Had exactly this problem yesterday. Had no idea how old these machines were! 1984. Anyway, slow fill in this case was caused by the a previous repairer switching the wires between the hot and cold solonoid valves. The hot valve has a restricter in it, the cold not.
Once switched back, it was fine. The 2 cold water solonoid wires have "cool" colours, the hot solonoid wires are "warm" colours.
Luke
January 2011