Some questions about buying a used fluke 87 III/V - Page 1
Forum section: electronics / beginners

author: doctorm
author_rank: Regular Contributor
timestamp: July 07, 2010, 09:54:20 pm
content: so ive been looking at ebay for a used fluke 87 and found some III's and V'si had posted a previous question about buying safely on ebay for a fluke and i got the hang of it but now i wanted to ask about what to do when i actually go the thing.i do have access to a physics lab with power supplies and such so i can test the meter out that way but if its messed up how much would it cost to calibrate the meter (if its either the III or V) and get back to working order? would it be wise to go ahead and get it calibrated or whatever anyways when i get it?there are some meters that do not come with leads and cases. how much would it usually cost to get them?do flukes hold up for a good period of time when being used? as in their readings are good and such if it looks and sounds like it wasnt terrible abused or used?What is the differnce between the fluke 87 III and the fluke 87 V? i wanted to make sure bc all i can remember is that hte V is just newer and thats it.if you have any other advice/suggestions i would appreciate. thanks

author: Unknown
author_rank: Unknown
timestamp: July 07, 2010, 10:21:42 pm
content: I think Fluke wants something like $120 or so for calibration, I'd guess something like $75-$125. That's probably a significant part of the price, so I would see if it's not really off and try to compare it with other meters (preferably calibrated), as long as it's reasonably close, I'd assume it's fine. Fluke meters usually don't drift much unless something's damaged. Leads can be had for a few dollars (but quality ones like the original Fluke ones are more expensive). I wouldn't use the really cheap ones for dangerous voltages like mains, but they're probably fine for extra low voltage stuff. Re case, if you mean the rubber holster, check Ebay. If you mean a leather/fabric case, anything that fits (like a case to carry an external hard drive) will be fine, so you can probably find something cheap locally.Search the forum for the differences between the various versions, there has been a fair amount written about it. From memory, the version V has a nicer display/backlight, probably fixed the zebra contacts issue, and add some features that in my opinion are of minor importance for non-industrial work, like a low pass filter for variable frequency motor drivers.

author: RayJones
author_rank: Frequent Contributor
timestamp: July 07, 2010, 10:54:01 pm
content: Does anybody know what is involved with Fluke's calibration?The reason I ask is other BIG test equipment manufacturers may offer a "calibration" service, but this is in reality simply confirming that your unit is within the published specification for that device.If found to be outside the published specs, the unit is deemed to have failed calibration, but if you offer more money they can then perform an adjustment...ie the calibration does not involving performing adjustments to the device.Worth bearing in mind, especially if you think your unit freshly returned from calibration is now spot on.

author: Unknown
author_rank: Unknown
timestamp: July 07, 2010, 11:46:46 pm
content: According the European procedures, Fluke will adjust the equipment (if possible) if it's at least 70% out of tolerance, at least for the cheapest level (which is all you need as hobbyist), there is a higher level which doesn't provide adjustment, probably for companies doing their own characterization. From the US offerings, it looks like everything except a performance test provides adjustment.

author: saturation
author_rank: Super Contributor
timestamp: July 07, 2010, 11:53:03 pm
content: To add to prior posts, Fluke provides the calibration and adjustment manuals for the 80s series, you can download it off their site. Its very detailed and describes what voltage, signal etc., sources you need and its rated accuracy.One of the benefits of the III ?? [ maybe 4] and up versions, is adjustment are all electronic and can be done through the front controls, the older generation 1-2 [ maybe up to 3??] have pots than need tweaking with a screwdriver.The adjustments are very straightforward, you very likely cannot destroy the meter like you would hacking the Rigol 1052E.Essentially you set the voltage source to e.g. 12.34V dc, and if you meter doesn't read 12.34, adjust XYZ until it does. Repeat for various ranges.Fluke leads are ~ $20-30 new, but they are rebadged Pomona, and for CAT III and below use, you can find them for < $20.Cases can be bought eBay for ~< $20 or bought new from the Fluke store.My 85 remains accurate in V DC, AC and ohms uncalibrated since 1989. I know this because I recent got hold of a NIST calibrated DMM, and a frequency source and compared it. I certainly didn't expect it to be this accurate 20 years later.III vs VQuote from: doctorm on July 07, 2010, 09:54:20 pm

author: EEVblog
author_rank: Unknown
timestamp: July 08, 2010, 02:38:52 am
content: BTW, a quick test to help ensure your Fluke is still accurate and working is to probe the uA/mA socket while on ohms. It should read pretty close to spot on 1KUseful if doing a quick inspection before buying 2nd hand or whatever, or asking an ebay seller to do who "doesn't know how to test these things"Dave.

author: Time
author_rank: Frequent Contributor
timestamp: July 08, 2010, 03:48:55 am
content: Is this going to ensure the accuracy and functionality of all the functions or simply the resistance measurement?Quote from: EEVblog on July 08, 2010, 02:38:52 am

author: EEVblog
author_rank: Unknown
timestamp: July 08, 2010, 04:47:20 am
content: Quote from: Time on July 08, 2010, 03:48:55 amNo, but it tells you that the reference voltage is spot on, and probably part of the precision resistor network as well. As it's unlikely that the current shunt resistor would drift in the opposite direction to the voltage reference reference and give you a "false positive" reading for example.I'd be very surprised if you could have resistance measure spot on and voltage be out of spec for example (in a fluke, other meters may vary).Dave.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: July 08, 2010, 06:45:57 am
content: I like to believe that the auto-range DMM are easy to check for accuracy.If its off in one range , its off to all .But even if I got from ebay as " Calibrated " my Fluke 8050A , I liked to had my own little gadgets,that would verify basic accuracy and stability .One tricky point about the Fluke 87 are the Fuses ,by studying a bit this matter , found that every Fuse type has its own internal resistor.If the meter comes with the genuine Fuses , it stays accurate even just from that.As the resistor of the specific fuse - fuses , was known at themaster( factory )calibration - adjustment .( I had become as expert in all those , but I had no choice , now I own 8 meters ..)

author: Excavatoree
author_rank: Frequent Contributor
timestamp: July 08, 2010, 02:43:12 pm
content: Quote from: EEVblog on July 08, 2010, 02:38:52 amOne more thing I should have been able to derive myself. Oh well.Dave, would you allow me to add this check to my Ebay Fluke guides?

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: July 08, 2010, 06:45:16 pm
content: At my 87-5 ( V )I get 1001 at uAAnd 0.2 at AmperesOne Tip for all, touch the lead at the inner upper area at the leads hole ..Just at the very begging of the hole ..Or else you will get LEAD alarm and 1.5 MOhm readings ..

author: Excavatoree
author_rank: Frequent Contributor
timestamp: July 08, 2010, 06:56:52 pm
content: Quote from: Kiriakos-GR on July 08, 2010, 06:45:16 pmThat's a good point. If one is asking an e-bay seller, who may be inexperienced, to do this check, it's probably better to plug the negative lead in the current jack and touch the leads together. (then they will get confused, plugging the black lead in the red jack, and you can explain that the current doesn't care.)When I get home from work, I'll have to see the resistance of the current shunts in other models.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: July 08, 2010, 07:16:01 pm
content: Quote from: Excavatoree on July 08, 2010, 06:56:52 pmSorry but you sound as a bit inexperienced your self ..If you plug any lead at the " uA Amp " ranges at the Ohm scale , you get LEAD alarm on the spot.Touching the Positive lead ( Ohm ) at the " uA Amp " ranges as I described above,are the only way to do this test.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: July 08, 2010, 07:34:04 pm
content: I've got two or three blown fuses that say I ignore lead warnings.For the 87-III and earlier - you can still read the resistance on the screen, you just have to ignore the beeping. (I have only a 87-III at work, so that's all I can check at the moment. Despite the beeping, I can still read 1.003 K.) So my experience isn't as lacking as you might think.Only the newer meters display "lead" and prevent you from reading this resistance. (I rarely use my 87-5) Some of the lower end meters will simply flash "lead" when you change from current to something else, or vice-versa, but only for a second or two, you can still read the resistance."Back in my day, we didn't have "lead warnings," and we LIKED it."

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: July 08, 2010, 09:00:55 pm
content: Quote from: Excavatoree on July 08, 2010, 07:34:04 pmBack in my day, we was riding dinosaurs ,butwe do not do that any more ,it damages the highway ..

author: Unknown
author_rank: Unknown
timestamp: July 08, 2010, 09:24:17 pm
content: Quote from: Kiriakos-GR on July 08, 2010, 09:00:55 pmPlus the fuel probably got too expensive.Quote from: EEVblog on July 08, 2010, 04:47:20 amNice way to test basic voltage measurement, the current source for resistance measurements, and the internal low-current shunt. The main things it misses are parts of the divider network, both for resistance and for voltage, and the 10A shunt. I do occasionally see meters with defects like dead high resistance ranges or a dead voltage range, but you have to cycle through the all ranges with something like a battery and a resistor to test those. Another possible issue is the calibration constants (eg. some idiot messed with the calibration), these are fixable, but might almost double the price if you got the meter for something like $100. These are often separate for each range and function, so you have to test all ranges for those.I try to do a full performance verification according to the service manual after I receive something (so I can complain) or if I pick it up. It might annoy the seller, but if you sell something as-is, I'm going to do my best to figure out any faults before giving you my money. It depends on the price, I'm willing to take more risks if it's cheap enough.

author: EEVblog
author_rank: Unknown
timestamp: July 08, 2010, 10:20:23 pm
content: Quote from: Excavatoree on July 08, 2010, 02:43:12 pmNo problemo.Dave.

author: EEVblog
author_rank: Unknown
timestamp: July 08, 2010, 10:28:00 pm
content: Quote from: Kiriakos-GR on July 08, 2010, 07:16:01 pmNo, you can do it as Excavatoree said. Yes, the meter beeps at you and shows "LEAD", but it also alternates the display between the actual reading.Mine shows 0.9985K, not quite spot-on.Dave.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: July 09, 2010, 12:15:50 am
content: Ok my last attempt to express my self .. correctlyQuoteDo we agree here ... ?QuoteIts best to check your battery first , and then to do the test.

author: EEVblog
author_rank: Unknown
timestamp: July 09, 2010, 02:14:58 am
content: Quote from: Kiriakos-GR on July 09, 2010, 12:15:50 amNo, I do not agree, you are incorrect.Itispossible to plug the lead into the uA/mA jack and measure resistance at the same time as I have stated. It is just annoying because it alternates the display and beeps at you.Dave.Dave.

author: saturation
author_rank: Super Contributor
timestamp: July 10, 2010, 11:58:24 am
content: Tried it, I get 1003, or +0.3% off assuming 1000 is right.Dave's value is actually better, 998.5 is -0.15% off 1000.Quote from: EEVblog on July 08, 2010, 10:28:00 pm

author: darrenb
author_rank: Contributor
timestamp: May 12, 2012, 06:25:38 pm
content: I get 1.003 which seems correct as there are about 0.2 - 0.3 ohms resistance in the leads (Fluke 87 V)

author: eevblogfan
author_rank: Frequent Contributor
timestamp: May 12, 2012, 07:48:52 pm
content: mine 278 - 9,997 ohm ? ( on 0.025% meter I get 3 count out , and on the 0.05% I get 5 count out ? wierd ! )the 87V - on 6000 count- 1,000 ohm (spppot on)on 20,000 count - 10,005 ohm (and it is used and I dont know what is the age , but I think it is a few years old )have a nice day !

author: Unknown
author_rank: Unknown
timestamp: May 12, 2012, 11:52:12 pm
content: Note that while this is a decent test of basic functionality, you should not consider this a way to test its accuracy down to the last digit. There is no reason for Fluke to tightly control the shunt value. Any stable value will do: they can easily compensate for any value by changing the cal constants.

author: eevblogfan
author_rank: Frequent Contributor
timestamp: May 13, 2012, 04:26:23 am
content: thanks ,yep I know, but it;s still fun to look at this numberespeccialy when compare to my 287 , I am getting only 2 count diffrnce , while comparing the reading (paralel ) I get the same current esacly ( the 87 read like a 0.1767 while the 287 read 0.1767 abit faster )BTW , if the resistance of the percsision resistor changes via the tem'p , canno't we compenset that via thermistor/thermo couple ? (IE , define that every 0.1C = 0.02ppm to add or something like this ..)or there is somthing like this ? if so . whats the name of it ?thank you in advance !

author: M. András
author_rank: Super Contributor
timestamp: May 13, 2012, 08:06:04 am
content: checked my 289 for curiosity, the 400ma socket reads 9.998/9k, the 10 amp socket reads 0.08ohm

author: eevblogfan
author_rank: Frequent Contributor
timestamp: May 13, 2012, 11:20:15 am
content: mine 287 was flikering between 9,998~7 . so I posted here 9,997

author: Unknown
author_rank: Unknown
timestamp: May 13, 2012, 01:08:46 pm
content: Quote from: eevblogfan on May 13, 2012, 04:26:23 amThis trick is used by TCXOs (temperature compensated crystal oscillators). Sometimes components with an opposite tempco are used in series to decrease the net tempco. The trouble with sensing the shunt resistor temperature is that you need to measure the resistor temperature accurately. Since the resistor is dissipating power, its core will always be hotter than its case. You could model this with the thermal resistance, but it's probably more trouble than it's worth, a more expensive resistor with a lower tempco is probably cheaper. Putting the shunt resistor in an oil bath appears to be more common, but is not very practical in a handheld meter.

author: jonsig
author_rank: Contributor
timestamp: May 16, 2015, 03:00:39 am
content: Sorry about resurrecting this interesting thread . But i cant seem to find the date of manufacture for the 87-series 3 .BTW mine reads 1003 ohms / 1002.8 in hi -res via µA socket.

author: retiredcaps
author_rank: Super Contributor
timestamp: May 16, 2015, 03:26:31 am
content: Quote from: jonsig on May 16, 2015, 03:00:39 amUser manual has a copyright date of Oct 1997 suggesting the first III series was likely introduced sometime in 1997.

author: retiredcaps
author_rank: Super Contributor
timestamp: May 16, 2015, 03:31:31 am
content: Teardown pictures of the 87 III athttps://www.eevblog.com/forum/testgear/fluke-87-iii-pictures!/suggest year 1998 week 14 on the main IC supporting the theory that the manual dated Oct 1997 is likely correct.

author: jonsig
author_rank: Contributor
timestamp: May 16, 2015, 11:26:41 pm
content: Sorry , but its a problem with your link .Yeah i read that 87 -3 switched background light in the meantime . First 87-3 models had green ,battery destroying back light .My unit has blue-white´ish back light . Wonder if it´s late model .

author: mos6502
author_rank: Frequent Contributor
timestamp: March 08, 2016, 04:34:03 pm
content: Quote from: jonsig on May 16, 2015, 11:26:41 pmWait, what? Can anyone elaborate on this? Why is it battery destroying?I just checked the 87-III service manual, and it only mentions "Backlight, White" in the parts list ...FYI, my 87-V (manufactured in 2014) reads 1.0015.

author: ericloewe
author_rank: Unknown
timestamp: March 08, 2016, 09:52:44 pm
content: Quote from: mos6502 on March 08, 2016, 04:34:03 pmPresumably because it uses a crapton of power.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 09, 2016, 01:29:33 am
content: Quote from: mos6502 on March 08, 2016, 04:34:03 pmEarlier/inital versions of the 87 III used a green colored backlight. Later versions switched to a white backlight which reduced battery consumption.

author: mos6502
author_rank: Frequent Contributor
timestamp: March 09, 2016, 04:09:27 am
content: Quote from: retiredcaps on March 09, 2016, 01:29:33 amOK, but why? A green LED doesn't draw much more power than a white LED. Or is the green Fluke backlight EL based?I bought an 87-III that is due to arrive today ... interestingly the photos in the listing didn't show the backlight.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 09, 2016, 07:16:57 am
content: Quote from: mos6502 on March 09, 2016, 04:09:27 amEbay seller a-fluke, had a listing, that described the difference between the two and why? I don't see a listing from him at this moment.I can't test because I don't have a 87 III.

author: mos6502
author_rank: Frequent Contributor
timestamp: March 09, 2016, 07:51:07 am
content: Quote from: retiredcaps on March 09, 2016, 07:16:57 am<google-fu> You mean this guy?http://stores.ebay.com/Multimeters-and-AccessoriesI found this listing:http://www.ebay.com/itm/Fluke-87-88-Multimeter-WHITE-LED-Back-Light-Upgrade-Conversion-Module-Kit-/371548347489?hash=item568201dc61He claims the green backlight is incandescent? Whaaat? That makes no sense. The 87-III is from when, the late 90s/early 2000s? Green LEDs were around then. In fact much earlier. It would make zero sense for Fluke to use incandescent bulbs. Also, in his photo, you can see that the backlight consists of four light sources. If they used light bulbs, they wouldn't have usedfourof them. On top of that, an incandescent backlight wouldn't be green, unless they painted the bulbs green.My meter is going to arrive in a few hours. If it has the green backlight, I'll do some current measurements, take it apart and check it out.

author: mos6502
author_rank: Frequent Contributor
timestamp: March 09, 2016, 09:36:42 am
content: So the 87-III just arrived. Too bad, it's a white backlight.By the way, it does NOT turn off automatically, just like on the 87V. It only has one brightness level, though (about as bright as the high level of the 87V). I also did the resistance check aginst the mA jack: 1.0012k.

author: ModemHead
author_rank: Frequent Contributor
timestamp: March 09, 2016, 12:46:00 pm
content: This is an incandescent backlight module from an original 87 (circa 1990). Sorry for the bad focus, I'm in a bit of a hurry here. Not sure where the green color comes from, it's sealed up and I don't wish to break it.It draws 60mA at 8.5V.Edit:To be honest, the only reason I called it incandescent is because I had it in a container labeled "old 87 incandescent backlight module". I just did a quick test and it draws practically no current until a knee when the terminal voltage reaches 3.0V. Which sounds more like there's actually some arrangement of LEDs on the other side. In any case, it is a power hog.

author: mos6502
author_rank: Frequent Contributor
timestamp: March 09, 2016, 04:27:20 pm
content: Thanks man, very interesting. Are you a-fluke on eBay?Obviously it's 2x2 green LEDs in series at 30 mA each. You could probably replace those 130 ohm resistors with 1k ones and it would still be bright enough. Do you know if the models with the green backlight have a backlight timer?One downside I found is that the 87-III doesn't sound the beeper in diode test mode. Bummer.The different bargraph types of the 87-III vs the 87-V are also curious ...

author: ModemHead
author_rank: Frequent Contributor
timestamp: March 09, 2016, 05:05:15 pm
content: Quote from: mos6502 on March 09, 2016, 04:27:20 pmNope, not a-fluke. Although I did get a new backlight module from him for my old 87 a few years ago, and that's probably the reason I labeled the old one "incandescent" when I stored it away.My original 87 has a 60-second backlight timer. And annoyingly, you can only turn itonwith the button. The whole meter has to be turned off to get the backlight off early.And yes, those resistors are wasting a ridiculous amount of power.

author: Wytnucls
author_rank: Super Contributor
timestamp: March 09, 2016, 05:25:51 pm
content: The Fluke 185 has a similar green backlight consisting of 7 LEDs, with one, mercifully, left unpopulated.Current draw goes from 16mA to 160mA, with the green backlight ON (2 AA batteries).

author: mos6502
author_rank: Frequent Contributor
timestamp: September 26, 2016, 09:47:45 pm
content: Alright, I recently got a Fluke 88 (original series, with green backlight) and I wanted to get to the bottom of this. I measured the battery drain. Here are my findings:Fluke 88 (green BL)Fluke 87 III (white BL)Fluke 87 V (white BL)off9.6µA8.6µA0.1µAVDC760µA920µA1.15mAVDC, BL on22mA26mA9.18mA (Level 1), 21.2mA (Level 2)So much for "battery destroying". Another myth busted. Plus, the green actually looks cooler.Edit: added data for 87 V.No idea if the larger off-state drain of the older meters is due to aging (carbon from the switch causing leakage current) or due to the circuit design. IMHO it must be the latter, because all 3 meters measure within 2 counts of each other (quick check with a 9V battery: 87 V says 9.033, 87 III says 9.031, 88 says 9.032) , I think internal current leaks would have an effect on the calibration.Edit 2: ah, found it. The older 80 series have a signal called PDS (power down signal) that is connected to VBT+ and in the off state is pulled down to VBT- through a 1M resistor. So all the older 80 series will have an off state drain of around 9 microamps. It's all good.

author: BMack
author_rank: Regular Contributor
timestamp: September 27, 2016, 02:18:41 am
content: Quote from: mos6502 on March 09, 2016, 04:27:20 pmI didn't know about this before I bought it either...so I bought another 87V and eventually I'll be getting around to listing the 87 III, not just for that but another knock(don't like the holster, capacitance, temp) it's harder than I thought to adjust to the limited feature set.In some light I do like the green light more but most of the time I prefer the white. At least it isn't orange like Agilent/Keysight, that is soo weird to me.

author: mos6502
author_rank: Frequent Contributor
timestamp: September 27, 2016, 12:15:16 pm
content: The 87 III does have some features that the 87 V is missing. The autoranging is much faster. But the main thing is, the 87 III's bar graph (actually an analog pointer) has 6 times the resolution of the 87 V's bar graph (1000 counts full scale vs. 6000 counts full scale). I'll keep mine for that reason alone.In the original 80 series, the 83, 87 and 88 all had different LCDs. The 83 had a regular bar graph that is just a full scale reading of the current range. The 87 had the high resolution analog pointer (4000 counts, wrapping four times for each range). The 88 had yet another type, a 2000 count analog pointer, wrapping twice per range. So the high res pointer was actually a big feature that distinguished the 87 from the cheaper 83.Probably to save money in production, on the 80 V series, the 83 V, the 87 V and the 88 V all use the same LCD. So you only get the regular 6000 count bar graph.