@Bitmugger and @harryS many thanks for your contribution: I walked with a voltmeter up each pair of pins and record the cell voltages as follow: the neighbor pair has 3,9v as avarage. Pin 1-2 3,9v...6-7 3,9v 7-8 0v 8-93,9v 8-10 7,8v ...10-11 3,9v and 1-13 0v. it seems to be any demage between...