We have a GC-MS Saturn 2000 Varian, it is a very useful equipment and cost effective. Currently we are calibrating it using FC-43 mass calibration compound. Unfortunately,even after repeated efforts we are getting six masses calibration ok, however it is missing last mass 614 during RF tunning. RF ramp is linear upto 520 m/z.The display range of RF ramp is between lowest 880 and highest 2048. The diagonstic display wrong RF voltage at DAC 3264, rest of the diagonstic is passed. Please suggest the solution.