Recently, one of my ICP-MS 7800s just stopped measuring in Analog mode. I've had 3 different Agilent techs out to look at it, and the P/A tune works fine, but when you run the instrument every single measurement is in P mode, no matter how concentrated. What could possibly cause the instrument to just stop running in analog mode? I've checked every meter, voltage, setting, flow rate, pressure, and temp possible.