[volt-nuts] HP 3458A Mem test 1 hight. How do you read 32K memory chips?

[John Phillips]

I do have a ni gpib-usb-hs
http://sine.ni.com/nips/cds/view/p/lang/en/nid/201586
I was hoping to remove the chip, read the data with a usb programer and
wright the data back into a new chip before installing it.
Then do a full calibration.
If the 16k chip has the cal vars what do the other 32k chips have?
Thanks for the input.
I should be able to read to read the data from a good meter with the MREAD
and wright it with a programer.

I have been using excl to read program 3458As  I will see if I can get
MREAD to work there.




On Wed, Aug 20, 2014 at 5:33 PM, Mark Sims <holrum at hotmail.com> wrote:

> You REALLY don't want to mess with that 24 pin NVRAM chip... it contains
> the calibration memory.  If you bugger the data in it,  you get to spend a
> couple of grand getting the meter back into working order.  I know a couple
> of people that did just that.
>
> The solution is to first make a backup copy of the memory contents using
> the (undocumented) MREAD command over the GPIB bus.  Poul-Henning Kamp
> figured out how to do it... buy the man a beer... even better a case of
> beer...   Search the archives for details.
>
> I just backed up all the memory in my 3 HP3458A's for when the inevitable
> BIG BAD DAY comes and the backup batteries go bye-bye.   If you happen to
> have a NI GPIB-232CV-A (or possibly a Prologix) RS-232 to GPIB converter
> and can run a DOS or WIN98 program,  I have a program that dumps the memory
> chips.  It has code for the Prologix in it,  but I've only used it with my
> a Prologix compatible unit I built... I don't have a real Prologix to test
> it with.
>
>
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-- 

*John Phillips*