SALEM – A Boston man already facing drug trafficking charges in Lynn was arraigned on firearm and an additional drug trafficking charge Friday in Salem Superior Court.Ernest Partin, 22, of 57 South Chanlame Terrace, Boston, pleaded not guilty to trafficking over 28 grams of cocaine and illegal possession of a firearm before Judge Howard J. Whitehead.Bail of $15,000 cash was set and the case continued to Nov. 26 for a pretrial conference.Charges stem from Partin’s arrest in Lynn on April 12 when he was arrested on Allen Avenue in a black Dodge Stratus in which police suspected drug activity.Lynn Police Officers Ed Tansey and Craig Fountain reportedly found a .25 caliber handgun and approximately 45 grams of cocaine inside the trunk of the vehicle.At the time, Partin was out on bail on a 2006 drug case pending in Superior Court in connection with his arrest on July 25 when police seized 18 grams of cocaine from another vehicle on Albany Street, near the Welcoming Elementary School, which he denies.Partin is facing a minimum mandatory eight years in prison on the two drug trafficking charges, a two-year mandatory sentence on the school zone violation and another year for illegally carrying a firearm without a license. In essence, he is facing a minimum mandatory of 11 years in state prison if convicted on all four charges.Assistant District Attorney John B. Brennan is assigned to prosecute both cases.