Is it by pulling the calibration memory IC?
Regards, Dieter
Dieter, I think the "floating" calibration info is saved on U12, a 48Z02 which in my unit is a Dallas DS1220Y. I saved the memory out of it with my xGecu T48 to a BIN file (which I can provide should you want it, though I think it only carries my calibrations constants).
I'm currently evaluating how I can transplant it on an FM18W08,
which seems to be a pin-compatible replacement with non-volatile memory but without a battery. My plan is to then have a full hardware backup of U12 including the current cal of the instrument. I'd then be able to recalibrate it with the capacity to go back.
Now, I hit a bit of a roadblock - I'm not 100% sure how to proceed. I programmed the FM16W08 with the DS1220Y BIN, but there seems to be more to it than I initially thought:
https://xdevs.com/fix/hp3458a_u4/#fram. Rewiring and placing of the data on the lowest bank?
If anyone reading this has completed or is familiar with the procedure, I'd appreciate some input.