another autotune problem with the 5973

[kuzao]

hello i have a problem with the autotuning of the hp 5973 msd.
the overal abundance is a little bit low. the max abundance around 400 000 i read that 1.5mil to 2 mil is normal.. the EM is a little bit old and is normaly runnning on around 2000em volt.

when i perform an autotune the first peak is ok in shape but little bit low in abundance around 400 000

at the high mass peak autotune is failing and telling me 'couldnt achive line width' normaly my autotune peaks are 3 amu wide. in this case looks like the same width but its a split peak.

i check a few things: vacuum is ok, the rf coils are well adjusted, i checked all the tune parameter with a manual tune, the septum is new, the liner is new, the column is well cut and inserted in the transfere line. we also cleand the ion source...

we also asked the service technician but she has no idea how to solve the problem...

any ideas? help would be very welcome

alex

[Rick]

If 69 mass and 219 have a good shape but 502 is not o.k, verify the dc polarity

[kuzao]

yes thank you very much i guess that was the problem.
factory setting was negative but the instument was set to positive....
also getting better sensitivity (factor 2).

was strange didnt found much about it in the manual, just a half page.

thanks alex