Author Topic: HP / Agilent 34401A hidden menu  (Read 26504 times)

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Offline dimmogTopic starter

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HP / Agilent 34401A hidden menu
« on: September 11, 2020, 08:48:52 pm »
i just acquired a very interesting edition of 34401A multimeter. It has some additional sub-menus in the sys menu. I attached pictures.
This meter can save their state and after next power-on it returns to this state. It has quite popular firmware 07-05-02 and hardware looks the same.
I wonder if anyone knows how to activate this sub-menu?
 
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Online J-R

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Re: HP / Agilent 34401A hidden menu
« Reply #1 on: September 11, 2020, 09:14:48 pm »
Mine has 10-05-02 and I do not have that menu.
 

Offline dimmogTopic starter

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Re: HP / Agilent 34401A hidden menu
« Reply #2 on: September 11, 2020, 09:19:37 pm »
I have several 34401A with different firmware versions and they don't have this menu either.
 

Offline NoisyBoy

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Re: HP / Agilent 34401A hidden menu
« Reply #3 on: September 11, 2020, 10:04:07 pm »
My two units have 11-05-02 and 11-05-03 (which should be the latest release).  The menu does not exist on them, it can be a handy feature, I wonder why it was removed.

I wonder if all meters with 07-05-02 has this feature.
 

Offline joeqsmith

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Re: HP / Agilent 34401A hidden menu
« Reply #4 on: September 11, 2020, 10:41:32 pm »
i just acquired a very interesting edition of 34401A multimeter. It has some additional sub-menus in the sys menu. I attached pictures.
This meter can save their state and after next power-on it returns to this state. It has quite popular firmware 07-05-02 and hardware looks the same.
I wonder if anyone knows how to activate this sub-menu?

Mine also has 07/05/02 and does not have these menus available (at least be default).  The service manual that came with the meter makes no mention of them.   

Offline dimmogTopic starter

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Re: HP / Agilent 34401A hidden menu
« Reply #5 on: September 11, 2020, 10:53:07 pm »
I have another meter with 07-05-02 without this menu.
Further more I just swapped eeprom U505 chip to my meter with 10-05-02 and hidden menu appears on it.
So it's definitely not related to firmware version. There is some option in eeprom.
 

Offline coromonadalix

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Re: HP / Agilent 34401A hidden menu
« Reply #6 on: September 12, 2020, 12:52:11 am »
same here   07-05-02     nothing past option 8


for the version 11 display FW  you need to send the meter at Keysight   to have an upgrade,  they wont sell you the FW 11  cpu
« Last Edit: September 12, 2020, 12:54:09 am by coromonadalix »
 

Offline gslick

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Re: HP / Agilent 34401A hidden menu
« Reply #7 on: September 12, 2020, 01:23:46 am »
The 07-05-02, 10-05-02, and 11-05-02 firmware binaries here contain the 9 STORE STATE, 10 RCL STATE, and 11 POWER ON menu strings. The 05-01-01 firmware binary does not.

https://xdevs.com/doc/HP_Agilent_Keysight/34401A/fw/
34401a_05-01-01-mcu_program.bin
34401a_07-05-02-mcu_program.bin
34401a_10-05-02-mcu_program.bin
34401a_11-05-02-mcu_program.bin
 
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Offline gslick

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Re: HP / Agilent 34401A hidden menu
« Reply #8 on: September 12, 2020, 01:43:39 am »
Agilent 34401A 6½ Digit Multimeter Quick Start Tutorial

https://literature.cdn.keysight.com/litweb/pdf/34401-90015.pdf

Front Panel Menu Reference
D: SYS MENU
1: RDGS STORE > 2: SAVED RDGS > 3: ERROR > 4: TEST > 5: DISPLAY > 6: BEEP >
7: COMMA > 8: REVISION > 9: STORE STATE > 10: RCL STATE > 11: POWER ON

So the menu items aren't completely undocumented, even if by default they are not accessible.
 
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Offline dimmogTopic starter

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Re: HP / Agilent 34401A hidden menu
« Reply #9 on: September 12, 2020, 01:50:15 am »
The 07-05-02, 10-05-02, and 11-05-02 firmware binaries here contain the 9 STORE STATE, 10 RCL STATE, and 11 POWER ON menu strings. The 05-01-01 firmware binary does not.

https://xdevs.com/doc/HP_Agilent_Keysight/34401A/fw/
34401a_05-01-01-mcu_program.bin
34401a_07-05-02-mcu_program.bin
34401a_10-05-02-mcu_program.bin
34401a_11-05-02-mcu_program.bin

Interesting. They also contain 'G: TEMP MENU' and 7 sub-menus for it. I've never seen 34401A with temp option activated.
 

Offline gslick

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Re: HP / Agilent 34401A hidden menu
« Reply #10 on: September 12, 2020, 02:08:03 am »
Interesting. They also contain 'G: TEMP MENU' and 7 sub-menus for it. I've never seen 34401A with temp option activated.

This 34401-90005 version of the Quick Start Tutorial does include those menu items.

https://literature.cdn.keysight.com/litweb/pdf/34401-90005.pdf

G: TEMP MENU
1: TEMP FUNC > 2: UNITS > 3: RTD TYPE 4: RTD Ro > 5: T/C TYPE > 6: THERM TYPE >
7: JUNCT TEMP
 
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Offline HighVoltage

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Re: HP / Agilent 34401A hidden menu
« Reply #11 on: September 12, 2020, 08:48:23 am »
It is a little know fact, that Agilent has produced special versions of some instruments for large customers, like the military. John Kenny confirmed this in his interview with Dave.

So, maybe this menu is built on such special customer version.
There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline coromonadalix

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Re: HP / Agilent 34401A hidden menu
« Reply #12 on: September 12, 2020, 10:59:52 am »
How can we activate this ??  is there a hack ...  ?   im willing to hack one of my 34401a  ic's   put some ic's sockets in it ...


Its a red plugs only with the blue shift button

display pcb 34401-66512   the repairable one
main pcb    34401-66501  rev B
« Last Edit: September 12, 2020, 11:37:20 am by coromonadalix »
 

Offline dimmogTopic starter

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Re: HP / Agilent 34401A hidden menu
« Reply #13 on: September 12, 2020, 05:32:52 pm »
How can we activate this ??  is there a hack ...  ?   im willing to hack one of my 34401a  ic's   put some ic's sockets in it ...


Its a red plugs only with the blue shift button

display pcb 34401-66512   the repairable one
main pcb    34401-66501  rev B

I attached dump of my U505 eeprom with 'save state' function activated.
If you have firmware version 07-05-02 or higher you can program it to your chip but your meter will require calibration thereafter.

 
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Offline coromonadalix

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Re: HP / Agilent 34401A hidden menu
« Reply #14 on: September 12, 2020, 09:36:29 pm »
are you talking about theses ? 


D: SYS MENU
9: STORE STATE > 10: RCL STATE > 11: POWER ON
 

Offline dimmogTopic starter

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Re: HP / Agilent 34401A hidden menu
« Reply #15 on: September 12, 2020, 09:37:53 pm »
are you talking about theses ? 


D: SYS MENU
9: STORE STATE > 10: RCL STATE > 11: POWER ON

Yes
 

Offline coromonadalix

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Re: HP / Agilent 34401A hidden menu
« Reply #16 on: September 12, 2020, 09:43:34 pm »
and the

G: TEMP MENU
1: TEMP FUNC > 2: UNITS > 3: RTD TYPE 4: RTD Ro > 5: T/C TYPE > 6: THERM TYPE > 7: JUNCT TEMP

how do you know if its in the eeprom bin ??
 

Offline dimmogTopic starter

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Re: HP / Agilent 34401A hidden menu
« Reply #17 on: September 12, 2020, 09:49:54 pm »
and the

G: TEMP MENU
1: TEMP FUNC > 2: UNITS > 3: RTD TYPE 4: RTD Ro > 5: T/C TYPE > 6: THERM TYPE > 7: JUNCT TEMP

how do you know if its in the eeprom bin ??

As I said, in my eeprom I have only 'store state' option.  I've never seen 34401A with active Temp menu.
 

Offline coromonadalix

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Re: HP / Agilent 34401A hidden menu
« Reply #18 on: September 12, 2020, 10:09:47 pm »
ok     :-+  thks   will try    when ill find my ic's sockets, dont know where i put them loll
 

Offline meandeev

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Re: HP / Agilent 34401A hidden menu
« Reply #19 on: September 13, 2020, 07:45:54 pm »
I´m also interested in decoding the eeprom in the 34401A!

I my experiments with the  eeprom I was able only to decode the calibration message string (the string that can be set with GPIB "CAL:STR xxxxx").
(https://www.eevblog.com/forum/repair/hpagilent-34401a-eeprom-checksums/msg950165/#msg950165)

This message-string is stored in the eeprom-bin-file at position 0x22, the checksum is in 0x4a und 0x4b, but I don´t know the algorithm :-(

Time to disassemble the ROM?  :-)

@coromonadalix: there´s no need for an adapter, if you have an eeprom-reader : https://www.eevblog.com/forum/metrology/read-and-restore-calibration-constants-from-a-hp-34401a/msg1743833/#msg1743833
 
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Online ch_scr

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Re: HP / Agilent 34401A hidden menu
« Reply #20 on: September 13, 2020, 08:04:40 pm »
Maybe dump the rom before and after enabeling the 10mA range as described here: https://www.keysight.com/main/editorial.jspx?cc=DE&lc=ger&ckey=1000001267:epsg:faq&nid=-31895.536880933.02&id=1000001267:epsg:faq
to shed some light on the poke command?
It might als point to the general area where such option bits are stored.

edit:
@meandeev:
Can you elaborate in what formate the cal string is stored, when looking at dimmog's dump there do not appear to be ASCII chars after 0x22  :-//

edit #2:
It appears to be "Packed 7bit ascii" but the offsets might vary with FW version?
I can find:
"HP034401" starting at 0x64
"EQUIP.NET" 0x72

A lot different from the dump i found on xDevs.
"HP9000" (might be coincidence) 0x18
"CAL: 35.7C; 3 Mar" 0x26
".7C; 3 Mar 1992;09" 0x2D
"ar 1992;09:33:58" 0x34
"09:33:58" 0x3B
« Last Edit: September 13, 2020, 09:13:17 pm by ch_scr »
 
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Offline coromonadalix

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Re: HP / Agilent 34401A hidden menu
« Reply #21 on: September 13, 2020, 09:58:58 pm »
the 10ma range should be stored in the eeprom ??

Im not at home ..   with this command,  is it stored until you disable it thru the other command, does it stay permanently ???

Damn   i'm intrigued by the temp measurements menu loll
 

Online ch_scr

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Re: HP / Agilent 34401A hidden menu
« Reply #22 on: September 14, 2020, 08:56:58 am »
They make it seem like the only way to remove the 10 mA range is to send the second command, and the eeprom is the logical place to store it.
Can you check what cal info string is shown on the device?

You could go crazy with some poke 24,0,1  23 or 26,27 and just see what happens BECAUSE YOU HAVE A BACKUP. DO NOT DO THIS WITHOUT CAL BACKUP. CAL MEMORY CORRUPTION IS LIKELY.

But doing just the one poke to show what bit is flipped (and IF a bit is flipped...) in the dump might shine some light.
Also storing a setting (then dump) and then changing one part of that setting and store it again (dump again) should point to the memory are where settings are stored.
And IF the state settings are stored in the eeprom at all...

edit: In the service manual the "Cal eeprom" is the only place I can find information can be stored in a persistent way by the device itself. Let's see if 10mA and state settings turn up?
« Last Edit: September 14, 2020, 09:12:39 am by ch_scr »
 

Offline razvan784

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Re: HP / Agilent 34401A hidden menu
« Reply #23 on: September 14, 2020, 09:50:18 am »
I firmly support the above advice to not go poking around without first backing up the EEPROM. That's where the calibration info is stored, because it is the only writeable memory in the device (check the schematic!).
Not only is standard cal data stored there, but also special factory cal data that cannot be restored by going through the usual cal procedure, such as the PWM DAC setting for the input switch precharge amp.
These can be altered through undocumented POKE commands, and some PEEK commands might have side effects as well.
 

Offline coromonadalix

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Re: HP / Agilent 34401A hidden menu
« Reply #24 on: September 14, 2020, 10:49:07 am »
Gonna rig something up, i have a pomona soic 8 socket,  just need to make place on my bench loll   

Need to make something to put the cpu in reset while making a eeprom dump, i dont have gpib adapters. 

Should work in serial terminal ?

I have an elnec programmer
 


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