Fluke 87V (2021) teardown

[SerjP]

Good day, EEV bloggers!

New member here. I'm a former EE but am currently writing "boring business software" as someone said well on this forum. So, already being an amateur, I felt that I needed a good new reliable tool.

I read all these battles here on the forum, comparing one in a yellow holster to another in a red one. Yelow or red? Hmm... good question. And I'm already have one DMM in a red which is Uni-T UT71E. Which sometimes has glitches (smth. with selector contacts?), too loud beeper, fluctuating digits, terrible continuity mode, etc. So I decided to buy a more reliable one.
The things I considered for new DMM is:

• long-term stability (as I believe I can't afford going to certification labs every xx years)
• reputation/brand (well I never had anything from the top echelon before)
• and perfect internal design (look at that 87v board and the number of elements - the simplicity is a key; "beautiful" as Dave likes to say)

So finally I selected to buy the yellow one. It will be my only top grade DMM on the bench.
I think the number of digits is not that important to me and can be distracting. While less crowded dial is a plus.

The phrase on the Dave's blog I love the most is - "don't turn it on, take it apart!!!". Cool! This is exactly what I planned to do.
Of course I checked if it works correctly before doing that. I have also compared and recorded the readings in all ranges with the Uni-T (I can share results). So that after assembly I can make sure that the readings are the same and that teardown does not affected the accuracy.
Some teardown justification: I wanted to see the overall build quality, to check if shield is not bended (I've seen pictures on this forum) and to check the fuses brand.

So, here are some photos of the internals for those who would like to check the revision number and to compare with previous versions.
Bought it from the well-known German online store W****.
MFG date: Sep2020

[SerjP]

Printed circuit assembly

[SerjP]

Mileage for knob is less than 100 cycles. And we already can see some tracks on the PCB.
Also there is no grease on detent spring (see 3rd photo; those scratches on the case is not a grease, it's just a scratches).

[Wytnucls]

First one I see with Littelfuse fuses instead of Bussmann.

[SerjP]

Some comments and questions from me:

• Leads are TL175
  looks a little better than TL75
• Shield is not bended
  we are good here
• O-ring on the input terminal assembly is missing
  did you noticed that from photos? This was unexpected. At least for Fluke
  I've already contacted seller for that. They were as surprised as I was. And kindly provided solutions to resolve this issue. So I'm waiting for a new O-ring from them.
• Fuses brand
  I've always worked with fuses that cost ~10 cents. So can't complain here. BTW Bussmann costs $50 on Digikey while Littelfuse is $25 (crazy prices anyway, lol). This is where Fluke gets the cost down. Is Littelfuse as good as Buss?
• Lack of grease on the detent spring
  Do we need any grease here at all? I've added some consistent grease of unknown quality. I suppose it is better than nothing. Is it ok? I'm not an expert on materials, so I have no idea if a grease of unknown quality/brand can damage/disintegrate plastic over time.

PS: the unit cost me ~400€ what is $480 (sales). I checked tme.eu and the price is $685 (VAT incl.). Also I found that in some USA shops the unit is also on sales/discount for $400. So it looks like a worldwide discounts, not only here in Europe. I hope discounts have nothing to do with those quality aspects noticed above.

[Per Hansson]

What is the 9v battery lead doing underneath the 11A fuse for the amps mode?
If they thought that was a good routing idea why even bother with a fuse with a 11kA interrupt rating or whatever it is? 

[Arhigos]

What is the 9v battery lead doing underneath the 11A fuse for the amps mode?
If they thought that was a good routing idea why even bother with a fuse with a 11kA interrupt rating or whatever it is? 

what's wrong with battery lead?

[J-R]

My 87V from late 2018 has the battery wires in the same setup.  Contemplating the potential current paths, I am not seeing a cause for concern, though.

[Arhigos]

My 87V from late 2018 has the battery wires in the same setup.  Contemplating the potential current paths, I am not seeing a cause for concern, though.

All of them had same design for battery cable, beginning from original 87 in early 90-s.

I never heard about any problem with that part

[EEVblog]

Thanks for sharing.
How old is the 87 line now?
Introduced in the late 80's IIRC.

[Monkeh]

What is the 9v battery lead doing underneath the 11A fuse for the amps mode?
If they thought that was a good routing idea why even bother with a fuse with a 11kA interrupt rating or whatever it is? 

Because the battery leads are sleeved with silicone-impregnated fibreglass which will be rated to at least 1kV?

[Wytnucls]

Fuses brand
I've always worked with fuses that cost ~10 cents. So can't complain here. BTW Bussmann costs $50 on Digikey while Littelfuse is $25 (crazy prices anyway, lol). This is where Fluke gets the cost down. Is Littelfuse as good as Buss?

Littelfuse fuses are rated the same, but are somewhat cheaper.
Unless things have changed dramatically recently, all new 87 V meters come with Bussmann fuses.
Are you sure this meter hasn't been tampered with, before you bought it?
A missing O-ring and suspicious fuses make me wonder.

Contact Fluke Germany if you want to find out:

Fluke Deutschland GmbH
Heinrich-Pesch-Straße 9-11
D-50739 Köln
Tel.: +49 0(69)2222 20210
Fax: +49 0(69) 2222 20224
Email: service.de@fluke.com

[Fungus]

Thanks for sharing.
How old is the 87 line now?
Introduced in the late 80's IIRC.

There's been V revisions of it though, some of them were quite big changes.

The real question is how old is the 87V now and why did they stop innovating it?

[Wytnucls]

What for? It does the job, is well respected in the industry and has a long history. Why would you want to jeopardize all of that for some elusive extra sales?

[Fungus]

What for? It does the job, is well respected in the industry and has a long history. Why would you want to jeopardize all of that for some elusive extra sales?

a) It was innovated before. The meter got better and nothing bad happend.

b) Can you really think of nothing that could improve it?

eg. 9999 counts so you have the same number of digits on screen when you measure 5V and when you measure 7V?

[Wytnucls]

Not much changed over the years (1988 Fluke 87, 1998 Fluke 87 III), if you discount the 87/89 IV (1999) which was completely different:

IP30
VFD (low pass filter)
Temp
Higher diode test voltage
Extra capacitance range
Slightly better accuracy with a 6,000 count instead of 4,000

That's it!

[Fungus]

Not much changed over the years (87, 87 III), if you discount the 87 IV which was completely different:

IP30
VFD
Temp
Higher diode test voltage
Extra capacitance range
Slightly better accuracy with a 6,000 count instead of 4,000

That's it!

Why did they stop? Dave's review of the 97V was in 2009!

[Wytnucls]

They have the 289, with all the bells and whistles already, since 2007. Call it Fluke 87 VI and be done with it! 
Industry doesn't like big changes. People need to be retrained, manuals to be rewritten, insurance policies modified, etc...
Some companies still use Windows 3.1

[Per Hansson]

What is the 9v battery lead doing underneath the 11A fuse for the amps mode?
If they thought that was a good routing idea why even bother with a fuse with a 11kA interrupt rating or whatever it is? 

Because the battery leads are sleeved with silicone-impregnated fibreglass which will be rated to at least 1kV?

Ok, I just assumed it would be bad design practice, as for example you often have wide PCB cutouts for preventing arc-over.
But here we have a cable literally clamped in the fuse holder (refer to picture: "2.1 DSC03156_.jpg")
I based this off my experience of fuse holders with those stupid series lamps that light up to tell you the fuse failed:
When the manufacturer places them in high energy circuits the whole fuse holder catches fire and melts into a mess.
But granted the wires are not covered in sleeving so I guess Fluke knows what they are doing, it just rubbed me the wrong way seeing that...

[Monkeh]

What is the 9v battery lead doing underneath the 11A fuse for the amps mode?
If they thought that was a good routing idea why even bother with a fuse with a 11kA interrupt rating or whatever it is? 

Because the battery leads are sleeved with silicone-impregnated fibreglass which will be rated to at least 1kV?

Ok, I just assumed it would be bad design practice, as for example you often have wide PCB cutouts for preventing arc-over.
But here we have a cable literally clamped in the fuse holder (refer to picture: "2.1 DSC03156_.jpg")
I based this off my experience of fuse holders with those stupid series lamps that light up to tell you the fuse failed:
When the manufacturer places them in high energy circuits the whole fuse holder catches fire and melts into a mess.
But granted the wires are not covered in sleeving so I guess Fluke knows what they are doing, it just rubbed me the wrong way seeing that...

Well, I'm no subject expert, but I'm not particularly concerned about an insulated assembly rated to >1kV in the presence of <1kV.

[SerjP]

Thanks for sharing.

My pleasure Dave.
I have more hi-res photos, can share if anyone is interested. Did not uploaded them due to forum limitations.

Littelfuse fuses are rated the same, but are somewhat cheaper.
Unless things have changed dramatically recently, all new 87 V meters come with Bussmann fuses.
Are you sure this meter hasn't been tampered with, before you bought it?
A missing O-ring and suspicious fuses make me wonder.

Contact Fluke Germany if you want to find out:

Fluke Deutschland GmbH

Thank you @Wytnucls. Dropped them a message.
I suppose meter hasn't tampered. When I removed the screws I noticed the force it takes to unscrew them. When the item is new and was never disassembled it usually require a good amount of torque to remove the screws from ABS plastic. So based on my previous experience I'm pretty sure unit was not unscrewed before. Accordingly for the second, third times it usually so much easier to remove the screws. But yearh.. good point anyway, thanks.

Ok, I just assumed it would be bad design practice, as for example you often have wide PCB cutouts for preventing arc-over.
But here we have a cable literally clamped in the fuse holder (refer to picture: "2.1 DSC03156_.jpg")
I based this off my experience of fuse holders with those stupid series lamps that light up to tell you the fuse failed:
When the manufacturer places them in high energy circuits the whole fuse holder catches fire and melts into a mess.
But granted the wires are not covered in sleeving so I guess Fluke knows what they are doing, it just rubbed me the wrong way seeing that...

I agree those sleeve underneath the fuse is that's smth. what you immediately pay attention to. Not the best design decision. Though while fuse is not blown the potential here on fuse holder clamps is about a couple of mV to the ground due to fuse extra low resistance. So no ways arc can arise here. The only way for arc to arise is to measure high voltage circuits (lets say more than 1kV) and high energy at the same time in order to blown the fuse (lets say more than 30A). Then yes that dangerous voltage would potentially trigger an arc to the battery leads. What voltage we need here to go through sleeve and through battery leads insulation? I guess more than 10kV. I've seen some test on youtube for that particular case (see below). BTW working with so high voltage/energy is out of scope for this meter, its even not a cat. IV I guess.

[rsjsouza]

Are you sure this meter hasn't been tampered with, before you bought it?
A missing O-ring and suspicious fuses make me wonder.

Well, if W****** is a Fluke authorized distributor and the meter was purchased *new*, that possibility would be a very troublesome scenario.

[Per Hansson]

Ok, I just assumed it would be bad design practice, as for example you often have wide PCB cutouts for preventing arc-over.
But here we have a cable literally clamped in the fuse holder (refer to picture: "2.1 DSC03156_.jpg")
I based this off my experience of fuse holders with those stupid series lamps that light up to tell you the fuse failed:
When the manufacturer places them in high energy circuits the whole fuse holder catches fire and melts into a mess.
But granted the wires are not covered in sleeving so I guess Fluke knows what they are doing, it just rubbed me the wrong way seeing that...

I agree those sleeve underneath the fuse is that's smth. what you immediately pay attention to. Not the best design decision. Though while fuse is not blown the potential here on fuse holder clamps is about a couple of mV to the ground due to fuse extra low resistance. So no ways arc can arise here. The only way for arc to arise is to measure high voltage circuits (lets say more than 1kV) and high energy at the same time in order to blown the fuse (lets say more than 30A). Then yes that dangerous voltage would potentially trigger an arc to the battery leads. What voltage we need here to go through sleeve and through battery leads insulation? I guess more than 10kV. I've seen some test on youtube for that particular case (see below). BTW working with so high voltage/energy is out of scope for this meter, its even not a cat. IV I guess.

Thank you very much for the linked video, it prooves well that I was wrong
And thanks for your pictures

[SerjP]

Though while fuse is not blown the potential here on fuse holder clamps is about a couple of mV to the ground due to fuse extra low resistance.

It seems I should take my words back. I just watched Dave's recent video about fuses. Couple of mV? no way  its may be even <spoiler> 5V! </spoiler>
But anyway it is too low, no chances for arc until fuse hasn't blown.

PS: Also Dave said in that video the Littlefuse is a top brand and installed in Flukes. Hmmm.. Then I probably have to stop worrying about my fuses. But... I've only saw Buss in Fluke DMMs.

Thank you very much for the linked video, it prooves well that I was wrong
And thanks for your pictures

Thank you. There is nothing wrong with your approach to check all possible scenarios when we are speaking about safety. It is better to prevent the accident by all possible means.

[tooki]

• Fuses brand
  I've always worked with fuses that cost ~10 cents. So can't complain here. BTW Bussmann costs $50 on Digikey while Littelfuse is $25 (crazy prices anyway, lol). This is where Fluke gets the cost down. Is Littelfuse as good as Buss?

I wanna say that I’ve heard before that Fluke uses both Bussmann and Littelfuse, though Bussmann is clearly the more common one. They’re both top brands (together with Siba, another large, reputable maker of proper multimeter fuses). I see nothing suspicious about this at all.

Note that the prices for those fuses (regardless of manufacturer) are always insane when bought under the fuse brand. You invariably pay FAR less for them when bought as Fluke items (which DK isn’t allowed to ship outside of USA, which is why they weren’t offered to you). At work, we recently stocked up on “Fluke” fuses from Conrad for around $6 each. (Bussmann is what arrived of course.)