Author Topic: U1273A  (Read 490 times)

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Offline edmundopt

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U1273A
« on: December 02, 2017, 04:48:02 AM »
Hi
 my multimeter is malfunctioning, is out of warranty and according to Keysight reply I must send it to the place where I purchase it from.
 I am going to do some measuring first, maybe I can have a better understanding of what failed
 after some search, most of topics are buy/sell/firmware update fail
 
 here is a small video with the issue : ( its not listed and it can only be accessed from this link)
 as you can see in Volts/miliVolts range almost all functions are available, you can not however get into the menu

 Ohms range and capacitance do not work, better watch video

  I am asking for help where to start measuring it
 

Offline Samogon

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Re: U1273A
« Reply #1 on: December 02, 2017, 06:29:33 PM »
Is there dirty key contacts and rotary switch or it is shades on the picture? Dirty contacts can play wierd games with meter.
 

Offline edmundopt

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Re: U1273A
« Reply #2 on: December 03, 2017, 06:05:42 AM »
I have cleaned them all, including keyboard
I've uploaded new pictures without flash

I connected bluetooth unit, so the meter recognizes position : 3; 4; 5; 7; 9; 10

so, something is wrong with it recognizing the position 1 2 and 6, wich are the ones that are really bad

any idea what is the chip that provides info to the controler of the rotary position ?
 

Offline Samogon

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Re: U1273A
« Reply #3 on: December 03, 2017, 06:45:24 AM »
Usually it is MUX/DEMUX chip like BU4051 or similar
 

Offline Samogon

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Re: U1273A
« Reply #4 on: December 03, 2017, 06:57:50 AM »
I have same meter and love it, may be i open it to see what inside and make reference measurements.
 

Offline saturation

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Re: U1273A
« Reply #5 on: December 03, 2017, 09:09:36 AM »
How did the meter fail?  Did the meter malfunction spontaneously ?  Were you measuring line voltage at the time?

Best Wishes,

 Saturation
 

Offline edmundopt

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Re: U1273A
« Reply #6 on: December 03, 2017, 10:51:56 AM »
How did the meter fail?  Did the meter malfunction spontaneously ?  Were you measuring line voltage at the time?

This is my bench multimeter, 100% of its job is in ohms/milivolts measuring battery(3.3, 5v, sometimes 12) powered devices, never touched line
battery was low, it auto turned off, I put new fresh batteries and that was it, it was all over the place.

going to search for the chip and maybe reverse engineer the path to it
 

Offline Samogon

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Re: U1273A
« Reply #7 on: December 03, 2017, 11:12:32 AM »
Hmm looks like FW glitch
Try set it to default via setup menu
 
The following users thanked this post: saturation

Offline edmundopt

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Re: U1273A
« Reply #8 on: December 03, 2017, 02:10:26 PM »
Hmm looks like FW glitch
Try set it to default via setup menu
First thing I tried to do, but look at me pressing setup buton for more then 1sec, it beeps but it does not get in, in any range.
I searched the board for a hard reset, can't find any, also via terminal (u1177a) the command is not known on "the internet" :/

Enviado do meu LG-D855 atrav├ęs de Tapatalk

 

Offline saturation

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Re: U1273A
« Reply #9 on: December 03, 2017, 10:30:29 PM »
Ouch, this does sound like a firmware issue, either as a bug or hardware fault.
The likely solution is reflashing the firmware if you can get to the menu, but if its a hardware fault then it may not be user repairable.  Best of luck, sorry to hear.

How did the meter fail?  Did the meter malfunction spontaneously ?  Were you measuring line voltage at the time?

This is my bench multimeter, 100% of its job is in ohms/milivolts measuring battery(3.3, 5v, sometimes 12) powered devices, never touched line
battery was low, it auto turned off, I put new fresh batteries and that was it, it was all over the place.

going to search for the chip and maybe reverse engineer the path to it
« Last Edit: December 03, 2017, 10:32:55 PM by saturation »
Best Wishes,

 Saturation
 

Offline Samogon

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Re: U1273A
« Reply #10 on: December 03, 2017, 11:20:01 PM »
Well, if FW is in the separate flash chip we potentially can write good FW.
 

Offline Samogon

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Re: U1273A
« Reply #11 on: December 03, 2017, 11:35:50 PM »
Wait, do you have IR pc cable for it? If so download FW update ftom keysight site and try to refresh FW
 

Offline edmundopt

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Re: U1273A
« Reply #12 on: December 05, 2017, 07:34:15 AM »
because of the chance of completly bricking it due to firmware update fail, I will first complete the reverse engineering of how the microcontroler reads the rotary switch position
I should complete this today, and then I will update firwmare, or atempt to
 

Offline Samogon

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Re: U1273A
« Reply #13 on: December 05, 2017, 05:39:29 PM »
Sure it is your meter. ;)
 


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