The school board of Caribou-based RSU 39 voted Wednesday to advance a budget with a projected $1.5 million increase over the previous year. The increase, which would raise the total budget to roughly $26 million, is almost 1% lower than the budget business manager Cristy St. Peter brought to the school board in mid-April. She attributed that drop to not filling vacancies and using other funding sources to cover some costs. If approved by voters,…