SALEM – A Superior Court judge has set $15,000 cash bail for the 16-year-old Lynn teenager charged with fatally stabbing Rene Valdez during a drug rip-off this summer, despite strong objections that he remain held without bail by prosecutors.Salem Superior Court Judge Timothy Q. Feeley agreed to set the cash bail for Javon Walczak on Friday, but on the condition he must live with his grandparents, Paul and Theresa Walczak, at 208 Edgemere Road in Lynn.In setting the cash bail, the judge carefully discussed the obligations with the grandparents that they were undertaking as custodians before making his decision.As part of the bail conditions, the judge ordered that Walczak will be on house arrest and monitored by an electronic system. He is not to use drugs or alcohol inside his grandparents’ home, possess no firearms at the residence and he is to have no contact direct or indirect with witnesses or family members in the case against him.Family members of the victim, Rene Valdez, 16, of Medford, were obviously upset with the judge’s ruling, one male family member storming from the courtroom.Walczak is expected to make the bail within a few weeks, but won’t be released until the monitoring system is in place inside his grandparents’ home.Walczak stands charged with second-degree murder in connection with the Aug. 10 incident in the Highlands part of Lynn where Rene Valdez, 16, of Medford was killed and Darren Colucci, 17, of Swampscott, sustained a minor stab wound.