Page 1: ...eas between the electrodes could be reached by dirt the large double membrane Systems of U 67 U 87 A i SM 69 SM 69 fet USM 69 i IJ 47 fet after a long period of Operation noise voltages may occur For...
Page 2: ...ve to be exchanged Cleaning the membrane by means of solvents is not allowed These solvents are too thinly liquid and fugitive For careful cleaning then no time remains and inhomogenit on the membrane...
