ESI 252/253 Impedance Meter Part Number request
 

Hello,

New to the group. I purchased an ESI 253 autoranging digital impedance
meter at the Lawrenceville Hamfest (252 with autorange feature added).
It is missing a 4-pin component U2 with a heat sink tab to the
motherboard. The location of the component can be seen in a diagram on
page 48 of an on-line manual located at

http://www.tegam.com/pdf_files/MANUALS/253_MAN.pdf

Anyone know the identity of this component? Could not find schematic on
line and it is not available from mfgr.

Tnx

Mark in Atlanta