U1271A/U1272A/U1273A/U1273AX models/likes/dislikes/tips

[LaurentR]

For any prospective buyer or happy/unhappy owner, here is an attempt at listing all the good and bad things about the U1271A/U1272A/U1273A/U1273AX. Feel free to add/comment.

I am very happy about my U1273A (I love the screen and the local and remote logging capabilities) but the thing has definite quirks and could be improved. It's more than 4 years old by now, so let's just hope for an eventual refresh 

Models:

• U1271A ($347): U1272A minus some features (No Zlow, no SmartOhm, no AC+DC TrueRMS, 20kHz AC BW vs 100kHz, no 30mV range, no 30Ohm or 300MOhm ranges, no auto diode test, 200 entry logging vs. 10k)
• U1272A ($378): Main model.
• U1273A ($404): Same as U1272A but with OLED screen.
• U1273AX ($451): Same as U1273A but with extended operating temperature range to -40C

Latest Firmware:

• U1271A/U1272A: 2.04 (2013-07-05)
• U1273A/U1273AX: 1.95 (2013-08-05)

Reviews:

• Dave's U1272A teardown:
• Dave's U1272A Fail (fixed in recent firmware versions):
• Agilent's U1272A Response:
• Dave's U1272A review:
• Kiriakos' U1272A review thread: https://www.eevblog.com/forum/testgear/agilent-u1272a-review-by-kiriakos-triantafilloy-greece/
• Martin's U1272A review:
• Roadtest at element14: http://www.element14.com/community/roadTestReviews/1002

Likes

• Solid. IP54 rated.
• U1273A/U1273AX OLED screen indoor. Very readable large digits. Scales down for dual display. Better GUI especially for setup. (LaurentR)
• Lots of logging options with good memory size. Good Bluetooth modules and apps/sw (LaurentR).
• Arbitrary V/A conversion factor (electr_peter).
• SmartOhm (electr_peter).
• Continuity threshold adjustable with Range button. Backlight continuity alert on U1271A/U1272A (Zbig).
• Calibration certificate with calibration results for all ranges.
• Leads are high quality silicone. 15A rated and AWG16 (higher than all Fluke leads). Two-parts for more flexibility.

Dislikes

• Continuity is scratchy. It is latching, but still scratchy while a firm contact is not made. There is a funky multi-tone option for continuity that plays a melody depending on quality of the contact. Continuity threshold can be changed with the Range button. The U1272A also has a really nice screen flashing option (backlight turns on), which actually works better than the buzzer.
• Connecting the leads to mains (or any high voltage) for enough time changes measurements on some ranges (e.g. the lowest resistance range). This is possibly due to self-heating. Recovery takes several minutes.
• Capacitance measurements seem marginal. I don't own a DMM I can trust with capacitance tests, so I am not sure how true this is.
• Zlow mode shows ~2-3VAC with shorted inputs.
• The U1273A/U1273AX OLED screen is hard to see in bright daylight. It is gorgeous indoor (and the dot-matrix gives it a better interface than that of the U1272A), but it's really bad outdoor, to the point of just not being able to see anything. See for a comparison of the 2 screens outdoor.
• The U1273A/U1273AX have reduced battery life due to the OLED display. Rated at 60hr Alkaline / 100hr Lithium vs. 300hr Alkaline for the U1272A.
• APO is fully settable but beeps right as it turns off, leaving no time to prevent it.
• Off position is not the left-most one on the rotary selector. There is a "Zlow" selection completely to the left. Minor annoyance.
• Beep on power-on. The frequency of the beep can be picked (or the beep can be turned off), but this option changes the beeps of all functions, including continuity. The most ridiculous is the U1273A that has a melody option on power-up...
• The screen seems to scratch very easily (on the U1273A at least). See this thread.
• Provided leads are good quality but the handle is in two parts, which makes them quite long.

Tips

• For faster stabilization of readings, turn off DC LPF in settings (that's a change in the latest firmware).
• After doing mains work, wait several minutes before doing precision electronics measurements (watching Ohms of shorted leads is a good indication).
• Turn off unused features in setup (dB, mA scale, melody).
• If using rechargeable batteries, set the battery type to "SEC" in setup.

Accessories:

• U1177A IR-Bluetooth adapter (10m range class 2)
• U1117A IR-Bluetooth adapter (100m range class 1)
• U1173A/B IR-USB adapter
• Free iPhone, Android and Windows apps

[retiredcaps]

Martin's review of the U1272A.

[LaurentR]

Martin's review of the U1272A.

I had watched but somehow didn't list it
Thanks!

[electr_peter]

Continuity is scratchy. It is latching, but still scratchy while a firm contact is not made. There is a funky multi-tone option for continuity that plays a melody depending on quality of the contact. I find it better than the plain continuity buzzer, but it's funky. The U1272A also has a really nice screen flashing option (backlight turns on), which actually works better than the buzzer. The U1273A has no such option.

U1272A has nice solid buzzer plus it can show full resistance range (in the mega Ohms) in continuity mode if range button is pressed.

Connecting the leads to mains (or any high voltage) for enough time changes measurements on some ranges (e.g. the lowest resistance range). This is possibly due to self-heating. Recovery takes several minutes.

At least they protect and inform you about the danger which is the most important thing. Crap DMMs only show high voltage symbol when you select high voltage AC/DC range independent of actual voltage - this is utterly useless gimmick.

Capacitance measurements seem marginal. I don't own a DMM I can trust with capacitance tests, so I am not sure how true this is.

Such type of DMMs cannot accurately measure capacitance on low ranges. If you are desperate with low value caps, try using very short leads - it helps reducing overall system capacitance.

Off position is not the left-most one on the rotary selector. There is a "Zlow" selection completely to the left. Minor annoyance.

Annoying, but not quite, other manufacturers also do this if Low Z mode is available. Actually, LowZ mode has much strong de-tent on purpose so lighter turn of knob to the left will land you in off position.
Also, both off and LowZ positions have a low impedance of ~1.7kOhm, be aware of this.

Beep on power-on. The frequency of the beep can be picked (or the beep can be turned off), but this option changes the beeps of all functions, including continuity. The most ridiculous is the U1273A that has a melody option on power-up...

U1272 beep cannot be fully turned off - beeper is not completely disconnected and you can hear faint clicks in silent room. You only have option of beeps or silence (meaning only one setting for turn on beep, button beeps, continuity beep). Separate settings would be nice.

Provided leads are good quality but the handle is in two parts, which makes it quite long. Nothing a good set of Fluke TL71 can't fix...

Get single piece construction Agilent leads if you don't like two piece design.

Nice and accurate meter overall, has arbitrary amps/volts conversion factor and smart-Ohms measurement.

[Muttley Snickers]

I have a couple of U1272A's and only use them periodicallyand out of all the meters that I use its the only one that I find that a quick refresher course is required every time that they come out, some of the hold down features are not that intuitive unless you are using them frequently.

I keep meaning to print up and laminate a small cheat sheet and stick it in behind the bail, maybe tomorrow.

Also nearly forgot, on my 189 and also on a twenty year old Dick Smith meter I have the ability to latch the continuity buzzer with a momentary contact on the probes, this is handy when working in large complex's and factories, maybe there is a trick to getting it to work on the U1272A's.

Otherwise one of my favourite bits of kit......


Muttley

[wirbelwind]

Don't forget the short battery life on the U1273A and in the LowZ shows the meter 2V  - 3V without any voltage.

[128er]

and out of all the meter's that I use it's the only one that I
find that a quick refresher course is required every time
that they come out, some of the hold down feature's are
not that intuitive unless you are using them frequently.

Even if the U1273A is my regular DMM for private work. I always have to look up some features in the manual, that I don't use very often. Or I try to remember and start poking around the knobs and get the function quite fast 

I keep meaning to print up and laminate a small cheat
sheet and stick in in behind the bail, maybe tomorrow.

Very good Idea. Would be handy.

Otherwise one of my favourite bit's of kit......

Confirm that 

Nice and accurate meter overall, has arbitrary amps/volts conversion factor

Like that too!


Things like the beep at start up, or Zlow at the most left position on the switch are not sooo annoying to me. I got used to it quite fast. But the start up melody I changed very quickly.

The crapy display cover however is shit. Nothing that should happen on a industrial grade meter.

About the Zlow range. Yes, my meter also shows usually 3,3 VAC. Even if the voltage that is present is for example 2.0 VAC.

And the Datasheet says:
-AC V and AC ?A/mA/A specifications are AC coupled, true RMS and are valid from 5% of range to 100% of range.

- After ZLOW voltage measurements, wait at least 20 minutes for thermal impact to cool before proceeding with any other measurement.

And the specification for Zlow range is 2% of range + 40 counts of LSD at 45 to 65 Hz.

Zlow is definitely not made for rocket science.

[Zbig]

• Continuity is scratchy. It is latching, but still scratchy while a firm contact is not made. There is a funky multi-tone option for continuity that plays a melody depending on quality of the contact. I find it better than the plain continuity buzzer, but it's funky. The U1272A also has a really nice screen flashing option (backlight turns on), which actually works better than the buzzer. The U1273A has no such option.

I feel it should be mentioned, to the meter's advangtage, that the continuity treshold can be selected with manual ranging button, if needed.

EDIT: Perhaps that could be the reason for the more snappy response of the 1272's LCD backlight (as compared to the buzzer), i.e. backlight - fixed-treshold, simple analog comparator, buzzer - software-selectable treshold after ADC?

• Provided leads are good quality but the handle is in two parts, which makes them quite long. Nothing a good set of Fluke TL71 can't fix...

The upside being, I was able to get a pair of female shrouded banana to male unshrouded banana adapters from eBay which allows me to connect the meter direclty to my bench supply, MonsieurAdaptateur or any other gear that won't otherwise accept a shrouded plug.*)

*) Yes, I do realize I can just plug an unshrouded banana plug at the meter side just as well

[macboy]

I have a couple of U1272A's and only use them periodically
and out of all the meter's that I use it's the only one that I
find that a quick refresher course is required every time
that they come out, some of the hold down feature's are
not that intuitive unless you are using them frequently.

I keep meaning to print up and laminate a small cheat
sheet and stick in in behind the bail, maybe tomorrow.

Also nearly forgot, on my 189 and also on a twenty year old
Dick Smith meter I have the ability to latch the continuity
buzzer with a momentary contact on the probes, this is
handy when working in large complex's and factories.
Maybe there's a trick to getting it to work on the U1272A's.

Otherwise one of my favourite bit's of kit......


Muttley

Please don't pluralize word's with apostrophe's. That makes it difficult for other's to read your writing. 
Use of U1272A's is acceptable. The rest are not and serve to confuse your meaning.

[Zbig]

I will type whatever I like in any manner that I like until
a moderator say's otherwise, your the first to bitch.

Just FWIW, it annoys me no end as well and is just incorrect - plain and simple.

EDIT:
http://theoatmeal.com/comics/apostrophe 

[Wytnucls]

Foreigners make an effort to write in English properly. I don't think it is too much to ask of native speakers to do the same, if only as a sign of respect for their own language.
The upside is that over time, beginners learn the queen's English (or American) and it improves overall written communication on the site.

[Zbig]

Not all of us went to school, some of us grew up in institution's
in fact, so if you dont like it then dont read it and fuck off.

Classy.

EDIT:
When I was a kid, I had to walk to school and it was uphill both ways. I guess that's the perfectly valid reason for me, as a grownup, to insult others when they point out the errors in my use of my native language, right?

[Muttley Snickers]

If you think that my grammer is bad wait till you see my cooking..

You are welcome to go over every one of my posts, not one insult.

So I hereby retract and apologise.

[LaurentR]

Being a non-native English speaker, I'll do my best to watch my spelling 

I'll collate the positives that have been already mentioned and add them to a new section in the original post.
If you have more likes and dislikes about those DMMs, keep posting!

[Zbig]

If you think that my grammer is bad wait till you see my cooking..

You are welcome to go over every one of my posts, not one insult.

So I hereby retract and apologise.

I had to invite my friends over for a cookout so I could finally see if my kitchen works. My task was beer supply Peace! O0

[Zbig]

Also, both off and LowZ positions have a low impedance of ~1.7kOhm, be aware of this.

And when we're at it, 230V across 1.7kOhm amounts to ~30W and 1000V - almost... 600W of dissipated power!? No way. What's really going on there? Is there a PTC in series with the shunt? If that's the case, shouldn't they be mentioning the widely varying input impedance in the datasheet?

EDIT:
I'll answer this myself: yup, there is! That's probably what these several PTCs shown in Dave's teardown are doing. I've measured the Keysight's input resistance right after it was measuring mains voltage for a minute with another DMM. Sure enough, as the PTCs cooled down, the resistance dropped from several tens of kOhms to - wait for it - some 1.5kOhms, which is actually less than the initial 1.7kOhms! Go figure. I wonder if that recovery period doesn't affect other kinds of measurements.

[Zbig]

If you have more likes and dislikes about those DMMs, keep posting!

There's one more thing I find mildly annoying. My cheap and portable UNI-T UT33A emits a warning beep some time before it goes to auto-sleep so you have a chance to prevent it by pressing a button. Keysight doesn't do that - it just beeps the exact moment it's switching off. Fortunately, you can either override the APO temporarily when turning the meter on or permanently - from the menu.

[LaurentR]

Updated the original post with a bunch of new material including what has been said in this thread.

Some other comments:

- For safety reasons I am not fully understanding, the new recent firmware has a default LPF on DC measurements. I have found that this noticeably slows down the display rate and stabilization time of DC measurements. I turned it off in setup.

- I found that sometimes the mVDC range has a substantial offset (typically ~20uV, sometimes up to 50uV) that slowly drifts back to 0 in most cases. The spec clearly says the offset (20 counts == 20uV) is only with offset Nulled out, but I am surprised the offset sometimes stays for a while. I though it would be some thermal effect that goes away by itself, but no.

U1272 beep cannot be fully turned off - beeper is not completely disconnected and you can hear faint clicks in silent room. You only have option of beeps or silence (meaning only one setting for turn on beep, button beeps, continuity beep). Separate settings would be nice.

I remember the U1272A doing the faint clicks in silent mode, but the U1273A doesn't do it. I wonder if it's linked to the U1272A's backlight continuity feature (even if it's turned off).

[128er]

Some other comments:

- For safety reasons I am not fully understanding, the new recent firmware has a default LPF on DC measurements. I have found that this noticeably slows down the display rate and stabilization time of DC measurements. I turned it off in setup.

http://cp.literature.agilent.com/litweb/pdf/U1273A-01-S.pdf

[electr_peter]

If you have more likes and dislikes about those DMMs, keep posting!

There's one more thing I find mildly annoying. My cheap and portable UNI-T UT33A emits a warning beep some time before it goes to auto-sleep so you have a chance to prevent it by pressing a button. Keysight doesn't do that - it just beeps the exact moment it's switching off. Fortunately, you can either override the APO temporarily when turning the meter on or permanently - from the menu.

I actually prefer meter not giving pre-emptive warning with sound for APO. Case in point - Amprobe AM-240. It has APO turned on by default. After some time it emits super annoying beeping sound, then waits few minutes, beeps again and turns off. I hate this behaviour - just beep once before actual turn off. There is no need to inform annoy anyone that "Hey, I have reached half timer mark for APO".

- I found that sometimes the mVDC range has a substantial offset (typically ~20uV, sometimes up to 50uV) that slowly drifts back to 0 in most cases. The spec clearly says the offset (20 counts == 20uV) is only with offset Nulled out, but I am surprised the offset sometimes stays for a while. I though it would be some thermal effect that goes away by itself, but no.

Is DMM connected to something during measurement? (open leads -> random readings) Is filters turned on? Low range is sensitive to all sorts of interference pick-up, especially with long leads.

I remember the U1272A doing the faint clicks in silent mode, but the U1273A doesn't do it. I wonder if it's linked to the U1272A's backlight continuity feature (even if it's turned off).

In case of U1272A, buzzer circuit is not completely turned of in HW or SW. U1273A model probably has different buzzer circuitry because it can play melodies.

[echen1024]

Let me think...

I really like the huge resistance range, up to 300MOhm.
I really wish it would work with Agilent's amazing BenchVue software, since that is where I mostly use my DMM. I understand that BenchVue is likely meant for a bench dmm. I also dislike how it does not have a dedicated enter key or markings, which make the menus harder to navigate at first. And the ability to bisplay measurements in dB is also a really nice feature.

[LaurentR]

Let me think...

I really like the huge resistance range, up to 300MOhm.
I really wish it would work with Agilent's amazing BenchVue software, since that is where I mostly use my DMM. I understand that BenchVue is likely meant for a bench dmm. I also dislike how it does not have a dedicated enter key or markings, which make the menus harder to navigate at first. And the ability to bisplay measurements in dB is also a really nice feature.

Interestingly, the new version of the HH DMM logger software has been reskinned to looked pretty much exactly like BenchVue. I use both and it's too bad they're different products. I guess BenchVue is Visa-based, but still (the HH DMMs actually use very SCPI-like commands through a serial port, so it's not that far).

[VK5RC]

Whilst a little off a U1273, I am a big fan of oleds mainly because of the viewing angle and readability (in doors).  Happy U1253b owner (5yrs).

[nowlan]

Wasnt there an issue with the oled lifetime. Some warranty stink on the forums last year.

[VK5RC]

There was a guy with a u1253a who had it fade. I have had some contact with other u1253b guys and not heard of others having similar issues, I think MTTF of OLED is thought to be higher 2-5x compared to LCD but that is still pretty infrequent.

[sasmit]

I recently purchased an agilent U1272 in India after going through multimeter tear downs including Dave's. However it's been nothing but trouble since then, I bought it from an authorized Agilent/Keysight distributor in India. I checked the warranty of the instrument the day I bought in on keysight warranty verification page and found that the warranty was already over and it's been registered since 2012!
Moreover the multimeter has the infamous Agilent u1272 firmware issue but unlike Dave's and a lot of others it refuses to come out of its autoranging fit. I checked the firmware version it's the now infamous ver 2.00   still then my serial no does not figure in Agilent's free cable  serial number range for this issue.
I got in touch with keysight India, but haven't got any response from them regarding the expired warranty on an apparently new multimeter or the non functional unit.
I was wondering if anyone on the forum has any info no how to get through to keysight ,  I spent close to $300 on this and ended up with an orange brick 

[TheSteve]

Sounds like it was new old stock. If it was Agilent branded that is a huge clue right there. Keysight(Agilent) starts the warranty period when they manufacture the product. They generally extend the warranty 6 months from that date basically assuming the stock will be turned over(sold) within 6 months.

I would return the meter, not only is it out of warranty but the calibration on it is also over 3 years old.

[sasmit]

I recently purchased an agilent U1272 in India after going through multimeter tear downs including Dave's. However it's been nothing but trouble since then, I bought it from an authorized Agilent/Keysight distributor in India. I checked the warranty of the instrument the day I bought in on keysight warranty verification page and found that the warranty was already over and it's been registered since 2012!
Moreover the multimeter has the infamous Agilent u1272 firmware issue but unlike Dave's and a lot of others it refuses to come out of its autoranging fit. I checked the firmware version it's the now infamous ver 2.00   still then my serial no does not figure in Agilent's free cable  serial number range for this issue.
I got in touch with keysight India, but haven't got any response from them regarding the expired warranty on an apparently new multimeter or the non functional unit.
I was wondering if anyone on the forum has any info no how to get through to keysight ,  I spent close to $300 on this and ended up with an orange brick 

PM this guy, Keysight_DanielBogdan.

So the mail id would be  "Keysight_DanielBogdan@keysight.com" right ?

[sasmit]

Sounds like it was new old stock. If it was Agilent branded that is a huge clue right there. Keysight(Agilent) starts the warranty period when they manufacture the product. They generally extend the warranty 6 months from that date basically assuming the stock will be turned over(sold) within 6 months.

I would return the meter, not only is it out of warranty but the calibration on it is also over 3 years old.

Yeah tats where the problem is, the distributor has gone silent after the sale. He must also be knowing that its an NOS, but sold to me as new. I have written the same to keysight support India. Called up keysight India , but from the conversation I had it seems they are more concerned with what company I work for and very concerned if I was an individual buyer.

[sasmit]

Oh really sorry about that, somehow I thought it to be a keysight mail id. Let me PM him.

[sasmit]

Well after a month of fighting with Keysight India, writing to Daniel ( Keysight_daniel) there's no progress on this. Guess Keysight service is pathetic anywhere outside the US or Europe  and we are after all an developing nation ... who pay more for everything and get treated as if we got it for free.

I meanwhile tried to resurrect the brick by getting an USB cable spending another 50$ on an already wasted 300$, I was able to get it to firmware 3.03 but my meter is still doing strange things like Dave's original failed video. Tried various things even tried to short out the EEPROM lines while powering up to clear any stored value issues. Nothing works... it only measures continuity and current  on all other ranges it keeps on doin auto ranging with weird values. I was wondering if it's any chip on the analog front end which can be causing this, can it be fixed by replacing that chip. I don't think it's an firmware issue as I updated it to the latest firmware and it still didn't fix it.

[TheAmmoniacal]

The U1272A is a fantastic DMM, and the one I've decide to keep after trying countless others.

Pros:
- Fast visual continuity buzzer (the audible one is slow)

Cons:
- Hard to use menu system (orders of magnitude better on the U1253B)

[retiredcaps]

on all other ranges it keeps on doin auto ranging with weird values.

I don't work for Keysight, but let's get a baseline on what is happening with your meter.  Since I can't see what you are seeing, please answer the following questions (or post a youvideo showing its behaviour).

Q1) Set meter to autoranging DCV.  Measure a 9V battery. What does lcd show?  Is the reading steady or jumping all around?

Q2) Set meter to autoranging DCV.  Short the probes together.  Does it show a steady 0?

Q3) Set meter to autoranging ohms.  Measure a 1k ohm resistor.  What does lcd show?  Is the reading steady or jumping all around?

Q4) Set meter to autoranging ohms.  Short the probes together.  Does it show a steady 0?

Q5) Set meter to manual range DCV. Measure a 9V battery. What does lcd show?  Is the reading steady or jumping all around?

Q6) Set meter to manual range ohms. Measure a 1k ohm resistor.  What does lcd show?  Is the reading steady or jumping all around?

Q7) Please post clear focused pictures of your meter. We want to see both sides of the pcb and the range switch.  We want to see if there is anything obviously wrong with your pcb and/or rotary switch.

Q8) Have you or someone who may have borrowed your meter measured anything high voltage (i.e. > 240V)?

[sasmit]

on all other ranges it keeps on doin auto ranging with weird values.

Let me just answer the queries in line, I will post high res photos of my meter's pcb after I take it with a Macro lens.

I don't work for Keysight, but let's get a baseline on what is happening with your meter.  Since I can't see what you are seeing, please answer the following questions (or post a youvideo showing its behaviour).

Q1) Set meter to autoranging DCV.  Measure a 9V battery. What does lcd show?  Is the reading steady or jumping all around?
         Jumping around.

Q2) Set meter to autoranging DCV.  Short the probes together.  Does it show a steady 0?
        It shows around 25 volts with a -  sign.

Q3) Set meter to autoranging ohms.  Measure a 1k ohm resistor.  What does lcd show?  Is the reading steady or jumping all around?
       Flashes intermittently till it gets to some Nano Siemens where it stays, strangely if we switch to continuity it indicates by backlight flash but      reading stays in  nS.


Q4) Set meter to autoranging ohms.  Short the probes together.  Does it show a steady 0?
       Nope

Q5) Set meter to manual range DCV. Measure a 9V battery. What does lcd show?  Is the reading steady or jumping all around?
       Jumping around.

Q6) Set meter to manual range ohms. Measure a 1k ohm resistor.  What does lcd show?  Is the reading steady or jumping all around?
       Display doesnt change but bar graph drops to half.

Q7) Please post clear focused pictures of your meter. We want to see both sides of the pcb and the range switch.  We want to see if there is anything obviously wrong with your pcb and/or rotary switch.
 will do.
Q8) Have you or someone who may have borrowed your meter measured anything high voltage (i.e. > 240V)?
 Nope , havent been able to get it working since I bought.

[TheAmmoniacal]

Your meter is fucked

[retiredcaps]

I will post high res photos of my meter's pcb after I take it with a Macro lens.

I will await your high resolution pictures, but we can test a lot of the front end input protection to see if there is anything bad.  Using Dave's pictures at

https://www.flickr.com/photos/eevblog/sets/72157626761928610/

Q9) Check to make sure your rotary switch has all the clips present like in Dave's photo.

Q10) Give the COM and V/ohm input jack a good tug/push/pull to see if there are any bad solder joints or loose fit.

Q11) There are 4 green colored PTCs in heat shrink.  My guess is that each should measure around 500 to 1500 ohms.  Report your readings for each.

Q12) There are two gas discharge tubes RV2 and RV3.  They should measure infinite ohms (open circuit).  I can't see RV1, but if you can find that, measure RV1 as well.  Report your readings for each.

Q13) R34 might be a fusible resistor. My guess is that it should measure around 1k ohm.  Report your reading.

Q14) Check the pcb rotary switch pcb area for dirt/debris.  If it looks dirty, despite being a NOS, clean it with 91% IPA.

Q15) Using another meter, what is the input impedance of the 1272 when the 1272 is turned on and rotary switch set to DCV?  I'm guessing it should be around 11M ohm.

[retiredcaps]

I was able to get it to firmware 3.03 but my meter is still doing strange things like Dave's original failed video. Tried various things even tried to short out the EEPROM lines while powering up to clear any stored value issues.

Q16) According to the instructions, did you do step 6 (below)?  You probably did, but I just want to verify.  I didn't look at page 150 to view the instructions since I don't have any Agilent/Keysight meters at home.

6. Reset the multimeter to its Default values through the setup menu (refer to User Guide page 150). This step is mandatory.

PS. Dave's original failed video is #170.  Supposedly, these problems were fixed in firmware 2.00 as per release notes at

http://www.keysight.com/upload/cmc_upload/All/U1271_72_firmware_release_notes.txt

[sasmit]

Apologies for the delayed reply and not posting the meter board pictures.

Well out of the blue , keysight India called me on the service request and mails I sent them and decied to replace my meter " As an exception and good will measure". Its getting delivered today hopefully this isnt screwed as my earlier one.
So Keysight/Agilent came through although a bit late,  .
They are a bit slow but quite good when it comes to service and customer satisfaction.

[sasmit]

And thanks to Daniel  "keysight_daniel", I had one interaction with him on mail about this, but copied him in subsequent conversations I had with Keysight India may be that helped.

[plurn]

- For safety reasons I am not fully understanding, the new recent firmware has a default LPF on DC measurements. I have found that this noticeably slows down the display rate and stabilization time of DC measurements. I turned it off in setup.

I thought this point should be further emphasised. I recently purchased a Keysight U1272A with 3.03 firmware (hardware from Feb 2017) and I was finding it _extremely_ annoying with its _massively_ slow DC Volt readings. It kind of slowly ramps up to actual voltage over a number of seconds, rather than getting near the voltage instantly and taking a while for the less significant digits to settle as you might expect. About 5 seconds to get even close to the correct reading. Takes about 7 seconds to do an auto trigger reading even in the correct manual range or in auto range. It was very confusing behaviour and I was regretting buying it. I finally figured out this was the "Low Pass Filter (LPF) on DC" causing the issue (as you did). It is quick with "Low Pass Filter on DC" disabled so I am happy now.

Also noticed this:

Measuring DC Volts, Smooth mode enabled, plus "Low Pass Filter on DC" enabled, plus Auto Hold enabled, means Auto Hold never triggers. Well I gave up after 7 minutes waiting for it to trigger. That is close enough to never. So this combination of settings is not compatible. Not a big deal just thought I would note it.

Trying the above again but with "Low Pass Filter on DC" disabled works fine.

So Low Pass Filter is the devil - well unless you actually need it.

[plurn]

Dislikes
  -  Dark grey display background on U1272A


One other dislike I have for the U1272A. Took me a while to notice but the background grey of the display is really quite a dark grey so there is not much contrast between the display characters and the background. So I find myself straining to read it and then remember to put the backlight on - so I am very often using the backlight using up the batteries. It is quite annoying.

I have other multimeters that are cheap and don't even have backlights, but the background of the display is much lighter grey and I rarely have problems reading it unless the room is dark.

It probably does not help that my apartment is not as brightly lit as it used to be due to the government basically banning proper light bulbs in favour of less effective fluorescent replacements - but that is the situation I am in.

I wonder if the LCD polariser can be changed to a less dark one (if that is the cause of the problem)?

Note that my U1272A is a Keysight one built early 2017 - don't know if displays changed over the years.

I wish the backlight worked like the backlight on A&D SJ-WP scales (eg SJ-15KWP). These scales have comprehensive backlight settings so you can get it to turn on the backlight automatically if the reading changes and then auto turn off after a selectable timeout. Also the backlight can be on at the start without you having to turn it on, and then it can use those mentioned backlight settings. With a multimeter I suppose you could also add a tilt/motion/gyroscope sensor so if you tilt the multimeter a bit it could light up. This would allow you to have the backlight available most of the time without having to think about it - and it would only be on when you need it so it would limit wasting the battery. There you go multimeter manufacturers - you can have those ideas for free - please implement them.

Screenshot of one of Dave's videos showing how dark the display background is compared to some other multimeters. Not exactly a fair comparison as the U1272A is on a bit of an angle, but it is quite representative of the difference I notice at home when I compare it to my other multimeters:

[sasmit]

Apologies for waking up an old thread, but problems seem to find their way onto this meter. It was lying unused for sometime and one fine day I checked the  duracell alkalines had leaked. In the process the plastic for the battery holder was all crumbly and broke. I got the whole back case as replacement from keysight India and cleaned up the pcb with IPA. I powered it on but now it keeps saying "A-err" , the jack sense for current mA/A range. I did a very close inspection of the pcb and the jack sense contacts to check if any tracks shorted/corroded from the battery leak but everything looks fine.
I even re-flashed the software to make sure its not a firmware issue, it still shows A-err. Tried tracing the jack-sense tracks to the opamp where the detection circuitry is there , unfortunately its leading to a blind via  and I am not able to trace it any  further.
Really appreciate any help on this, keysight themselves quote almost the cost of a new meter for repair...rather replace with another meter.
My meter was replaced twice initially , once for the faulty firmware issue and once for the emc related issue. After the emc related replacement I could see quite a few hand soldered mods on the pcb, is this what is causing something to fail in the jack detection circuitry ?

[voltsandjolts]

Seems like you have been unlucky, I think the U1272A is the best option right now for electronics engineer handheld.

[HighVoltage]

... and cleaned up the pcb with IPA.

May be IPA is still under some components.
Wash it again with clean IPA and use a soft brush.
Then dry it in an oven at 50 degree C for several hours.

What annoys me with these meters is the sudden loud beep after a few minutes, when it goes to sleep mode.
Otherwise they are really great handheld DMM's

[rsjsouza]

In addition to HighVoltage's tips, make sure there is no corrosion or foreign material under SMD parts or even inside the massive input Jacks. A thorough cleaning with IPA (by that I mean IPA flowing down like a stream of water), a brush and use one of those compressed air cleaning sprays - the spray will not only dry the IPA but may also displace some solid material away from under SMD ICs.

Looking at Dave's hi-res photos, it seems there is a thin PCB track coming out of the middle of the 11A fuse, which may well be part of the detection circuit.

Just be careful to not "wash" the board around the display, buzzer, pots, etc. 

- For safety reasons I am not fully understanding, the new recent firmware has a default LPF on DC measurements. I have found that this noticeably slows down the display rate and stabilization time of DC measurements. I turned it off in setup.

So Low Pass Filter is the devil - well unless you actually need it.

I agree - the LPF on DC is extremely obnoxious.

[salvagedcircuitry]

I have a U1272A and one of the input jacks has sheared inside. Does anyone know where to find replacement input jacks?
Keysight has no parts available listed in Keysight Find-a-Part.

Thanks.