When batteries charging does not give a positive result (after some dozen hours, the charge indicator is still on) or when the replacement of primary batteries is ineffective ("LB"indicator is on), the contact inside the handle( battery container) must be clean with maintaining cleaner for electrical contact in aerosol.
If the cleaning of contact does not work it means that the batteries or the tester damaged.
during the guarantee period the user may replace only spare part delivered without of guarantee right.
note:after replacement of electronic components and magnetic circuit element in most cases tuning of system is necessary