Author Topic: Fluke 87V or the 179 vote on Twitter.  (Read 5850 times)

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Online xavier60

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #75 on: November 28, 2020, 12:47:25 pm »
I can accept that Diode test beeps are not important to all.
Has anyone objected to their DMM having Diode test beeps?
Brymen has added Diode test beeps to some models.
Earlier, would have been more useful to me.
There was plenty of time to copy the idea from Fluke.
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Offline 2N3055

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #76 on: November 28, 2020, 01:17:04 pm »
I can accept that Diode test beeps are not important to all.
Has anyone objected to their DMM having Diode test beeps?
Brymen has added Diode test beeps to some models.
Earlier, would have been more useful to me.
There was plenty of time to copy the idea from Fluke.
Well that is the point. ALL other manufacturers could have copied it in 20 years, but none bothered. It seems, that for most users, that is "Oh that's kinda nice, but not really important" feature...
I had 73/III for many years, and never really used Touch hold much, or found that it diode beep mode was something I couldn't live without it.
As I said, even with the beep, I always check the voltage on the screen anyways..
But I totally understand that is how you got used to work...
 
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Offline Arhigos

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #77 on: November 28, 2020, 01:45:45 pm »
After deciding not to use my Brymen BM857S as my primary bench meter, I found myself missing the Hellboy red holster.
I purchased a used 87V EX for its holster. The meter turned out to have faults but is still useful as a field DMM, tractor repairs mainly.
The holster turned out to have a problem also. Its material is much softer than the standard yellow holster and is rather brittle.
It has cracked where the tilt bail attaches allowing it to swing out too far.
Do other  87V EX owners notice the same problem with the holster?
I have asked Fluke to make available red replacement holsters or the 87 series.

But this is just regular 87V in red holster on your photo.

87vEX looks different
 

Online xavier60

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #78 on: November 28, 2020, 01:48:24 pm »


But this is just regular 87V in red holster on your photo.

87vEX looks different
Have you seen it available for purchase?
And yes, I put one of my 87V DMMs into the red holster, works fine and looks wonderful.
« Last Edit: November 29, 2020, 01:28:57 am by xavier60 »
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Offline bdunham7

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #79 on: November 28, 2020, 06:21:03 pm »
Fluke 289....we got one....
I don´t like this....Booting time after power it on ...wtf?!
Fully overloaded with features, irritating menu structure - I just want to have a meter, power it on and measure something.

Boot time is 7 seconds, which shouldn't be intolerable.  Overloaded with features?  Yes, it is way overkill for most normal use, but hardly something to complain about.  Menu structure?  Yes, it takes a pretty astounding number of button presses to do certain things and it doesn't seem at all intuitive to me, so deduct some points for that.  But clearly it makes up for it with its light weight and compact size!  :-DD

Seriously, the only gripe I have is the lack of an internal thermocouple--even the Harbor Freight Cen-Tech models have that.  That and a Qi-powered lithium battery pack would pretty much bring it up to date.
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit DMM is good enough for most people.
 

Offline HKJ

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #80 on: November 28, 2020, 06:31:02 pm »
Boot time is 7 seconds, which shouldn't be intolerable.  Overloaded with features?  Yes, it is way overkill for most normal use, but hardly something to complain about.  Menu structure?  Yes, it takes a pretty astounding number of button presses to do certain things and it doesn't seem at all intuitive to me, so deduct some points for that.  But clearly it makes up for it with its light weight and compact size!  :-DD

In daily use the boot time is a PITA and the menus are not as fast as a SELECT button, but way more flexible.

Seriously, the only gripe I have is the lack of an internal thermocouple--even the Harbor Freight Cen-Tech models have that.  That and a Qi-powered lithium battery pack would pretty much bring it up to date.

No DMM has an internal thermocouple, but all (as far as I know) has a internal temperature sensor. Some meters will automatic show internal temperature with no thermocouple connected, with other meters (Like Fluke) you need to short the inputs.
I do not like LiIon battery packs, they basically limits the lifetime of the meter, because it is hard to get replacement after a couple of years. I could work around that, but AA is easier.
 

Offline bdunham7

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #81 on: November 28, 2020, 07:02:57 pm »
No DMM has an internal thermocouple, but all (as far as I know) has a internal temperature sensor. Some meters will automatic show internal temperature with no thermocouple connected, with other meters (Like Fluke) you need to short the inputs.
I do not like LiIon battery packs, they basically limits the lifetime of the meter, because it is hard to get replacement after a couple of years. I could work around that, but AA is easier.

Well there it is!  And pretty accurate, too.  I guess I should RTFM...

I doubt that lack of replacement battery packs would be an issue with Fluke, but the way it is constructed the Li-ion pack could be an option, or you could use AA NiMh.  It is the wireless charging that would be a great feature--and if it didn't cause too much interference, you could have infinite battery life and leave the meter turned on on the bench indefinitely.
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit DMM is good enough for most people.
 

Offline HKJ

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #82 on: November 28, 2020, 07:40:59 pm »
Well there it is!  And pretty accurate, too.  I guess I should RTFM...

I doubt Fluke explains it in the manual.

You can find a couple of technical articles about multimeters on my website: https://lygte-info.dk/info/indexArticles%20UK.html
I have one about thermocouplers where I cover the basics (For some people it may be way beyond the basics).
 
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Offline Arhigos

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #83 on: November 29, 2020, 01:53:28 am »


But this is just regular 87V in red holster on your photo.

87vEX looks different
Have you seen it available for purchase?
And yes, I put one of my 87V DMMs into the red holster, works fine and looks wonderful.

Only on second-hand market like ebay. 87ex was replaced by 28EX long time ago.
 

Offline james_s

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #84 on: November 29, 2020, 02:42:47 am »
Boot time is 7 seconds, which shouldn't be intolerable.  Overloaded with features?  Yes, it is way overkill for most normal use, but hardly something to complain about.  Menu structure?  Yes, it takes a pretty astounding number of button presses to do certain things and it doesn't seem at all intuitive to me, so deduct some points for that.  But clearly it makes up for it with its light weight and compact size!  :-DD

Seriously, the only gripe I have is the lack of an internal thermocouple--even the Harbor Freight Cen-Tech models have that.  That and a Qi-powered lithium battery pack would pretty much bring it up to date.


7 seconds feels like an eternity if I'm just trying to turn it on and take a quick measurement. I suppose a 18650 based battery pack could be nice for some use cases, although a big advantage of 9V and AA batteries is that in a pinch you can buy the disposable ones anywhere and I usually get several months out of the 9V in my 87-III before I swap it out with a charged one.
 

Offline tooki

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #85 on: November 29, 2020, 04:55:40 pm »
Well there it is!  And pretty accurate, too.  I guess I should RTFM...

I doubt Fluke explains it in the manual.

You can find a couple of technical articles about multimeters on my website: https://lygte-info.dk/info/indexArticles%20UK.html
I have one about thermocouplers where I cover the basics (For some people it may be way beyond the basics).
^^^ Your site has been an amazing resource for a long time. Just an expression of appreciation! (I also really appreciate the battery/charger info.)

FYI, the word is "thermocouple", not "thermocoupler". (I've noticed this error a few times on the site, too.)
 

Offline bayati

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #86 on: December 17, 2020, 02:44:01 pm »
I repair more than 10 different devices every day. I can't work without that diode beep anymore. If you have to check more than 100 Mosfets everyday you see how addictive that can be.
 
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Online Martin72

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #87 on: December 17, 2020, 10:13:47 pm »
You check MOS-FETs with diode test  ???
Interesting...
 
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Online xavier60

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #88 on: December 17, 2020, 10:37:45 pm »
A quick body diode and a G-S breakdown test will find just about all faulty power MOSFETs  and IGBTs, keeping in mind that not all IGBTs have diodes inside.
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Online Martin72

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #89 on: December 17, 2020, 10:49:59 pm »
Hm, doing it so will only find obviously defective ones, but there are several ways why a FET could be faulty.
 
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Online xavier60

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #90 on: December 18, 2020, 02:54:38 am »
Yes, transistors with subtle damage can be missed, to totally fail later. Hopefully it happens on the bench while taking extra precautions.
This doesn't happen very often as inverter bridge transistors often fail in high/low pairs
« Last Edit: December 18, 2020, 02:57:55 am by xavier60 »
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Offline 2N3055

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #91 on: December 18, 2020, 07:53:39 am »
Those transistors that failed to short, will activate classic continuity beep. Beep, OK that one's gone. Same as any discrete semiconductor.
Also like xavier60 says, in bridge, rarely they don't blow in pairs, but if it isn't cost prohibitive, I would change them in pairs even if one of fets looks OK.
It probably spent some time outside safe specs  and who know if all is OK.

Like Martin says, I will disconnect/pull out transistor and check it with tester to see. Even that is not real life test, but at least it is in isolation and you can check basic parameters.  Once I had soft starter for motors with large monolithic 3 phase FET bridge, that I improvised a jig that was testing it with 10A to see if it works ok. Small transistor tester from Atlas was showing nonsense...

If I had to check 1000 diodes a day, I would definitely think about if some specialized diode testing would do me good.

As I said, you should use any advantage that helps you do your job better and/or faster, depending on what is important.
I usually don't have to do things superfast, but it has to be right first time.

If you're changing 400€ 3phase MOSFET bridge on high power inverter, you won't plug it in to check if it's going to work now. You will check and measure 3-4 times and double check everything before power on. Sawing few minutes is not going to be priority..

So, yeah, like I keep repeating, it all depends on what you do, and what your methods are..

For my work, I simply use different troubleshooting technique, that doesn't benefit from diode beep mode, and it is not optimised for 100 transistors per hour but for something else.  I understand other people have different priorities..
 
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Offline Fungus

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #92 on: December 18, 2020, 10:00:56 am »
If I had to check 1000 diodes a day, I would definitely think about if some specialized diode testing would do me good.

This.

eg. Something that can automatically check the polarity both ways without swapping the leads around, etc.

 

Online xavier60

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #93 on: December 18, 2020, 10:23:29 am »
If I had to check 1000 diodes a day, I would definitely think about if some specialized diode testing would do me good.

This.

eg. Something that can automatically check the polarity both ways without swapping the leads around, etc.
The Fluke 18B+ sort of does that on its LED test range.
Open circuit, it outputs alternating 12v at 1.4Hz.
It stops alternating and gives a stable reading for drops between about 1 and 5 volts.
Although it keeps alternating for lower drops, the voltage can still be read.
« Last Edit: December 18, 2020, 10:25:08 am by xavier60 »
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Online Martin72

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #94 on: December 18, 2020, 09:27:40 pm »
Quote
eg. Something that can automatically check the polarity both ways without swapping the leads around, etc.

And reverse breakdown voltage...

Quote
in bridge, rarely they don't blow in pairs, but if it isn't cost prohibitive, I would change them in pairs even if one of fets looks OK.

Same here, at work(Power Inverter, Converter) and also at home (Audio Amplifiers).
Always in pairs, except IGBT Packs.. ;D

Quote
If you're changing 400€ 3phase MOSFET bridge on high power inverter, you won't plug it in to check if it's going to work now. You will check and measure 3-4 times and double check everything before power on.

Little OT:

Our Inverter/Converters got several protection mechanism, like overtemp, overcurrent, short circuit, etc.
But also FHCC (fault high collector current), this means the current flowing through the rails for the IGBTs will be monitoring - If the current is going rapidly high after startup (IGBTs are shorted), the unit will switch off in milliseconds...
If this error comes up, you can use a multimeter with beeping.. ;)
After replacing the defective IGBT (or IGBT Pack), I do it like this:
Powering on the auxiliary voltage, so pulses will be send to the IGBT and then increasing the railvoltage ( external supplied) slowly, watching the input current and outputsignals (by scope).
Best way to test is to test in the enviroment.
Apart from this, there are no or few testers on the market, which could test IGBTs or even packs.

http://www.ib-billmann.de/skiitest_e.php

One of very few....
So I´m thinking about to design a tester for it, for the case you couldn´t test the IGBTs in their enviroment..

OT ends
« Last Edit: December 18, 2020, 10:19:35 pm by Martin72 »
 
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Offline bayati

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #95 on: December 19, 2020, 09:38:20 pm »
I usually work with high voltage/current FETs. A 2200w power supply like "p5 miner power supply" has about 6 mosfets in the primary side and 12 in the secondary. You have to use diode test + experience.
 

Online Martin72

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #96 on: December 19, 2020, 10:15:03 pm »
Diode testing on mos-fet could only find clearly shorted ones.
You can´t find open ones (G-S or D-S), you can´t find ones with decreased breakdown-voltage ( also a chinese all in one tester, which would be unlikely better then simply diode testing, will fool you in this case, "saying" the DUT is ok*...), you can´t find ones with reduced switching function.
You can´t find anything else except short circuit.
That´s a little bit too less for me.
Me, I would test a power fet at least with the circutry mentioned in it´s datasheet, then further testing what the maximum ratings concerns.

*)We got a bunch of BUZ84 FETs for switching supplies we build.
This supply got a wide input range from 250Vdc to 450Vdc.
While testing them, nearly every of the new assembled supplies "dies" at a voltage of appx. 200...300Vdc.
Even when the defective fets were replaced from new ones.
So we test the rest of the bunch and aha, instead having a breakdown voltage of 800Vdc, nearly all tested BUZ84 breaking down at a voltage of 200....300Vdc.
From this moment on, I don´t trust any lowcurrent/lowvoltage testdevice anymore.

Online xavier60

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #97 on: December 19, 2020, 10:26:51 pm »
Diode testing on mos-fet could only find clearly shorted ones.
You can´t find open ones (G-S or D-S), you can´t find ones with decreased breakdown-voltage ( also a chinese all in one tester, which would be unlikely better then simply diode testing, will fool you in this case, "saying" the DUT is ok*...), you can´t find ones with reduced switching function.
You can´t find anything else except short circuit.
That´s a little bit too less for me.
Me, I would test a power fet at least with the circutry mentioned in it´s datasheet, then further testing what the maximum ratings concerns.

*)We got a bunch of BUZ84 FETs for switching supplies we build.
This supply got a wide input range from 250Vdc to 450Vdc.
While testing them, nearly every of the new assembled supplies "dies" at a voltage of appx. 200...300Vdc.
Even when the defective fets were replaced from new ones.
So we test the rest of the bunch and aha, instead having a breakdown voltage of 800Vdc, nearly all tested BUZ84 breaking down at a voltage of 200....300Vdc.
From this moment on, I don´t trust any lowcurrent/lowvoltage testdevice anymore.
In that case, you are checking for possible fakes rather than for parts damaged while in service.
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Online Martin72

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #98 on: December 19, 2020, 10:39:56 pm »
No.
The BUZ 84 thing was a fake, for sure - But trust me, a FET could be damaged in several ways, not only getting shorted.
Bipolar transistors you could easy check with diode test - And find out defective ones not only shorted.
Testing FETs with it, it´s only 1 or 0.

Offline bayati

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Re: Fluke 87V or the 179 vote on Twitter.
« Reply #99 on: December 20, 2020, 07:35:57 pm »
Not practical if you repair a dozen power supplies a day. Diode test is not just about shorted FETs, you can see the drop voltage and also you can open the gate and based on your experience decide if it's ok or broken. In the past year we have repaired 2254 miners in our shop based on my CRM. At least half of them had power problems. Of course in our after repair test we find new broken parts but that's how you can quickly repair more than 10 power supplies a day. You don't have time to check them with a high voltage test circuit...
 


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