Author Topic: Some questions about buying a used fluke 87 III/V  (Read 10776 times)

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Offline doctorm

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Some questions about buying a used fluke 87 III/V
« on: July 08, 2010, 07:54:20 AM »
so ive been looking at ebay for a used fluke 87 and found some III's and V's

i 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

alm

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Re: Some questions about buying a used fluke 87 III/V
« Reply #1 on: July 08, 2010, 08:21:42 AM »
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.

Offline RayJones

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Re: Some questions about buying a used fluke 87 III/V
« Reply #2 on: July 08, 2010, 08:54:01 AM »
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.

alm

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Re: Some questions about buying a used fluke 87 III/V
« Reply #3 on: July 08, 2010, 09:46:46 AM »
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.

Offline saturation

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Re: Some questions about buying a used fluke 87 III/V
« Reply #4 on: July 08, 2010, 09:53:03 AM »
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 V



so ive been looking at ebay for a used fluke 87 and found some III's and V's

i 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
« Last Edit: July 08, 2010, 09:59:35 AM by saturation »
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Saturation

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Re: Some questions about buying a used fluke 87 III/V
« Reply #5 on: July 08, 2010, 12:38:52 PM »
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 1K
Useful 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.

Offline Time

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Re: Some questions about buying a used fluke 87 III/V
« Reply #6 on: July 08, 2010, 01:48:55 PM »
Is this going to ensure the accuracy and functionality of all the functions or simply the resistance measurement?

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 1K
Useful 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.
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Re: Some questions about buying a used fluke 87 III/V
« Reply #7 on: July 08, 2010, 02:47:20 PM »
Is this going to ensure the accuracy and functionality of all the functions or simply the resistance measurement?

No, 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.

Offline Kiriakos-GR

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Re: Some questions about buying a used fluke 87 III/V
« Reply #8 on: July 08, 2010, 04:45:57 PM »
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 the master ( factory ) calibration - adjustment .

( I had become as expert in all those , but I had no choice , now I own 8 meters ..  :D  )
    

Offline Excavatoree

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Re: Some questions about buying a used fluke 87 III/V
« Reply #9 on: July 09, 2010, 12:43:12 AM »
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 1K
Useful 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.

One 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?


Offline Kiriakos-GR

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Re: Some questions about buying a used fluke 87 III/V
« Reply #10 on: July 09, 2010, 04:45:16 AM »
At my 87-5  ( V )

I get  1001 at uA
And  0.2 at Amperes 

One 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 ..  

Offline Excavatoree

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Re: Some questions about buying a used fluke 87 III/V
« Reply #11 on: July 09, 2010, 04:56:52 AM »
One 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 ..  

That'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.

Offline Kiriakos-GR

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Re: Some questions about buying a used fluke 87 III/V
« Reply #12 on: July 09, 2010, 05:16:01 AM »
plugging the black lead in the red jack, and you can explain that the current doesn't care.)

Sorry 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.
« Last Edit: July 09, 2010, 05:18:44 AM by Kiriakos-GR »

Offline Excavatoree

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Re: Some questions about buying a used fluke 87 III/V
« Reply #13 on: July 09, 2010, 05:34:04 AM »
I've got two or three blown fuses that say I ignore lead warnings. ;D

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."

« Last Edit: July 09, 2010, 05:42:24 AM by Excavatoree »

Offline Kiriakos-GR

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Re: Some questions about buying a used fluke 87 III/V
« Reply #14 on: July 09, 2010, 07:00:55 AM »

 "Back in my day, we didn't have "lead warnings," and we LIKED it."


Back in my day, we was riding dinosaurs , but we do not do that any more ,
it damages the highway ..   ;D
« Last Edit: July 09, 2010, 07:43:41 AM by Kiriakos-GR »


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