Products > Test Equipment
HP / Agilent 34401A hidden menu
ch_scr:
This "Memory Information and Procedures" also clearly states that ALL non volatile storage is in the eeprom.
https://www.keysight.com/upload/cmc_upload/All/34401A_Mem_external.pdf
iMo:
fyi - the above calmsg.zip downloads and builds here (Win10).
My HP's rev fw is 10-05-02 and no menu 9 and above.
Would be great to enhance the fw (without deleting cal constants).
PS: the doc above says the operating system is in an OTP ROM (one time programmable), but the service manual (Agilent) shows in the schematics AM27C020 which is an EPROM.
Below the BOM from the same service manual - the U502 is an M27C2001 "2Mbit OTP ROM" (aka 34401-88806). But the M27C2001 is an EPROM afaik.. :-//
It could be the older - pre 1999 "HP" models - are using OTP ROM there, later models (Agilent, KS) have replaced it with an EPROM..
The CAL constants and a few other I/O parameters are stored in an EEPROM (U505).
jogri:
Those menu items look awfully similar to the ones on my (HP) 34970A, a DMM that's also made by HP/Agilent and that's basically a 34401A with a multiplexer connected to it. Wouldn't surprise me if they use the same firmware and just added the capability to switch between different channels for the 34970A (the 34401A already kinda has that with its 4 wire measurements). In a 34970A, the store state/recall state options are to save different channel configurations and the power on option configures if the DMM should continue scanning its channels after a blackout or abort the scan. Also, it definitely has a TEMP menu, but i can't recall the exact names of the options there, but there are quite a lot (types, temp units, int/ex ref (and the temp of the ext reference), etc).
So it could be the case that some 34401A are running on software designed for the 34970A...
gslick:
--- Quote from: imo on September 24, 2020, 08:11:43 am ---PS: the doc above says the operating system is in an OTP ROM (one time programmable), but the service manual (Agilent) shows in the schematics AM27C020 which is an EPROM.
Below the BOM from the same service manual - the U502 is an M27C2001 "2Mbit OTP ROM" (aka 34401-88806). But the M27C2001 is an EPROM afaik.. :-//
It could be the older - pre 1999 "HP" models - are using OTP ROM there, later models (Agilent, KS) have replaced it with an EPROM..
--- End quote ---
An EPROM in a plastic package as used in the 34401A instead of a ceramic windowed package is an OTP part. Can't reprogram it if there is no way to erase it.
coromonadalix:
--- Quote from: jogri on September 24, 2020, 10:40:31 am ---Those menu items look awfully similar to the ones on my (HP) 34970A, a DMM that's also made by HP/Agilent and that's basically a 34401A with a multiplexer connected to it. Wouldn't surprise me if they use the same firmware and just added the capability to switch between different channels for the 34970A (the 34401A already kinda has that with its 4 wire measurements). In a 34970A, the store state/recall state options are to save different channel configurations and the power on option configures if the DMM should continue scanning its channels after a blackout or abort the scan. Also, it definitely has a TEMP menu, but i can't recall the exact names of the options there, but there are quite a lot (types, temp units, int/ex ref (and the temp of the ext reference), etc).
So it could be the case that some 34401A are running on software designed for the 34970A...
--- End quote ---
Could be it, the 34970 has the same asics, and go up to 300v not 1kv .... never saw any leaked eeprom / roms / firmwares ?
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