Sounds like the whole RAM is battery-backed, not just the address space used
to hold calibration constants and instrument state. Is it practical to
Dremel the Dallas part open and replace its integral lithium cell with an
outboard cell?
-- john, KE5FX
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I have found that the FRAM devices are not a viable option in the
243X/40. Sadly I must report that what looked like a very promising
alternative to the DALLAS RAM/Lithium cell combo has turned out to be
a dead end.
I have been testing for over one month now on a 2430A, 2440 and 2465B
and everything seemed fine. My last test was to actually determine
the read/write frequency to the device.
It turn out a 2430A writes to the battery-backed devices as often as
once every microsecond. Since the FRAM device as a maximum of 10^10
read/write cycles (before it loses its NV capability) a quick
calculation reveals that the 2430A scope will render the FRAM device
a volatile device in one to three months.
For now I can only recommend the DALLAS (or other vendors)
RAM/Lithium cell combo pack device for use in Tek scopes.
Sorry for getting everyone's hopes up for a more inexpensive
replacement for NVRAM.
--Victor Silva
