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EEVblog => EEVblog Specific => Topic started by: EEVblog on June 28, 2016, 11:13:47 pm

Title: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: EEVblog on June 28, 2016, 11:13:47 pm
Inside the Keysight U1461A Insulation Resistance Multimeter

https://www.youtube.com/watch?v=wpEXm8bFlX0 (https://www.youtube.com/watch?v=wpEXm8bFlX0)
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Muttley Snickers on June 28, 2016, 11:47:49 pm
Once again a great video on a very nice product.   :-+

The blue on the terminal could perhaps be a new elaborate form of tamper detection, who the hell would have access to a blue marker pen or sharpie anyhow ?, I'd be screwed with plenty of Loctite about the place but not a blue marker anywhere to be seen.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Cliff Matthews on June 28, 2016, 11:59:28 pm
Love that soldering by the HV transfo, but what happened to C130 and C131? For a new product, I guess they didn't need the extra multiplier stage. Wah wah wah... Anyway, on the absence of a 10amp internal shunt, with all those adapters why couldn't they have rigged something external for current?
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Someone on June 29, 2016, 01:01:11 am
Shutter speed, not the frame rate was being varied to observe the scanning of the display. It can be done with frame rate too but requires fine increments.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: iloveelectronics on June 29, 2016, 03:44:24 am
In the video you mention only Fluke has a similar product but it's not exactly correct. Brymen has a new BM870 series which seems fairly comparable too, at much more affordable prices.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Muttley Snickers on June 29, 2016, 08:12:44 am
I just noticed that the remote switch probe is slightly different on this meter when compared to the similar probe on the U1280 series, The U1461A uses the U5403A lead and the U1282A uses the U5404A as linked below, looks like you could use the U5404A on the U1461A but not the other way around with the jointed input jack, thought it was worth mentioning, don't get your wires crossed.   ::)

U5403A Switch probe for the U1461A.
http://www.keysight.com/en/pd-2422444-pn-U5403A/remote-test-probe (http://www.keysight.com/en/pd-2422444-pn-U5403A/remote-test-probe)

U5404A Switch probe for the U1282A.
http://www.keysight.com/en/pd-2615346-pn-U5404A/remote-switch-probe (http://www.keysight.com/en/pd-2615346-pn-U5404A/remote-switch-probe)
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: bktemp on June 29, 2016, 08:42:18 am
What's the purpose of the two villard cascades?
I doubt they generate anything near 1000V, because there is almost no clearance around the traces.
The spacing around the transformer is much larger, so my guess would be it generates the 1kV directly using 2 windings in series with each having its own rectifier (C153, C154, D38, D39) with R135 being part of the voltage divider for the voltage regulation.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Fungus on June 29, 2016, 08:58:50 am
I doubt they generate anything near 1000V, because there is almost no clearance around the traces.

 :-//

That doesn't matter. It's not going to arc so long as there's an easier path to go down.

Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: bktemp on June 29, 2016, 09:11:09 am
I doubt they generate anything near 1000V, because there is almost no clearance around the traces.

 :-//

That doesn't matter. It's not going to arc so long as there's an easier path to go down.
If it arcs over, the arc will be the easiest path to ground. And if you have an easy path to ground somewhere else, it will load the supply and you don't have 1kV anymore.
So no, your argument is totally wrong.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Fungus on June 29, 2016, 09:18:57 am
So no, your argument is totally wrong.

Not as wrong as this: "It's not arcing so therefore it can't be 1000V"

You really think they'd release a $900 meter that can't measure voltage?
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: NANDBlog on June 29, 2016, 12:54:53 pm
The reason they dont build in the Bluetooth module: It needs to be FCC (and TÜV and who knows what else) certified, and that takes time, money... Doing that for every meter is a lot of trouble. I would not want to respin a multimeter because some RF stuff refuses to behave.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Monkeh on June 29, 2016, 01:29:41 pm
The reason they dont build in the Bluetooth module: It needs to be FCC (and TÜV and who knows what else) certified, and that takes time, money... Doing that for every meter is a lot of trouble. I would not want to respin a multimeter because some RF stuff refuses to behave.

The same reason the wifi and bluetooth in laptops is (almost) always on a card.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: bitwelder on June 29, 2016, 06:01:43 pm
Curious, the transformer placement seems to be a teeny tiny bit skewed from the main PCB axis.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: AF6LJ on June 29, 2016, 08:17:33 pm
That was a good teardown....
Nicely built.....
Thank You again for the good videos Dave.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: TheAmmoniacal on June 29, 2016, 08:22:14 pm
In the video you mention only Fluke has a similar product but it's not exactly correct. Brymen has a new BM870 series which seems fairly comparable too, at much more affordable prices.

Yep, Dave should get his hands on this for comparison.

(http://www.brymen.com.tw/product-html/cata870/870-1-950-3.JPG)
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Hydrawerk on June 29, 2016, 11:47:03 pm
What is the point of an OLED display? It must consume the AA batteries pretty quickly.
And where is the high voltage line that goes from transformer to output jacks?
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: steverino on June 30, 2016, 01:09:52 am
In the video you mention only Fluke has a similar product but it's not exactly correct. Brymen has a new BM870 series which seems fairly comparable too, at much more affordable prices.

Yep, Dave should get his hands on this for comparison.

(http://www.brymen.com.tw/product-html/cata870/870-1-950-3.JPG)
I'd like to see a brymen review also.  There was a US located member on the forum trying to source without luck.  Anybody know where to purchase one for US market?
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Fungus on June 30, 2016, 10:00:08 am
What is the point of an OLED display?

People buy shiny things. Simple as that.

I've even seen EEVBLOG members go gaga over those - people who ought to know better.

It must consume the AA batteries pretty quickly.

Yep, and it has no DC input jack so you can't plug it in when it's on your workbench. You need to constantly stop work to change/charge the batteries. :palm:

The engineers must have facepalmed when management told them to make a meter that can only be used in dim lighting and you need to charge it every other every day (via the input posts!).

Marketing knew best though: There's a whole sector of drooling idiots who only see "color display!!!!"

The only thing missing is an Apple logo.

PS: The 'drooling idiots' aren't necessarily the meter owners. If I was a consultant I'd buy a huge OLED meter just so could pull it out in front of clients to show how amazing I am.

The other guy has a black and white meter, mine is color. Who you gonna hire...?

(And pray the boss leaves before the battery runs out...)
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: EEVblog on June 30, 2016, 11:49:56 am
In the video you mention only Fluke has a similar product but it's not exactly correct. Brymen has a new BM870 series which seems fairly comparable too, at much more affordable prices.
Yep, Dave should get his hands on this for comparison.
(http://www.brymen.com.tw/product-html/cata870/870-1-950-3.JPG)

Hmm, I didn't know about that model.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: EEVblog on June 30, 2016, 11:54:47 am
The reason they dont build in the Bluetooth module: It needs to be FCC (and TÜV and who knows what else) certified, and that takes time, money... Doing that for every meter is a lot of trouble. I would not want to respin a multimeter because some RF stuff refuses to behave.

You simply use a pre-certified module and solder to the board. I'm doing that for my custom meter design.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Hydrawerk on June 30, 2016, 06:40:08 pm
I have no problem with OLED displays on a bench meter, that is not powered from batteries.
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: f4eru on June 30, 2016, 08:30:22 pm
Hello,
The blue glue on the ground post screw is a safety feature : if the screw comes loose, and the ground post is lost, the whole meter "potentially" goes to 1000V, and it can arc over to your fingers at many places (in worst case). So that ground connection is safety relevant.

The two cascades are probably for different voltages : the two with the small components and 4 stages are probably for 50V, the one with big component and one stage is for higher voltages.

The presence of the 6uA range is easy to explain : that is what is used to measure the very high resistances !
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: Muttley Snickers on July 01, 2016, 03:15:46 am
Peter Oakes also did a couple of video reviews on this meter and the common terminal was not blued on his one as shown below, if it was used to lock the thread then I would expect to see remnants of it on the thread itself but this is sometimes not the case in all applications.

Peter Oakes U1461A general review.
https://www.youtube.com/watch?v=SqxLOFWnr_I (https://www.youtube.com/watch?v=SqxLOFWnr_I)

Peter Oakes U1461A chilling review.
https://www.youtube.com/watch?v=tPt1qaie3Xo (https://www.youtube.com/watch?v=tPt1qaie3Xo)
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: peteb2 on July 02, 2016, 09:34:45 am
Yep... great meter and yeah i own one but what i really like is the external software Keysight make available for it, especially the handy-dandy database around insulation testing when you are required to track a whole bunch of different equipment...
Title: Re: EEVblog #894 - Keysight U1461A Insulation Resistance Multimeter Teardown
Post by: peteb2 on July 02, 2016, 03:30:41 pm
... and here's what is probably Keysight's own produced videos on YouTube explaining this software but i am sorry, the young lass who explains things obviously has English as a second language. I've watched it 10 times... i'm still confused.

https://www.youtube.com/watch?v=7ohDYKEs2bU (https://www.youtube.com/watch?v=7ohDYKEs2bU)

https://www.youtube.com/watch?v=UAGq_LTfmb4 (https://www.youtube.com/watch?v=UAGq_LTfmb4)