Author Topic: EEVblog #933 - Keysight U1272A EMC Issue  (Read 210482 times)

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Offline lowimpedance

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #575 on: November 29, 2017, 02:57:22 am »
Yes, you can just CAL the ohms without doing any other function, (indeed any of the other functions can also be done singularly to),  but be wary that trying to do the short and open tests of the 'ohms CAL' alone will not do it seems.
I just tried that with the replacement meter, ie doing the 'Short and then Open' part only and then exiting the adjustments without doing the complete ohms CAL.
 And when the meter restarted with no leads connected the display showed around 5M \$\Omega\$ on the display  :-//. I noted that behavior with the 'modded' meter but thought I did something wrong and dismissed it as I went on and did the full ohms CAL.

 So my recommendation would be do the mods and check as best you can (comparison with other Meters etc) that its still within spec. and don't try the CAL unless you have the required stable known resistors to hand. IIRC as I stated earlier only the ohms and possibly the DC current zero's shifted a bit and adjustment was not really needed.
Remember the NULL function. I have noted too that the ohms zero will drift around a few counts anyway (temp. related!).
Also I did not bother with any matching of the resistors.

Having access to the required calibrator has made it easier for me of course to do the CAL. but I would have been happy leaving it as is. Particularly if cross referencing with other meters gave similar results within their respective specs.

An interesting side note, when I checked the number of CAL cycles the new replacement 1272a that Keysight sent me it had already done 15  :o....... go figure.
« Last Edit: November 29, 2017, 02:59:52 am by lowimpedance »
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 
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Offline rauldm

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #576 on: November 06, 2021, 05:31:21 am »
You need back defective u1272a to Keysight for receive new meter?
 

Offline HighVoltage

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #577 on: November 06, 2021, 08:34:15 am »
You need to contact Keysight and they will tell you what to do.
In the past, when I had the problem with my meter, they requested a picture of the serial number and then sent a new meter free of charge and I could keep the old one.
There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline rauldm

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #578 on: December 20, 2021, 12:41:51 am »
I bought a Agilent u1272A, this meter is new, it was made in 2012, but it comes with all accessories and its original box like new, it works very good, I update to latest firmware and can come with DC Low pass filter, it doesn't show problem with EMC, but I disable Low pass filter it shows false lectures of dc current, really is not a problem for me, BUT in ohm mode always shows 167-170 MOhm value even without probes, someone with this issue?
Regards.
 

Offline rsjsouza

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #579 on: December 20, 2021, 01:46:40 am »
That value of resistance may well be a problem of storage. One possibility (most probable, IMO) is that it might have been stored in an area with high humidity, which caused contamination on the board around ingress points (the input jacks are the higher probability). A cleanup with isopropyl or other mild cleaner can be of help.

Another possibility is out of tolerance/calibration or even damage caused by temperature (or physical) stress that might have damaged or changed a component's value on the board. At this point I would consider opening the meter and seeing how it is inside, unless Keysight grants you their warranty (I got a full warranty on my NOS U1273A from them after showing the receipt from the store).
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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline rauldm

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #580 on: December 20, 2021, 03:19:07 am »
I opened the meter, I found white dust, I cleaned with hyssop, also I cleaned the dial selector. Is same, I found, if I put test leads and they move without touch nothing OL is show, if I remove test leads always is oscillating in 160 MOhms
 

Offline pt1elec_dev

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #581 on: September 21, 2022, 12:48:56 pm »
Sorry to bring this old topic up again.
I have been using this meter for awhile not exactly from when but quite old. Anyway, I tested mine as Dave did in his video and confirmed mine is also affected.
To get any available service, I reached local Keysight office but they refused for any service and said I have to buy a new one for a full price.
Yes, the warranty has expired but... even for this issue?

Any experience with a old, warranty expired equipment with Keysight?
 

Offline wraper

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #582 on: September 21, 2022, 12:58:36 pm »
Sorry to bring this old topic up again.
I have been using this meter for awhile not exactly from when but quite old. Anyway, I tested mine as Dave did in his video and confirmed mine is also affected.
To get any available service, I reached local Keysight office but they refused for any service and said I have to buy a new one for a full price.
Yes, the warranty has expired but... even for this issue?

Any experience with a old, warranty expired equipment with Keysight?
Multimeter replacement program was separate from warranty but it was time limited. I received U1282A as replacement and kept U1272A too.
 

Offline pt1elec_dev

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #583 on: September 21, 2022, 01:05:23 pm »
but it was time limited.
Okay... sad news. Thanks for sharing.
 


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