Description : Failure of wireless Point-of-Sale devices

Problem : New Point-of-sale devices failed after storage or at various times during service

Analysis : Failure was caused by the copper ion bridging of two conductors on a terminal. Copper from terminals leached out and was transported due to corrosive attack of tin-lead plating by contaminants released from uncured epoxy of a chip-on-board assembly in close proximity.

Resolution & Recommendations :

Extend epoxy curing to remove corrosive ion source.