AGILENT 34401A EEPROM U502 - Page 1
Forum section: electronics / general

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 07, 2023, 01:49:46 pm
content: Hello everyone! I am looking for the content of the U502 memory on the main map of the Agilent Multimetre 34401A (version of the year 2006); The EEPROM is the Ref: M27C2001 (Box: PLCC32); And I made photos of the original software agilet as well as the front panel ..... A big thank you to the one who can help me !!!! Thank you for you precious help!

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 07, 2023, 06:04:52 pm
content: Good evening; I also forgot to ask you if we can rewrite in this memory model??

author: Qw3rtzuiop
author_rank: Frequent Contributor
timestamp: March 07, 2023, 07:03:46 pm
content: U502 contains the fw. There are various revisions available here:https://xdevs.com/doc/HP_Agilent_Keysight/34401A/i would suggest staying with your current version. The M27C2001 is a OTP eeprom. You need to buy a new one. I would recommend a flash version which is re programmable like a 39SF020.

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 08, 2023, 07:26:43 am
content: Good morning; Thank you for the feedback; but among the list, how to know which one is adapted to the software of mine (2006)

author: Hydron
author_rank: Super Contributor
timestamp: March 08, 2023, 08:11:22 am
content: Going by the look of the front panel you'll probably want the latest FW (11-xx-yy), though I'm confused as to why you want to change it - is the IC dead or something? Also is it really a 2006 unit - mine is 2007 and looks older (square buttons)!While you are in there, I'd suggest taking a copy of the EEPROM data unless you want to risk your calibration constants in the off chance that the FW is not exactly the same version and doesn't like the contents.

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 08, 2023, 08:20:50 am
content: Good morning; my 34401A is faulty (starts with 1 beep, all the display segments appear; then goes out with 1 beep), and I would like to have the contents of the eeprom U502 because I would like to compare the contents.... .. Yours is an older version, because the buttons are square, not round like mine.....

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 08, 2023, 12:06:15 pm
content: Good morning; in this list which one is compatible with the photo label version?? If none seem to be the same; could someone empty the contents of the eeprom in bin format??

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: March 08, 2023, 12:23:04 pm
content: Lionel:I hope I Understand your questionThe OTP (PROM) is one time programmable read only memory and the program is set at production (one time).The EPROM is erasable and programmable, Uses UV light to erase.The EEPROM is electronically erasable, does not need a UV eraser. You just plug it in in while it is on the board if there is a connector for this.Otherwise they do the same thing and results are dependent on the programs installedE= erasable (UV)EE= electronically erasableOTP= one time programmablePROM= programmable read only memory

author: R-1125F
author_rank: Regular Contributor
timestamp: March 08, 2023, 01:26:19 pm
content: This might help identify your firmware.https://xdevs.com/doc/HP_Agilent_Keysight/34401A/fw/readme.txt.txtFirmware versions are herehttps://xdevs.com/doc/HP_Agilent_Keysight/34401A/fw/

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 08, 2023, 05:13:37 pm
content: Good morning; yes for the different eproms: but in my specific case: how to be sure of the program; because not having the same version; they are different???

author: Hydron
author_rank: Super Contributor
timestamp: March 08, 2023, 05:34:14 pm
content: Honestly I'd start with not just ripping out the FW ROM assuming that it's the problem. Have you gone through the service manual etc, or done any other troubleshooting?I'll repeat again though, the latest FW (seen on meters as early as 2005 according to the txt linked above) should be fine for such a recent meter, just backup the actual EEPROM (8-pin serial device, NOT the OTP ROM that you're calling the EEPROM) to make sure you don't lose cal constants on the off chance that something goes wrong. The ROM actually has version 11 on the sticker, like the one I suggested you use.

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 08, 2023, 05:54:46 pm
content: D; the calibration and the calibration constants of this device is stored by the 93C66 (U505)