Our Clarus 500 GC/MS was operating normally, but now I am getting only noise signal, no MS peaks.
The Source parameters and MS parameters were not changed.
This was an indication that the photomultiplier
tube was dameged, so I changed the tube. Unfortunately, no change - still only noise. Does anyone have experience replacing
the head amplifier? The procedure is described on pages 107/108 of Clarus 500 MS Hardware guide. Everything is clear, except the last point
says:

"Go to the Head Amplifier electronic adjustment procedure."

and this is all - no explanation how to adjust/check the Head Amplifier. Any suggestions,

Thank you very much,
Jan