87IV and 187 (both the same) and both had battery leakage.Since yours is used, do you have any battery leakage?Can you also post some photos of your pcb (both sides)?

author: misisoso
author_rank: Contributor
timestamp: January 09, 2013, 10:14:04 pm
content: Hello. Thank you for reply. No, there are no signs of battery leakage on battery cover, bottom cover, terminals, or PCB... PCB from behinds looks like it never saw light before... no physical damage of any kind... and I have not checked the front side yet.... but I will... If only I had schematic, I would be able to locate the problem with higher probabilty.

author: misisoso
author_rank: Contributor
timestamp: January 11, 2013, 08:03:24 pm
content: Part 1 photos of my Fluke 187

author: misisoso
author_rank: Contributor
timestamp: January 11, 2013, 08:03:59 pm
content: Part 2 photos of my Fluke 187

author: misisoso
author_rank: Contributor
timestamp: January 11, 2013, 08:04:35 pm
content: Part 3 photos of my Fluke 187

author: misisoso
author_rank: Contributor
timestamp: January 11, 2013, 08:05:10 pm
content: Part 4 photos of my Fluke 187

author: misisoso
author_rank: Contributor
timestamp: January 11, 2013, 08:05:56 pm
content: Part 5 photos of my Fluke 187

author: misisoso
author_rank: Contributor
timestamp: January 11, 2013, 08:06:27 pm
content: Part 6 photos of my Fluke 187