Use manual tune to enter the m/z Range and m/z offset values from the last successful autotune or manual tune. These values should be accurate enough to allow the MSD to start tuning.
Increase the electron multiplier voltage. If the electron multiplier voltage is at or near its limit of 3000 V, you may need to replace the electron multiplier horn. See the MSD maintenance documentation for instructions for replacing the electron multiplier horn.
If the calibration vial is empty, you should see the error message: Not enough signal to begin tune or possibly No peaks found. If the vial is almost empty, you may instead see symptoms such as inconsistent peak widths.
Remove the upper MSD cover.
Check the PFTBA level in the calibration vial. If necessary, add PFTBA.
See the MSD maintenance documentation for instructions for refilling the calibration vial.
Remove the upper MSD cover.
Check the signal cable. Make sure it is securely connected to the side board.
Vent the MSD.
Open the vacuum manifold.
Inspect the electron multiplier. Make sure the braided wire is securely connected to the electron multiplier and the signal feedthrough. Make sure the pin on the electron multiplier horn is making good contact with the contact strip.
See the MSD maintenance documentation for instructions for venting the MSD and opening the vacuum manifold.
Vent the MSD.
Open the vacuum manifold.
Inspect the wiring to the ion source. Make sure all wires are securely connected to the feedthrough board and to the ion source. Make sure the correct wires are connected to the correct pins.
See the MSD maintenance documentation for instructions for venting the MSD and opening the vacuum manifold.