Author Topic: EEVblog #832 - Keysight U1282A Multimeter Teardown  (Read 26408 times)

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Online VK5RC

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #50 on: December 23, 2015, 09:08:48 am »
While a little off topic (teardown) I thought the leads were not up to KS usual standard and are a bit stiff, not their usual pliable leads.
It is a BIG and HEAVY DMM.
Is it just me or is the dual display of DC V and AC V not highly sort after, yet it is about the third option in the dual display function after dBmV etc ???
Whoah! Watch where that landed we might need it later.
 

Offline Ricardo

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #51 on: December 25, 2015, 02:55:55 pm »
Dave finds 2 MAX4611 circuits on this board and wonders why 2 Voltage Detectors are needed.  Voltage Detectors = MAX 6411  ;D
MAX4611 = CMOS Analog Switches
 

Offline Dubbie

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EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #52 on: December 25, 2015, 08:03:46 pm »
Does anyone know how you wake it up after it has gone to sleep? I wish wish wish that you could just push any button on meters to get them to turn back on instead of cranking the stupid dial round to off then back again to where you were. Super infuriating for bench use. My Bryman makes you do that whereas my fluke 289 has a nice on off button but a huge long boot up delay. If this meter would wake up instantly on a button press I will buy one.


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Offline K6TR

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #53 on: December 26, 2015, 04:07:04 am »
I'm looking forward to the formal Product Review of this meter Dave. I would also like to see a review of the 1461 Insulation Tester/Multimeter. I have my heart set on Keysight coming out with a an OLED Version of the 1280 Series as I really like the OLED they use on the 1253B, don't have use for the Insulation Tester and can't justify laying out the money Keysight is asking for the 1461. They have done some things to address the short battery life in the 1253 and while a long ways from ideal 50 Hours use in the 1461 with Alkaline Batteries is a substantial improvement over the 1253B.

Enjoy your time off Dave.
« Last Edit: December 26, 2015, 04:09:20 am by K6TR »
 

Offline ali_asadzadeh

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #54 on: December 26, 2015, 01:22:25 pm »
Dave are they worth their price? what are the alternatives?
I'm a Digital Expert from 8-bits to 64-bits
 

Online VK5RC

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #55 on: December 27, 2015, 06:28:13 am »
@Dubbie, after the u1282 goes to sleep, you can wake it up by hitting the centre blue button (it worked for me twice this afternoon), it goes back to the same function as set on the switch.
For me the biggest negative issues are 1. its size, 2. the leads are a bit non-pliable.
Positives; seriously accurate and switches on quickly, I tend to switch off between readings. :blah:
Whoah! Watch where that landed we might need it later.
 

Offline Dubbie

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #56 on: December 27, 2015, 10:36:54 pm »
Well I feel like a dumbass. Just read the Brymen manual again and discovered it does turn on with a button press. Maybe I didn't press them long enough for the debounce. The new Agilent looks nice as well. I need one more meter. Shame it is so huge.


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Offline zaoka

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #57 on: December 28, 2015, 03:03:56 am »
Did they fix Capacity issues they had with U1272A? Smoothing mode works now?

Also display contrast looks better than U1272A...

I like it a lot except font for digits, somehow space between digits is dense...
 

Online EEVblog

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #58 on: December 28, 2015, 09:47:11 am »
Dave finds 2 MAX4611 circuits on this board and wonders why 2 Voltage Detectors are needed.  Voltage Detectors = MAX 6411  ;D
MAX4611 = CMOS Analog Switches

 :palm:  :-[
 

Online EEVblog

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #59 on: December 28, 2015, 09:49:05 am »
Dave are they worth their price? what are the alternatives?

Yes if it meets your requirements.
Fluke 28 II is a direct competitor in the rugged field category.
For a general bench meter I'd rather have the U1272A
 

Offline jpb

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #60 on: December 29, 2015, 06:45:59 pm »
I don't know if I've missed it, but from the data sheet and user guide it doesn't seem to have a real-time-clock unlike other logging meters (eg the Fluke 287/289 and the Gossen meters)? This probably helps battery usage but means you have to have it tethered to a pc in some way if you want to log with time stamps? You can set time intervals for logging but this is not quite the same thing. It also has a relatively small logging memory.

I'm currently looking for a high-end meter and the U1282A has good specs and seems robustly built with very good battery life but for some reason I feel that it seems to have been designed to tick a lot of spec boxes rather than as a single product. It is also more expensive than the Fluke 287 in the UK and say the Gossen Ultra (both of which though have major drawbacks like very low battery life and no analogue display on the Gossen).

Dave - have you done real world tests on the various claimed battery lives? I know it is a feature that you are hot on. I just wonder when you have the Fluke 289 only getting 100 hours out of 6 AA batteries (I think) and the U1282A claiming 800 hours (dc V) from 4. The Gossen meters rate themselves at 200 hours but from just 2 AAs.
« Last Edit: December 29, 2015, 06:48:03 pm by jpb »
 

Offline Muttley Snickers

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #61 on: December 29, 2015, 10:27:24 pm »
I found a couple of teasers which will have to do until Dave gets back from exhaustive testing in relation to lateral resistive integrity of sand castles..... :)



 

Offline joeqsmith

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #62 on: December 31, 2015, 12:11:59 pm »
Anyone knows what is the reason for heatshrinking those resistors and PTCs?

joeqsmith managed to turn a few PTCs into green dust over in the "here kitty" thread.  I'm guessing the heatshrink is to stop them messing up the inside of the meter when you zap them too hard.

Although if you're regularly exploding your PTCs you might want to consider a whole new meter just in case, and wrapping them in heatshrink might hide any damage  :-//

On a side note: How fast do PTCs react? Surely they have to physically heat up and that takes a few milliseconds at least. Joe's PTC-destroying pulses are only a few microseconds long.

And MOVs, how fast are they? Presumably a lot faster than PTCs.

MOVs will switch much faster than a GDT.  GDTs are in the microsecond range.   They are good for high energy, long long duration but because they are so slow, I would have something to help them out.  You could get away using a smaller MOV as it would only need to handle the energy until the GDT fires.  If they use some sort of diode clamp, there must be another layer of R after that last GTD.   Would be interesting to sketch it out and see if at least on paper that it could survive something with a fast edge.   

I have seen a few HV resistors fail in the meters and a few PTCs.  You are right, the PTCs when coated will come apart even with very low energy levels.  I have had a few where there is nothing left but the leads when I put a little more in them.   It makes sense that they heat shrink them to prevent the fragments from getting into the meter but I am not sure if that really is the reason for it.  :-//

The attached pictures were taken from Dave's original video showing the GDT and input protection.   The GDT is marked 2000 1411.  I was unable to determine what that exact device is.   It would have been helpful to know the value of the input resistor and PTC resistance/trip current as well.   This video shows an input circuit based on a production handheld meter.   I provided all of the manufactures and part numbers.  I used the same MOVs used in the meter.   The circuit was subjected to my standard  5KV pulse and I show what the waveform looks like across the MOVs.  The MOVs are then swapped out for a GTD and once again the test pulse is injected.   



Dave had made another video on multimeter input protection  which may be found here:


Using a Fluke as his model, he does a very good job explaining the basics.   

By no means can we draw any conclusion about the U1282A's robustness based upon my video but it at least it demonstrates what I described and explains what I have seen as far as failures.   

How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #63 on: January 31, 2016, 06:26:32 pm »
I did pick up a Keysight meter with GDTs to try out.   

Part 2 Running the test


Part 1 Basic overview of the meter

How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline saturation

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Re: EEVblog #832 - Keysight U1282A Multimeter Teardown
« Reply #64 on: November 20, 2016, 03:49:12 pm »
I have opted to get one 1282a upgrade and will keep my other 1272a so this thread piqued my interest.  While I like the toughness of the casing the GDT design in Keysight DMM input protection has always concerned me, not that it won't protect, but it will protect but lead to meter destruction.  Also the size is starting to get unwieldy for a field device; small, light and toughness are bigger concerns given airline costs and luggage limits.

As expected, when Joe did the test on a cheaper Keysight DMM with GDT protection, it died.  This is similar protection used on many of the Keysight DMMs.  Only a full test per model would say for sure.

The standard MOV design allows the meter to survive and take a large spike, as Joe Smith easily demonstrates.  That said, the test 87V failed under Joe's hands, but the other well designed MOV based protection have survived, e.g. other model Flukes, Brymen etc., also an 87V is shown on Fluke's marketing videos taking hits to 12kV, but that's on AC volt mode.

Starts at 17:00




« Last Edit: November 20, 2016, 03:56:26 pm by saturation »
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