agilent 3458A multimeter value

[eurofox]

if the calram is ok, you may buy the instrument, that's where the money is in.
Forget the working ram, 32k*8. Its content can be restored easily.
You need GPIB, a program to read out, desoldering tools & skills and a programmer to transfer the CALMEM to a new one. (Which you may buy easily also)

I did it successfully, Quarks and others also.

Frank

Hello Frank,

Did you write such a program?
If yes could you be so kind to share it?

Thanks for the info 

eurofox

[eurofox]

Since the instrument is locked because of the error it is not possible to know or change the GPIB address, I try with address 22 that is the factory default but no communication possible. 
I use the Agilent Connection Expert but cannot find an IVI compatible driver from Agilent only NI drivers seems to be available. 

This high tech multimeter drive me creasy     

eurofox

[alm]

Why would you need an instrument driver? It's not likely to support MREAD anyhow. Just sending ID? to its address (pretty sure the 3458A doesn't support the SCPI *IDN? command that the Agilent software probably sends by default) and it should return "HP 3458A". I haven't used the Agilent GPIB software for a long time, but I'm pretty sure it has a "send GPIB command" function somewhere. There are only 30 addresses to try.

[eurofox]

Sorry for my GPIB ignorance, I never used before and just bought a USB-GPIB interface 2 weeks ago.
Agilent explorer scan and detect the instruments connected, I have other instruments and did not give the GPIB address but detected without problem, only the 3458A seems to be an exception.

eurofox

[Dr. Frank]

Since the instrument is locked because of the error it is not possible to know or change the GPIB address, I try with address 22 that is the factory default but no communication possible. 
I use the Agilent Connection Expert but cannot find an IVI compatible driver from Agilent only NI drivers seems to be available. 

This high tech multimeter drive me creasy     

eurofox

Hi,

does that mean, that you have bought the unit and have it on your bench?
What's the vintage / date code?

The 3458A GPIB is very well designed, and can be accessed very easily, under normal conditions.
Perhaps the "agilent expert" does not work with the GPIB/USB adapter.

To find out the GPIB address, use the front panel keypad.

(For sure you have downloaded the manual already)

Choose MENU FULL. Then ADDRESS? gives you the GPIB address, ADDRESS 22 sets it to the desired one.

If the unit fails with RAM TEST High, this should happen only on power up. If you then make a RESET from the front panel, the instrument should initialize the NVRAM (32k*8 ) with default values, and should then continue without further failure (until, of course, you repower the unit).
Address 22 should be default, otherwise change it.
If the error persists, perhaps the CAL memory is affected. So skip the unit, as the calibration is affected (Once again: what's the date code of the unit, or better, of the DALLAS chips inside?).

What do you mean that the unit is "locked"? The front panel menu should be accessible.

I don't know anything about your GPIB program, neither your GPIB/USB interface.
 
I have programmed mine in Pascal, and may publish the core code of the MREAD command usage for the CAL RAM, if you have the possibility to write a program on your own, in any other language, perhaps.
I cannot provide any GPIB adapter related code, because mine is written for the ancient CEC card, not NI or else.
So you have to adapt the appropriate GPIB drivers and functions on your own.

My program writes a hex and a binary file. Latter one can be directly used for an EPROM programmer to write the data to the new chip.
It's not possible to do that via MWRITE command.

The latest firmware 9,x can be bought at agilent, see their site for details, it's listed there, related to PC board revisions.
The update for the old version (6 EPROMs) cost about 202€, the single chip version about 22€.
Depends on the vintage of your unit.

After EPROM and NVRAMs are updated, the unit will be as good as new.

Frank

[eurofox]

Since the instrument is locked because of the error it is not possible to know or change the GPIB address, I try with address 22 that is the factory default but no communication possible. 
I use the Agilent Connection Expert but cannot find an IVI compatible driver from Agilent only NI drivers seems to be available. 

This high tech multimeter drive me creasy     

eurofox

Hi,

does that mean, that you have bought the unit and have it on your bench?
What's the vintage / date code?

The 3458A GPIB is very well designed, and can be accessed very easily, under normal conditions.

To find out the GPIB address, use the front panel keypad.

(For sure you have downloaded the manual already)

Choose MENU FULL. Then ADDRESS? gives you the GPIB address, ADDRESS 22 sets it to the desired one.

If the unit fails with RAM TEST High, this should happen only on power up. If you then make a RESET from the front panel, the instrument should initialize the NVRAM (32k*8 ) with default values, and should then continue without further failure (until, of course, you repower the unit).
Address 22 should be default, otherwise change it.
If the error persists, perhaps the CAL memory is affected. So skip the unit, as the calibration is affected (Once again: what's the date code of the unit, or better, of the DALLAS chips inside?).

What do you mean that the unit is "locked"? The front panel menu should be accessible.

I don't know anything about your GPIB program, neither your GPIB/USB interface.
 
I have programmed mine in Pascal, and may publish the core code of the MREAD command usage for the CAL RAM, if you have the possibility to write a program on your own, in any other language, perhaps.
I cannot provide any GPIB adapter related code, because mine is written for the ancient CEC card, not NI or else.
So you have to adapt the appropriate GPIB drivers and functions on your own.

My program writes a hex and a binary file. Latter one can be directly used for an EPROM programmer to write the data to the new chip.
It's not possible to do that via MWRITE command.

The latest firmware 9,x can be bought at agilent, see their site for details, it's listed there, related to PC board revisions.
The update for the old version (6 EPROMs) cost about 180€, the single chip version about 20€.
Depends on the vintage of your unit.

After EPROM and NVRAMs are updated, the unit will be as good as new.

Frank

Hi Frank,

Yes the instrument is on my bench and I have an option to buy it.

Shift RESET just illuminate all segments from the display, I assume it really make a reset but return with the same "RAM TEST 2 HIGH" error.
No way to enter an new GPIB address, instrument is locked, just accept a RESET
By locked I mean that there is no way to access the menu.

Date code from Dallas NVRAM is 8936D1 and 8946M, Rev of ROM 5.3, it looks like an instrument from the 1st year of production since they start in 1989.

I assume that all calibration data is lost and it is not a good idea to buy this instrument or maybe just for 200 Euros.

I can write code in assembler, C, Basic, VB and used in the past Pascal, if you can share the Pascal code it is welcome.

Thanks for your sharing experience and support.

eurofox

[Dr. Frank]

Hard to figure out, if replacing those 3 NVRAMs will heal the unit.
Perhaps something in the hardware is faulty, also.

This LOCK is unusual, see manual for the LOCK command.

These NVRAMs do not cost that much, but if the calibration is lost, that'll be at least 500€ extra to get an official recal by agilent after your repair.
So, the risk would be on you, if you keep and try to repair.

Therefore the unit in its current state is worth about 1500€ at most, I would guess.

I append the TP code fragments.

Frank

[alm]

Agilent explorer scan and detect the instruments connected, I have other instruments and did not give the GPIB address but detected without problem, only the 3458A seems to be an exception.

Like I said, the Agilent explorer probably sends the *IDN? command to all addresses to probe for instruments. *IDN? is an SCPI command, which I'm pretty sure the 3458A doesn't support. ID? would be the equivalent 3458A command, but you'd have to send this manually. I'm not sure how likely it is for GPIB to work if the front panel controls fail, however.

[ManateeMafia]

If you press the Blue shift button and then press the - (error) key it will show the first error. The little "err" annunciator should be lit on the display.
Then you press the shift button again and then press backspace (clear) it will delete the error. Then repeat the process through all other errors.
The err annunciator should disappear after stepping through all the errors.

Write them down and post them including the error numbers. It sounds like there are more logged errors, it is probably showing the RAM Test 2 High error since it is the first failure.

I have seen similar issues with either a bad A/D converter board or AC converter board that failed POST and would not go any further, except I believe RESET was usable.

The 3458A assembly level troubleshooting guide lists the error messages and probable causes starting on page 73. It is a board level troubleshooting guide, but should give you an idea of what may be the cause of failure. Of course, power supplies are easy to test too.

[eurofox]

Agilent explorer scan and detect the instruments connected, I have other instruments and did not give the GPIB address but detected without problem, only the 3458A seems to be an exception.

Like I said, the Agilent explorer probably sends the *IDN? command to all addresses to probe for instruments. *IDN? is an SCPI command, which I'm pretty sure the 3458A doesn't support. ID? would be the equivalent 3458A command, but you'd have to send this manually. I'm not sure how likely it is for GPIB to work if the front panel controls fail, however.

From Agilent Explorer I can send a command and I try with other instruments and it is working but the unit should be know by the system at least by GPIP address and this is not working, I try manually all addresses.
The unit only accept RESET from the front panel.

Verry frustrating 

Eurofox

[ManateeMafia]

I read service note 3458A-04A that states during a power-on sequence or reset, a subroutine at location SUB 0, will run. If you have one that sets "LOCK ON" it could give you the same indication.

You can run the SCRATCH command when you get the GPIB interface working, this will delete all subroutines.

You probably don't have this issue based on the age of your NVRAM, but worth a shot anyway.

[alm]

If you want an easy scripting interface for GPIB, the EZ-GPIB software might work for you. It's a Pascal-like scripting language that's fairly popular for hobbyist instrument control on the cheap. It would be easy to write a program to loop through addresses 1-30, send ID? and read a response.

[Dr. Frank]

Agilent explorer scan and detect the instruments connected, I have other instruments and did not give the GPIB address but detected without problem, only the 3458A seems to be an exception.

Like I said, the Agilent explorer probably sends the *IDN? command to all addresses to probe for instruments. *IDN? is an SCPI command, which I'm pretty sure the 3458A doesn't support. ID? would be the equivalent 3458A command, but you'd have to send this manually. I'm not sure how likely it is for GPIB to work if the front panel controls fail, however.

From Agilent Explorer I can send a command and I try with other instruments and it is working but the unit should be know by the system at least by GPIP address and this is not working, I try manually all addresses.
The unit only accept RESET from the front panel.

Verry frustrating 

Eurofox

Well I understand the dilemma.
3458A would definitely respond to ID? with "HP3458A", but if it does not respond to ANY GPIB address..
And yep, the 3458A does not understand SCPI.

Pls. inspect the volt-nuts mailing list, April 2013.
There was the same error, RAM HIGH 1, same instrument vintage, with lockout of keyboard.
Those old firmware versions maybe leave the instrument in a totally puzzled state, if the NVRAM content is corrupted, instead of simply initializing to default parameters, what happened initially when I powered on after insertion of the fresh, blank 32k*8 RAMs. I've got late firmware 8,2.

But I don't know, what was the other solution, perhaps you ask that colleague volt-nuts.

PS: Pls. also try the TEST key, if that is accessible via keyboard.

Frank

[eurofox]

Agilent explorer scan and detect the instruments connected, I have other instruments and did not give the GPIB address but detected without problem, only the 3458A seems to be an exception.

Like I said, the Agilent explorer probably sends the *IDN? command to all addresses to probe for instruments. *IDN? is an SCPI command, which I'm pretty sure the 3458A doesn't support. ID? would be the equivalent 3458A command, but you'd have to send this manually. I'm not sure how likely it is for GPIB to work if the front panel controls fail, however.

From Agilent Explorer I can send a command and I try with other instruments and it is working but the unit should be know by the system at least by GPIP address and this is not working, I try manually all addresses.
The unit only accept RESET from the front panel.

Verry frustrating 

Eurofox

Well I understand the dilemma.
3458A would definitely respond to ID? with "HP3458A", but if it does not respond to ANY GPIB address..
And yep, the 3458A does not understand SCPI.

Pls. inspect the volt-nuts mailing list, April 2013.
There was the same error, RAM HIGH 1, same instrument vintage, with lockout of keyboard.
Those old firmware versions maybe leave the instrument in a totally puzzled state, if the NVRAM content is corrupted, instead of simply initializing to default parameters, what happened initially when I powered on after insertion of the fresh, blank 32k*8 RAMs. I've got late firmware 8,2.

But I don't know, what was the other solution, perhaps you ask that colleague volt-nuts.

PS: Pls. also try the TEST key, if that is accessible via keyboard.

Frank

Frank,

Thanks for support, I think this machine need a full service, new NVRAM, new Firmware and new calibration and I really wonder if the final cost will not be more than the market value, on ebay France at least 2 times working units sold for +/- 2000 Euros.
And finaly there could be another hardware problem as well

eurofox

[eurofox]

If you want an easy scripting interface for GPIB, the EZ-GPIB software might work for you. It's a Pascal-like scripting language that's fairly popular for hobbyist instrument control on the cheap. It would be easy to write a program to loop through addresses 1-30, send ID? and read a response.

Hi Alm,

Thanks for the link I will try this tool.


eurofox

[eurofox]

Hello Volt Nuts,

Update of the HP3458A story.

I would like to thank Quarks for he’s kind support    and all others 

I could manage finally to get the instrument.

It is in a fair cosmetic condition, only small usage marks, after removing all labels and glue from calibration labels, the front panel is in mint condition. I hate all those labels on the front panel and sometimes when the instrument is defect they put it on the display. 

The LTZ1000 is covered by a plastic cap, is this done on all HP3458A because I could find some pictures on the net with the option 002 with this kind of protection?

I order 1 DS1220 and 2 DS1235Y, I will change them to DS1230Y.
I order a Geller Lab SVR-T that is on he’s way to spend one week in our customs.
I order a 10K resistor 0,005% / 0,05ppm/°C

I removed the 3 NVRAM without problem with my iron with pump, easy job, just 2-3 minutes for 1 NVRAM, no damage on PCB *.
Put 3 industrial gold plated sockets and solder them on the PCB and clean it.

I checked the DS1220Y by reading with my eprom programmer and is virtual empty, just a few random values. By using the test function it give an OK

I don’t really know what they do in the testing procedure, I suppose reading content, saving it to put back after test, writing FF, reading again and comparing if it is the same and write back the saved data.

By testing the 2 DS1235Y my programmer report that one is bad at a specific address. 

I got the ordered DS1220Y from Germany last week and put it in place  , still waiting for the DS1235Y from UK. 

I try to put the DS1235Y(s) back and depending of the position it give me an error HIGH or LOW and it could be logic if one is bad and detected by the test procedure.

I upgraded the firmware as well but nothing changed, instrument is still only accepting the SHIFT and RESET function.
I hope that there is no other issue after adding the 2 NVRAM.

I intend to do the following to calibrate it:

1/ I have 2 calibrated in metrology lab 6,5 digits meter, Agilent and Picostest (They have similar specifications), I have a DER DEE for the resistor test.
2/ I will measure the value (after warm up) of the resistor with the 2 6,5 digits meter and the DER DEE and make an average and this value with the resistor will be used to calibrate the HP3458A.
3/ Start the calibration with the copper wire, the 10V reference from Geller lab and the 10K precision resistor.
4/ I hope that this should finalize it. I will check the Agilent notes about the instrument.

I will update when I get the 2 missing NVRAM.

* Used wrist strap and safe table connection to ground.

eurofox

[ManateeMafia]

I am pretty sure all cal constants are stored on the DS1220. You will be able to verify that when you run through the calibration procedure.

I have seen the plastic caps on both the standard and opt002 reference boards. Look on the board for the part number. The standard reference is 03458-66509. The opt002 is 03458-66519.

You can skip the SCAL procedure unless you have a stable ac reference. It will be difficult to cal the ac unless you have a good source.

How do the power supplies look? Hopefully the unit did not spend a lot of time gathering dust.
If so, it could take about 6 weeks of sitting idle for the reference to settle down. There was an app note from HP on this. I cannot remember which one, I am not at home to give you the specifics.

[eurofox]

I am pretty sure all cal constants are stored on the DS1220. You will be able to verify that when you run through the calibration procedure.

I have seen the plastic caps on both the standard and opt002 reference boards. Look on the board for the part number. The standard reference is 03458-66509. The opt002 is 03458-66519.

You can skip the SCAL procedure unless you have a stable ac reference. It will be difficult to cal the ac unless you have a good source.

How do the power supplies look? Hopefully the unit did not spend a lot of time gathering dust.
If so, it could take about 6 weeks of sitting idle for the reference to settle down. There was an app note from HP on this. I cannot remember which one, I am not at home to give you the specifics.

I will check the option 002 based on the number you provide.
I have Fluke 510A AC Reference Standard that I have fixed and calibrated with my Agilent 6 1/2 digits, I can use this one if needed.
The unit is totaly clean inside virtual no dust at all.

eurofox

[TiN]

The LTZ1000 is covered by a plastic cap

That is not for protection, that's for temperature stabilization. Plastic cover is working similar to simple thermostat, to reduce temperature variation of reference.

Show us some nice internal pics

[Dr. Frank]

Hello Volt Nuts,

The LTZ1000 is covered by a plastic cap, is this done on all HP3458A because I could find some pictures on the net with the option 002 with this kind of protection?

I order 1 DS1220 and 2 DS1235Y, I will change them to DS1230Y.
I order a Geller Lab SVR-T that is on he’s way to spend one week in our customs.
I order a 10K resistor 0,005% / 0,05ppm/°C

I checked the DS1220Y by reading with my eprom programmer and is virtual empty, just a few random values. By using the test function it give an OK

By testing the 2 DS1235Y my programmer report that one is bad at a specific address. 

I try to put the DS1235Y(s) back and depending of the position it give me an error HIGH or LOW and it could be logic if one is bad and detected by the test procedure.

I upgraded the firmware as well but nothing changed, instrument is still only accepting the SHIFT and RESET function.
I hope that there is no other issue after adding the 2 NVRAM.

I intend to do the following to calibrate it:

1/ I have 2 calibrated in metrology lab 6,5 digits meter, Agilent and Picostest (They have similar specifications), I have a DER DEE for the resistor test.
2/ I will measure the value (after warm up) of the resistor with the 2 6,5 digits meter and the DER DEE and make an average and this value with the resistor will be used to calibrate the HP3458A.
3/ Start the calibration with the copper wire, the 10V reference from Geller lab and the 10K precision resistor.
4/ I hope that this should finalize it. I will check the Agilent notes about the instrument.

I will update when I get the 2 missing NVRAM.

eurofox

The LTZ1000A reference inside the HP3458A always has two plastic caps assembled, one on component side, one on soldering side, see picture. That's intended for thermal shielding. The references on the web without those caps need urgently an external case for shielding.

The DS1220 contains all calibration constants (253 EA, artifact calibration and autocal constants, see listing in cal manual, CAL? command).
This RAM is protected against erroneous writing, but the content can be read by undocumented MREAD command.

The DS1230/1235 RAMs store configuration information and macros.
And most important, this 32kx16 RAM space is the working RAM memory for the 68HC000 processor.

Therefore, if one of the RAMs has a hardware error, as you obviously determined by your programmer, the processor may get stuck.
At which memory location the error is detected?

Therefore, replacing them may really heal the problem.

If you also upgraded the firmware (ver. 9,x?), which removes many bugs, then you will have a very fine refurbished box.

Your description, how you want to calibrate the unit, is ok, but it's a fact that you will have lost accuracy of DCV and OHM , and also high frequency calibration (above 100kHz VAC).

Therefore, I hope you have not payed more than 2000€, better less, as the calibration data are lost.

Frank

[eurofox]

Hello Volt Nuts,

I still wait for the NVRAM from UK  , they promise to send me a new set free of charge.

@ TiN : I will make some pictures when the NVRAM’s arrive.
@ Frank : Picture of the error of the NVRAM in attachment, I copy the data from another working HP3458A into the new DS1220Y, this way I should have basic calibration data that of course is not from my instrument. Firmware is upgraded to 9.x.

I exchange the instrument with a working oscilloscope (I have 4 other scopes  ), if the instrument is working with the NVRAM and no other problem it is a good deal  , if not it is a very bad deal.

With respect to AC calibration I have all the instruments/tools needed just missing the thermal converter.
If I understood right what those thermal converters are doing is just converting the AC RMS into a DC value that is read by the instrument.
There are many discussions about converting RMS by mathematics or by this thermal system (resistor + thermocouple)
I have an idea of an alternative using a generator, a 6 ½ digits meter and a DC calibrator.

Connect the generator to the 6½ digits meter in AC, connect the DC calibrator to the HP3458A, follow the procedure from the calibration manual with the 3 VAC, 1VAC …. On the different frequency’s, put the value from the DC calibrator according the value from the 6½ digits meter.
I think worst case I will have an accuracy that is similar to the 6 ½ digit millimeter. I could use as well the output level from the generator but I suppose the HP meter will be more accurate.
If you have comment on the procedure please comment.

I got an email today from Agilent, they charge 623,08 Euros + 60 Euros for the carrier to pick-up the instrument + VAT.
Agilent is very dynamic over here, usually you get an answer on email in one hour and they are very service minded, already got free of charge a part of an instrument.

eurofox

[ManateeMafia]

The AC calibration requires a 100KHz, 2 MHz, and 8MHz reference. If your 6.5 digit meter is not spec'd for that input range, you probably won't want to waste your time with those steps.

You are not forced to do all the AC cal steps, but if you already have access to another 3458A, use it as a transfer standard. If not, just do the DC and resistance checks, then run ACAL AC.
If it passes, check the meter with whatever AC source you have for sanity checks. Some other people have had limited success with signal generators like the HP 3325A , but if you are already considering the Agilent cal, test the meter as best you can. Agilent will do the rest.

[Dr. Frank]

oK, the error is at 0805, that's a low address, I assume in the area the µP normally uses as working space. The setup and key programming will be on higher addresses.

I assume, the firmware tests the working space area for errors on bootup (test pattern R/W), and the setup area for integrity only.
After finding defect RAM cells, the instrument will go into hold mode, to not endanger the operation.

And I confirm exactly, what ManateeMafia already wrote.

Better let the instrument initialize the CALRam with default values, then calibrate as good as possible 10V and 10kOhm, and that's it.
Any other 6,5 digits instrument will not work at 2/8Mhz sufficiently well.

And the problem has nothing to do with the A/D of alternating signals, it's the AC preamplifier, which is calibrated by the SCAL commands.

The 3458A is very precise up to 100kHz without SCAL, and may measure accurately down to 20ppm or even better at audio frequencies, if you use e.g. Gods Program from agilent , written by Swerlein.

So, if you don't need ACV at frequenciy >100kHz, better leave the RAM alone.

I think, copying cal data from another 3458A might worsen things.

Frank

[Dr. Frank]

I order 1 DS1220 and 2 DS1235Y, I will change them to DS1230Y.


eurofox

Hello eurofox,

I hope you have ordered the DS1230Y - 150+, not the terminated DS1235Y?
You would either get"old", not "fresh" ICs, or it would be very difficult for the distributor to even source it.

Or did you order at MAXIM UK directly?

Recently, Maxim UK had 10 weeks lead time for the DS1230Y, so a colleague volt-nuts ordered instead at Mouser, who delivered within 1 week.

Frank

[eurofox]

Frank,

I order them from a supplier in UK, according the tracking number I should get them next Monday.

With respect to the calibration on the analog part I will follow your advice, I check the 6 1/2 digit meter and is not supporting AC in the requested frequency range for the calibration.

I just have to put the missing NVRAM and cross my fingers.

I will update next Monday when I get the NVRAM.

eurofox