[volt-nuts] 3458A Calibration Education

Chuck Harris cfharris at erols.com
Fri Nov 11 05:46:04 UTC 2011

Does your programmer have a specific setting for the Dallas chip?
The Dallas chips doen't take too kindly to having an eprom's programming
voltage applied.... which some programmers do even when reading.

-Chuck Harris

J. L. Trantham wrote:
> I have successfully modified my A5 board (03458-66505) by removing the EPROM
> (U110), the two DALLAS 1230Y NVRAM's (U121 and U122), and the DALLAS 1220Y
> NVRAM (the 'CAL RAM', U132) and installing sockets at all 4 positions.  In
> the process, I lost the data in the 'CAL RAM', the one chip I really wanted
> to archive.  The chip seemed to read differently each time I read it using
> my BP Microsystems BP-1600 Universal Programmer and was, clearly, not what I
> would have expected.  The two DALLAS 1230Y chips read consistently and I was
> able to archive their data with their data in a form I would have expected.

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