[volt-nuts] HP-419 and Fluke 845 Modifications

[Randy Evans]

I am looking at modifying my (defective) HP419A and Fluke 845A Null meters
using the LTC2054 zero drift op amp.  I am planning on using a single 4.2 V
Lithium Ion battery to power them (no AC input required and may not
include, TBD).  The LTC2054 has a very low bias current of typically 1pA at
room temp and the bias plots vs. temp  show no appreciable increase until
about 50C.  Conceptually, it looks pretty straight forward and, based on my
Fluke 887A modifications, likely will be very stable.

Since this is a very astute group, does anyone have any comments on the
feasibility of this modification before I get too involved?

Regards,

Randy Evans