I am trying to do an initial tune with our 6520A after I vented the instrument. Error occured while it was optimizing for Quad AMU and the error message is "No valid optimum found in ramp (abundances were all too low)".
Make sure that a TOF tune has been completed before starting a Quad tune.
From the tune screen, turn the QTOF on and manually turn the calibrant on by selecting bottle B in the lower left hand screen. Look at the spectrum. If the abundances are very low and/or peaks are missing then there is a hardware issue that is preventing the tune from completing.
Also, if you have an AJS (Agilent Jet Stream) source, make sure you are spiking the tune mix with the HP-321 from the bio reference kit. The Jet Stream obliterates much of the 322 ion. The 322 ion is fragmented for the quad tune, so if there is not enough of it the tune will fail.