Margaret C. Pfister Memorial service for Margaret C. Pfister, a Northwest Portland homemaker, will be at 2 p.m. Saturday in Pegg, Paxon & Springer Chapel in Beaverton. Pfister died of cancer Tuesday in a Beaverton care center. She was 76. Born Margaret Ahrens July 28, 1912, in Ridgefield, Wash., she had lived in the Portland area since 1931. Survivors include her husband, Fred; son, John of Portland; daughter, Donna of Vancouver, Wash.; and two grandsons. Disposition was by cremation. The family suggests remembrances be contributions to the Oregon Division of the American Cancer Society. Special Instructions: The family suggests remembrances be contributions to the Oregon Division of the American Cancer Society.