Fluke 89 IV slow settle in 5V range - Page 1
Forum section: electronics / testgear

author: bdivi
author_rank: Regular Contributor
timestamp: December 06, 2013, 07:13:27 am
content: Hello,I have recently purchased a used Fluke 89 IV. The unit seems to be in working order and in tolerance.There is one issue however that I need help with.When measuring DC voltage the 5V range takes a couple of seconds to settle and that is very distinct compared to all other meter ranges and also compared to my Fluke 187.I assume that it is an issue with the front-end but I do not have schematics and have no idea where to start the diagnostics.I will appreciate any advice or schematics (I read the circuit should be the same for 87 IV as well as 187/189).Cheers

author: retiredcaps
author_rank: Super Contributor
timestamp: December 06, 2013, 08:38:04 am
content: Quote from: bdivi on December 06, 2013, 07:13:27 amYou probably won't find schematics for the 87IV, 89IV, 187 and 189.If you got this used and abused, you can try the following:1) wash the pcb with IPA and let it dry thoroughly.2) check the PTC - it should measure around 1.1kohm.3) check the MOVs - it should measure 0L (infinite) resistance with another multimeter.4) check the fusible resistor - it should measure around 1kohm.

author: bdivi
author_rank: Regular Contributor
timestamp: December 06, 2013, 12:48:56 pm
content: Thanks retiredcaps,I did wash the board and also visually inspected it and found no apparent issues.I will make the measurements you suggested and report back in the coming days.Cheers

author: retiredcaps
author_rank: Super Contributor
timestamp: December 06, 2013, 05:32:25 pm
content: Other suggestions.5) Clean input jacks with IPA.6) Inspect and possibly resolder/reflow solder on input jacks.

author: bdivi
author_rank: Regular Contributor
timestamp: December 09, 2013, 07:21:03 am
content: All input protection circuitry checked - unfortunately no issues found.I can measure however the same slow settle problem right at the ADC pin, which makes me believe that there is still something wrong in the path from input to ADC - clipping diodes, range dividers, filtering ...Any help is appreciated

author: retiredcaps
author_rank: Super Contributor
timestamp: December 09, 2013, 08:20:50 am
content: Long shot, but is your line frequency on the 89IV setup as the same in the 187?

author: bdivi
author_rank: Regular Contributor
timestamp: December 09, 2013, 09:11:05 am
content: yes, it is 50Hzand I also tried 60Hz - no difference

author: ModemHead
author_rank: Frequent Contributor
timestamp: December 09, 2013, 11:25:34 pm
content: When you say slow settling time, do you mean it slowly rises to the correct reading, over-shoots and falls to the correct reading, or bounces around?I don't have a schematic for that model but I'll throw out some basic stuff based on other Fluke models, maybe it will give you ideas. In DCV mode, the input should be coming in through a 10Meg resistor straight into the ADC. For 5V range, I'm guessing the divider would be in 1/10 mode, meaning the controller will bridge the input via an internal switch to a 1.111Meg resistor, the other end of which is grounded (probably in common with the other values necessary for 1/100, 1/1000, etc.) All these should be on the thick-film resistor array on the LCD side of the board.I can't quite imagine what sort of fault there would create a time constant slow enough to observe, but hey, have a look at that divider resistor array. If the symptom only occurs on the 5V range, then it seems to be the likely spot for something to go wrong.

author: bdivi
author_rank: Regular Contributor
timestamp: December 10, 2013, 07:16:26 am
content: Thank you ModemHead,When I say slow settle I mean it rises quickly to within 50-100mV bellow the measured value and then takes a couple of seconds to reach the final value. Just like charging a capacitor, no overshot whatsoever.I also noticed that the meter is somewhat slow with the continuity beeper - again next to 187 that never misses.All other modes and ranges are much quicker but when I carefully compared to the 187 side by side the 89 takes a couple of cycles to settle like charging a capacitor.Overall it looks like an RC time constant that is larger and most visible in the 5V range.Schematics of similar Fluke meters would helpCheers

author: ModemHead
author_rank: Frequent Contributor
timestamp: December 10, 2013, 11:57:10 pm
content: Quote from: bdivi on December 10, 2013, 07:16:26 amThe first-generation 80 series have full schematics in the service manual. These models are old, but the section at the end includes "signal flow" diagrams that are instructional, and not all that different from many models. It's too bad that service manuals and real schematics are a thing of the past.http://assets.fluke.com/manuals/83_85_87smeng0500.pdfAs to your problem, I'm not sure what to recommend. Maybe check the input impedance for anomalies? This 189 I have here measures 10.998Meg on the 5V DC range. It will go down as the ranges go up, as the controller switches in smaller resistors for the bottom end of the divider.

author: retiredcaps
author_rank: Super Contributor
timestamp: December 11, 2013, 07:54:16 am
content: Another long shot. Looking at modemhead's 189 pictures, I see three green 100kohm resistor which may or may not be power resistors to limit current for input protection. You may want to verify they are indeed 100kohm?

author: retiredcaps
author_rank: Super Contributor
timestamp: December 14, 2013, 10:46:38 pm
content: I got a new to me 89IV and just tried measuring a simple 1.5 AA cell. I am noticing the same slower settle time compared to a 187.I guess we will have to see if more 89IV owners report the same or not?

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: December 15, 2013, 12:21:15 am
content: Do you notice any difference if you disable autoranging?

author: retiredcaps
author_rank: Super Contributor
timestamp: December 15, 2013, 05:39:17 am
content: Quote from: ManateeMafia on December 15, 2013, 12:21:15 amNo difference in auto or manual range (5V range). If it isn't obvious, this is in the 50,000 count mode.The 89IV seems to display five to seven readings before settling on the "correct" one. It doesn't overshoot at all, it just takes time to "ramp up" to the correct reading. It is like smoothing mode is enabled or something?I'll try to take a video over the next couple of days and go frame by frame so I can get the exact number of readings.

author: bdivi
author_rank: Regular Contributor
timestamp: December 15, 2013, 08:05:55 am
content: That is exactly what I see as well - some sort of smoothing in software I guess because I do not see any capacitor.The questions here is why only the 5V range ?Fluke on the other hand responded in a mail that this slow settle should not be normal.==========Good Morning,8Xiv series was replaced by the 18X series in October 2000, the two series are very similar apart from the PC interface being slightly different. I have asked the service team who have researched their knowledge base and there is nothing to indicate that the slower response you have noticed has been reported as an issue.RegardsPhil SabbertonFluke UK Tech Support

author: AndyC_772
author_rank: Super Contributor
timestamp: December 15, 2013, 08:44:45 am
content: Quote from: retiredcaps on December 14, 2013, 10:46:38 pmI have an 89IV, and I'm afraid the symptoms described don't apply to my meter. The continuity beeper is extremely fast, and there doesn't seem to be any real difference in settling time between ranges.It looks as though the meter takes about 3 readings to fully settle. The first reading after connecting a voltage source is low, which is exactly what I'd expect given the fact that it's going to be averaging the voltage over the whole of the sample period. The second reading is almost spot-on, give or take a few counts, and the third is the final, stable reading which it will maintain indefinitely.

author: bdivi
author_rank: Regular Contributor
timestamp: December 15, 2013, 10:56:56 am
content: Here is a video of the 89IV and 187 meters side by side.The first part is 2V slow motion x0.25 were the difference is clearly seen - the 187 takes less than a second to stabilize and the 89 needs 3-4 seconds to do the same. You can notice the same problem when going from 2V down.I also captured the same 2V in the mV range - no difference whatsoever. Same for 20VInteresting !

author: AndyC_772
author_rank: Super Contributor
timestamp: December 15, 2013, 11:42:44 am
content: My 89IV behaves just like your 187.

author: Robomeds
author_rank: Frequent Contributor
timestamp: December 15, 2013, 03:36:46 pm
content: I'm going to have to check my 89IV the next time I get a chance. I don't recall noticing that it was slow in any range but I haven't used it that much.

author: retiredcaps
author_rank: Super Contributor
timestamp: December 15, 2013, 07:02:12 pm
content: I don't see a way to display the firmware level of the 89IV so can people please list the first 4 digits of their serial number? Maybe Fluke made a firmware change to get rid of the "smoothing" mode?

author: retiredcaps
author_rank: Super Contributor
timestamp: December 15, 2013, 07:06:07 pm
content: Quote from: bdivi on December 15, 2013, 10:56:56 amSince you already have a case/dialog with Fluke technical support, can you point them to this thread and your video so they can see the problem first hand?The chances of your 89IV being "broken" due to a bad component is now remote since I have the same smoothing behaviour and we are both in different parts of the world and probably acquired our meters in totally different ways.I'm now suspecting they made a firmware change?

author: retiredcaps
author_rank: Super Contributor
timestamp: December 15, 2013, 07:12:19 pm
content: Quote from: bdivi on December 15, 2013, 10:56:56 amYou can also see in your video, the 89IV displays 8 readings before getting to 2.0035, whereas the 187 displays 3 readings to get to 2.0034.At 4/sec display update (as per manual), that suggests the 89IV takes 2 full seconds (at least) to display 2.0035 and the 187 takes 0.75 seconds to display 2.0034.The 89IV 8 readings: 0.3884, 1.5171, 1.8709, 1.9672, 1.9935, 2.0025, 2.0031, 2.0035.The 187 3 readings: 0.8376, 2.0031, 2.0034.PS. Great video capturing the behaviour.

author: dtmf
author_rank: Newbie
timestamp: July 26, 2014, 12:18:33 pm
content: I have the same problem with 89IV and 5v range.Any solution?Fluke 87 III is 2 times faster.

author: daddario
author_rank: Regular Contributor
timestamp: July 27, 2014, 07:52:08 pm
content: My 89IV is also slower than, for example, my old 85III, even in 5000 count mode. But not several seconds slow and nothing exclusive for the 5V range.What's more irritating, is the slow continuity buzzer with its silly chirping sound. I mean, it's still fast, but not quite as gripping as any other "true" 80-series I've ever used. I can without a problem persistently grate my probes together without the meter making a single beep.

author: bdivi
author_rank: Regular Contributor
timestamp: July 27, 2014, 09:25:19 pm
content: Continuity also seems to be slower on my 89IV compared to 187.It looks like the 187/189 has improved over 89IV after all.Anyway now that I know it is not my meter fault I am using it for current measurement as my second meter.

author: AndyC_772
author_rank: Super Contributor
timestamp: July 28, 2014, 07:43:08 am
content: Do you know your 89IV firmware version?My (fully working) meter has version 2.02. You can find this out by downloading any logged data to your PC via the IR port into FlukeView Forms, if you have these. Not sure if there's any other way.

author: fergch
author_rank: Contributor
timestamp: August 30, 2015, 10:00:30 pm
content: There's another way: hold the RANGE button when you power on, the firmware shows on the screed for a second or two so keep watching. (mine is 2.02)...

author: kamcm
author_rank: Regular Contributor
timestamp: February 21, 2016, 03:39:03 pm
content: Mine is V1.01 .Having the same problem.SUPER SLOW TO SETTLE DOWNWhere can I get the latest firmware?Please advice,Thanks.

author: bdivi
author_rank: Regular Contributor
timestamp: April 20, 2016, 03:24:43 pm
content: I can confirm mine is 1.01 as well - not sure if it can be reasonably upgraded.I guess we are stuck with what we have

author: retiredcaps
author_rank: Super Contributor
timestamp: April 20, 2016, 07:03:49 pm
content: I know no way of upgrading the firmware for the Fluke 87IV, 89IV, 187 and 189.The video clearly shows the problem. Getting Fluke to acknowledge it and fix it on a discontinued meter is the big challenge. Fluke's front line support people are likely too young and not experienced enough to even know what these models are.

author: rauldm
author_rank: Regular Contributor
timestamp: May 23, 2021, 04:00:24 pm
content: I compared my 87 IV with 289 fw 1.41, really is slow in 5 V range, I restored to factory defaults from fluke view forms, the meter behavior in 5 V range is same. Also I have a 87 III, this meter is to fast in 4000 counts mode, but 20000 counts mode is incredible slow compared with my 87V. I think is normal because are very old meters, today I have a DT4282 from hioki, is the more faster meter I have in DC mode and Ohms, if you want a faster meter with 50000 to 60000 counts, the DT4282 is right choosing. I have U1282A from keysight, is really slow compared with every my meters. Fluke 87 IV is aceptable for me, because is very robust meter, PCB it has very well build quality, my meter even works right the super capacitor, I sold a 289 because it had leakage in that capacitor, again I bought a 289 and comes with newer firmware and capacitor leakage solved (I think that it).I prefer the quality build of Fluke's from 2000's years, the 87 III and 87 IV are my favorites.Regards.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 23, 2021, 04:43:16 pm
content: I think you're gonna be stuck with this problem, the 187 and 189 are an evolution of the 87IV and 89IV ... every 189 i have or had fw2.02 ??The 5v range problem is known for quite some time and Fluke never acknowledged itOnly thing i know, someone here converted a 187 into a 189, maybe something is to be learned and maybe an fw transplant could work ??https://www.eevblog.com/forum/testgear/fluke-187-dmm-upgrade-to-189/Post #10 seems interesting ... reprogram the eeprom ??

author: retiredcaps
author_rank: Super Contributor
timestamp: May 23, 2021, 05:33:35 pm
content: Quote from: rauldm on May 23, 2021, 04:00:24 pmThe Fluke 87 series I, II and III update 1/sec in 20,000 count mode.

author: rauldm
author_rank: Regular Contributor
timestamp: May 23, 2021, 06:43:53 pm
content: 1 Hz update frequency in 20000 counts because is old architecture, the 87 IV and 89 IV also are around 1999 year, ok datasheet says 4 Hz, but the 18x series came with other hardware even USB189IR is not compatible with 8x IV series, perhaps is a hardware problem.