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

--- Quote from: sasmit on July 15, 2016, 10:15:25 am ---I will post high res photos of my meter's pcb after I take it with a Macro lens.

--- End quote ---
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:

--- Quote from: sasmit on July 14, 2016, 07:18:55 am ---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.

--- End quote ---
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:

--- Quote from: LaurentR on April 24, 2015, 05:03:39 am ---
- 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.


--- End quote ---

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.
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