Operating since 2004, the Pierre Auger Observatory has led to major advances
in our understanding of the ultra-high-energy cosmic rays. The latest findings
have revealed new insights that led to the upgrade of the Observatory, with the
primary goal of obtaining information on the primary mass of the most energetic
cosmic rays on a shower-by-shower basis. In the framework of the upgrade,
called AugerPrime, the 1660 water-Cherenkov detectors of the surface array are
equipped with plastic scintillators and radio antennas, allowing us to enhance
the composition sensitivity. To accommodate new detectors and to increase
experimental capabilities, the electronics is also upgraded. This includes
better timing with up-to-date GPS receivers, higher sampling frequency,
increased dynamic range, and more powerful local processing of the data. In
this paper, the design characteristics of the new electronics and the enhanced
dynamic range will be described. The manufacturing and test processes will be
outlined and the test results will be discussed. The calibration of the SD
detector and various performance parameters obtained from the analysis of the
first commissioning data will also be presented