Products > Test Equipment
HP / Agilent 34401A hidden menu
jogri:
The missing 1 kV spec is probably due to the fact that designing a board with screw terminals for 40 individual channels that has to withstand 1 kV between two screw terminals would be a nightmare (and those 40 wires would be running through a 1 cm^2 opening)... And since not that many people need to monitor multiple 1 kV lines simultaneously they just went with 300 V max instead. Also, it only goes up to 1A, probably for a similar reason.
Btw, i just checked the service manual for parts numbers and i found this entry for what seems to be the main IC on the DMM board: "U102 CUST R NET PKG, REPLACES 34401-67901"
I have the EEPROM for the chip with the calibration constants if you want it, but i doubt that it'll be usefull in this case.
ch_scr:
--- Quote from: jogri on September 24, 2020, 05:47:32 pm ---The missing 1 kV spec is probably due to the fact that designing a board with screw terminals for 40 individual channels that has to withstand 1 kV between two screw terminals would be a nightmare (and those 40 wires would be running through a 1 cm^2 opening)... And since not that many people need to monitor multiple 1 kV lines simultaneously they just went with 300 V max instead. Also, it only goes up to 1A, probably for a similar reason.
Btw, i just checked the service manual for parts numbers and i found this entry for what seems to be the main IC on the DMM board: "U102 CUST R NET PKG, REPLACES 34401-67901"
I have the EEPROM for the chip with the calibration constants if you want it, but i doubt that it'll be usefull in this case.
--- End quote ---
If you have a eeprom dump please post it, and your firmware revision.
jogri:
--- Quote from: ch_scr on September 24, 2020, 06:23:47 pm ---If you have a eeprom dump please post it, and your firmware revision.
--- End quote ---
As i've said i only have the EEPROM dump of the F-RAMs that contain useless stuff... The 34970 has its DMM on a separate module, and that module alone contains at least two ICs plus one FRAM for the cal. constants, and another FRAM on the main board that keeps track of the power cycles. Since none of those ICs are socketed i really don't want to screw around with them.
I've attached the fram dumps (had that because the one in my unit died and i couldn't format those chips via GPIB). The DMM is from the fram on the DMM module, but i wouldn't count on it being correct since one bit toggled between two states every time i read the chip... The other dump is from the fram on the main board that contains god knows what (number of power cycles+ other stuff).
Firmware rev? Can check that when i get my 34970A out of its natural habitat in a test rig where it's sitting as a rather overqualified temperature logger (i "definitely" need a 6.5 digit DMM to measure 3 digit values...)
ch_scr:
Murphy says it's propably the one you left out, what you posted looks nothing like the 34401A one's as well. :-//
ian.ameline:
Reading the scpi manuals for other HP products, DIAG:PEEK takes an address and a number of bits to read. I bet we can dump the non volatile memory by peeking addresses 0 through 512. The docs were clear that PEEK is a read-only operation.
It would be interesting to see if the data produced by that matches what people have grabbed directly off the eeprom chip. If it does match, then we could experiment with poking around near address 25 to see if we can enable the temp menu and other hidden functionality without clobbering calibration values in the 512 bytes of non volatile storage.
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