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

[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.