Chromatography Forum

Hello,

I'm currently trying to revive an Agilent GCMS (5973/6890) and I encountered some issues.

I changed the brand new heater/sensor assembly for the ion source as I noticed one wire was broken when I tried to clean the ion source. After I turned on the MSD as well as the GC, everything looks ok except the MS Quad temperature, it always showed around 320 to 360, and never went down to the setpoint 150.

Is this caused by a defective Mass filter heater assembly (G1099-60172)? I checked the manual, but it seems this issue wasn't mentioned.

In addition, I am able to run a sample if I hit override button to ignore the MS Quad temperature setpoint, but it will show no GC and MS signal collected in the logbook, and there's no TIC at all. I'm not sure if it is the defective Mass filter heater assembly causing the issue.

Does any one have the similar experience? Any comment would be appreciated.

I assume you have checked the connections for the temp sensor.
Have you switched ends on the ribbon cable? If one of the wires in there is broken (it happens) the sensor will work but something else won't.

Are the quads showing 320-360C even when you first power on the instrument before it has had time to warm up?

If so then I would suspect the sensor, or as Steve mentioned a cable problem.

Thank you for your comments!

I also contacted Agilent service engineer regarding this issue, and like you mentioned, the service engineer said the quad heater/sensor is most likely the cause of the problem even though the wires looked intact. I've ordered heater assembly from Agilent and hopefully there's no other issue further into the electronics after I replace that parts.