Tests and investigation towards the final design of the GEM front-end electronics

During the second long shut-down of the LHC, the first endcap station of the CMS muon system will be upgraded using Triple Gas Electron Multiplier (GEM) detectors. In order to gain first operational experience, a limited number of chambers has been installed in January 2017 as a "slice test" of the upgrade. During the slice test, irreversible channel loss in the test version of the front-end electronics has been observed. In order to understand the origin of such channel loss, and to verify whether this problem arises also for the final frontend electronics, a measurement campaign has been launched in June 2018. The experimental conditions faced at CMS have been reproduced in the laboratory in order to investigate different causes of the channel loss: detector mis-configuration, high- energy deposits of minimum ionizing particles, highly ionizing particles and photon background. The channel loss has been correlated with propagating discharges to the anode plane. In this contribution we show a procedure to detect channel losses in the front-end readout electronics, the experimental setup used to investigate the different hypothesis and some preliminary results.