I have a Waters Micromass ZQ LCMS with MassLynx which I have been using for over a year.

I recently lost signal on the mass detector but have good signal on the PDA. The methods have not changed for my samples. There did not appear to be any blockage or contamination. I have cleaned the ion source components as well as replaced the ESI probe capillary, liners and ferrule on the probe I have been using.

I noticed that my source page capillary voltage did not change when the instrument was in operate. It normally is about 3.5kV for positive mode in operate and less than 1kV in standby. All other readbacks appeared normal. I tried a different ESI probe and observed the same. However, now the diagnostics 1 and 2 on the tune window diagnostics tab only remain red.

At this point, I am at the limit of what I can think to do myself. I am concerned that something within the detector may have stopped working. I was hoping perhaps someone with more experience in repair and maintenance could either give advice or confirm my concern before I call a technician.

Thank you,