HP 34740A display and 34702A Multimeter Modules

As men­tioned in a pre­vi­ous post on the Hewlett Packard 34702A Multimeter mod­ule, I have been look­ing for a 34740A dis­play mod­ule to pair with it. I was lucky to find a mod­ule that was in a good cos­met­ic con­di­tion and untest­ed for a rea­son­able price.

Hewlett Packard 34740A dis­play paired with a 34702A mul­ti­me­ter module
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Another ESI 250 DE Universal Impedance Bridge

ESI 250 DE unit #2
ESI 250 DE unit #2 front panel

Everyone should have at least two of these ESI 250DE Impedance bridges.

Well that was not my first thought when pur­chas­ing this unit on Ebay.
I was still hav­ing some issues with the “Internal DC” detec­tor cir­cuit on my exist­ing unit, and the price of this unit was extreme­ly rea­son­able. After dozens of hours trou­bleshoot­ing the first unit with no solu­tion, my thought was to com­pare the two cir­cuits and sal­vage parts from the new unit if necessary.

Continue read­ing “Another ESI 250 DE Universal Impedance Bridge”