AGILENT 34401A EEPROM U502

[lionelkjh]

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!

[lionelkjh]

Good evening; I also forgot to ask you if we can rewrite in this memory model??

[Qw3rtzuiop]

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.

[lionelkjh]

Good morning; Thank you for the feedback; but among the list, how to know which one is adapted to the software of mine (2006)

[Hydron]

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.

[lionelkjh]

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.....

[lionelkjh]

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??

[Wallace Gasiewicz]

Lionel:
I hope I Understand your question

The 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 installed

E= erasable (UV)
EE= electronically erasable
OTP= one time programmable
PROM= programmable read only memory

[R-1125F]

This might help identify your firmware.  https://xdevs.com/doc/HP_Agilent_Keysight/34401A/fw/readme.txt.txt

Firmware versions are here https://xdevs.com/doc/HP_Agilent_Keysight/34401A/fw/

[lionelkjh]

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???

[Hydron]

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.

[lionelkjh]

D; the calibration and the calibration constants of this device is stored by the 93C66 (U505)