Every one Happy New Year, We are having a problem with our Delta plus mass spec for the last two weeks. I posted this question 10 days ago. Let me put this in detail if someone has some helpful suggestions. Two weeks ago Box and Trap current went down from 0.8 and 0.7 to 0.6 and 0.9 mA, and after a day the values went to zero. We found out the filament was burned. I changed a new filament yesterday and Vac was good (3.3e-008 mBar) all the other settings are fine. High Voltage is 2.949 KV; Magnet 11591; HV 3.02 KV. When I turned on the source; Box and Trap current readings are 0.9 and 0.62 mA. It stayed the same; it seems to me still there is something wrong. According to the thermo manual the ratio of the “box current” and “trap current” should be 0.7 on box versus 0.7 on trap or further in favor for the trap current. “DEVIATION FROM THESE VALUES INDICATE UPCOMING PROBLEMS CONCERNING THE FILAMENT” I checked all the rotary pumps, all are pumping fine, we removed one of the small turbo pumps on the left side of the mass spec it is spinning fine. I DON’T know what else to think or try Anyone have any suggestions or comments on these problems. Anyone encountered this before. I will appreciate the help Thanks Million --------------------------------- Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.