Author Topic: Upgrading/Unlocking Agilent Meters via EEPROM  (Read 39782 times)

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Offline logic

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Offline Technics

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #26 on: March 15, 2013, 07:19:51 am »
I asked this over on HAD. Have you checked that the extra ranges have been calibrated? I would imagine calibration of each range is done in the factory and stored in the EEPROM. I don't imagine they calibrate ranges that aren't enabled. It would be good to check EEPROM images of several meters. If all ranges are calibrated then it's a good find.  :-+
« Last Edit: March 15, 2013, 07:21:53 am by Technics »
 

Offline gnifTopic starter

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #27 on: March 15, 2013, 07:35:36 am »
I asked this over on HAD. Have you checked that the extra ranges have been calibrated? I would imagine calibration of each range is done in the factory and stored in the EEPROM. I don't imagine they calibrate ranges that aren't enabled. It would be good to check EEPROM images of several meters. If all ranges are calibrated then it's a good find.  :-+

This does not enable additional ranges, just features such as data logging. Also this meter supports calibration via the menus, so if you have the standards you could calibrate it yourself anyway.
 

Offline Teemo

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #28 on: March 15, 2013, 09:14:39 am »
All this good info certainly brought the Agilent meters to my attention. And made me think about puchasing one... This is somehow compelling to know that it is possible to activate some hidden features :). To make thing to do what it was not supposed to do.
« Last Edit: March 15, 2013, 09:17:01 am by Teemo »
 

Offline vl400

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #29 on: March 15, 2013, 09:37:32 am »
Have not done anything else with the U1732C to U1733C mod, it still thinks its a 33 but does nothing in 100KHz mode. If someone has a 31 that they can get an EEPROM dump from, or even better a 33, would make it much easier than randomly changing bytes.
 

Offline gnifTopic starter

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #30 on: March 15, 2013, 11:06:45 pm »
Have not done anything else with the U1732C to U1733C mod, it still thinks its a 33 but does nothing in 100KHz mode. If someone has a 31 that they can get an EEPROM dump from, or even better a 33, would make it much easier than randomly changing bytes.

For those that may be worried about copyright infringement by posting such a dump should not be concerned, the EEPROM only contains the device config, not the firmware :).
 

Offline BravoV

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #31 on: March 16, 2013, 12:34:30 pm »
I don't have any problem to dump content of my Agilent U1242B eeprom, as long anyone has patience and kindly enough to assist/guide me (read, a noob ee wannabe) in using my Stellaris Launchpad as logic analyzer to dump it, as this topic here -> Stellaris Launchpad Logic Analyser. Yes, I have those probes for hooking up a soic chip like vl400's photos.

Of course, you also must provide the serial number's address in order for me to overwrite it.  ;)

Offline gnifTopic starter

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #32 on: March 16, 2013, 12:37:46 pm »
I don't have any problem to dump content of my Agilent U1242B eeprom, as long anyone has patience and kindly enough to assist/guide me (read, a noob ee wannabe) in using my Stellaris Launchpad as logic analyzer to dump it, as this topic here -> Stellaris Launchpad Logic Analyser. Yes, I have those probes for hooking up a soic chip like vl400's photos.

Of course, you also must provide the serial number's address in order for me to overwrite it.  ;)

I assume you mean the address of the i2c device? If so, then it is in the datasheet. You do not need a logic analyser, just interface to the device via I2C directly while the meter is off and dump the EEPROM, alter it and flash it back into the EEPROM. I am sure the Stellaris Lauchpad has an I2C interface.
 

Offline BravoV

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #33 on: March 17, 2013, 09:03:11 am »
My problem is I dont have any dumping gadget like bus pirate or similar, while my programming skill at Stellaris only passed recently at the grade on making "Hello world !".  :-DD

About the SN address, its just for anonimity purpose before I give it to someone.  ;)

Offline vl400

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #34 on: March 17, 2013, 09:31:05 am »
My U1732C looks to have all address lines tied to ground, I didnt hook any pins to them to read and write it.
 

Offline HackedFridgeMagnet

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #35 on: March 17, 2013, 10:34:55 am »
Bravo V, use an Arduino.

I just bought one of those cheap Agilent U1242As too, $127 Au delivered. So I guess at some stage I may change the config.
 

Offline vl400

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #36 on: March 17, 2013, 12:05:51 pm »
Could be game over on the U1732C to U1733C EEPROM hack. While you can get the 33 options on the screen it wont measure anything, even with a blank EEPROM the 100KHz signal is never present. Am pretty confident it will require a hardware hack to go along with it  :--
 

Offline alexwhittemore

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Re: [SUCCESS] Agilent U1241A to U1242A hack
« Reply #37 on: April 01, 2013, 06:25:13 am »
somewhere in Agilent, and engineer is adding an encoded checksum routine to the EEPROM driver library....

I don't think Agilent needs to worry. The skill, knowledge and tools to do this are beyond the ability and motivation of 99.99% of purchasers. They are not going to lose sales over it.

That's totally, totally wrong, though! Think about it, if you're going to own an electronics multimeter that retails for between $200 and $500 US (given all the lines this affects), you DAMN well better at least understand what an eeprom is and how to use it :). Now of course, this PARTICULAR meter is more electrical than electronic, but still. The 1253 line isn't.

Anyway, more to the point, *someone already did,* else there'd be no thread. And the process is easy enough for the meter's target market to follow.

The REAL reason they probably don't need to worry is that hobbyists make up a minuscule fraction of their market, and companies aren't going to start buying the cheaper tool and spending precious employee time hack-upgrading it. Which is, of course, why these tools can command such a high retail price despite being (one can only assume based on complexity) relatively cheap to manufacture and high-margin.
 

Offline Harvs

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #38 on: June 07, 2013, 11:53:49 am »
I finally got around to doing this hack to the 1241.

Just a note the harmonic ratio function doesn't work properly.  It'll only ever display 0 or 100%, it looks like some sort of calibration data is missing (this is the sort of effect I've seen before when a meter's two point calibration are set to the same point.  Unfortunately there's no calibration procedure for it.

So if anyone with a 1242 feels incline to do a dump of the EEPROM, it would be interesting to see if there's some parts of the cal area that are used that aren't in the 1241.  Alternatively I guess I could just start changing some of the values that are currently 0xFF prior to the serial number and see if that does anything.
 

Offline millerb

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Re: [SUCCESS] Agilent U1241A to U1242A hack
« Reply #39 on: June 07, 2013, 12:21:49 pm »
[quote author=alexwhittemore link=topic=14365.msg210779#msg210779 and companies aren't going to start buying the cheaper tool and spending precious employee time hack-upgrading it. Which is, of course, why these tools can command such a high retail price despite being (one can only assume based on complexity) relatively cheap to manufacture and high-margin.
[/quote]

Companies may not make it policy to hack their gear but budget constraints can motivate employees to do it on their own time.
 

Offline Harvs

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #40 on: June 08, 2013, 09:01:51 am »
I've probed the EEPROM whilst it's in harmonic mode.  There's 4 bytes it reads out that are different to those that are read during the AC volts measurement, when in 1000mV range.  Not surprisingly they're all blank, which would be the problem.

bytes
0x80, 0x81, 0x40, 0x41

are the blank ones it's reading.
 

Offline droffsite

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #41 on: March 04, 2022, 02:21:47 am »
9 years later, just did this to a cheap U1241A I got on eBay. Used a TL866II Pro. I had to desolder the EEPROM (attempts to read in circuit kept returning FF's and 80's), but then it worked a treat. Thanks!
 

Offline JJalling

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Re: Upgrading/Unlocking Agilent Meters via EEPROM
« Reply #42 on: March 04, 2022, 08:04:24 am »
How about bench meters like the 34460A? Can they be "upgraded"?

BR Jonas
 


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