GCMS 5973N Turbo Pump Not Pumping Down

[tung]

We have an Agilent GCMS 5973N where the turbo pump not starting up even though the rough pump was pumping down to 10^-4 torr. Does anyone know what might possibly could cause this? Thank you in advance!

[James_Ball]

If the bearing in the turbo pump has gone bad it will not pump down.

Is the turbo speed remaining at 0% or near 0%?

If you are comfortable removing the turbo pump you can test it by either blowing on the turbine, which should make it spin easily and it should continue to spin after you stop blowing on it, or if you sit the turbo pump bottom flat on the bench and twist the body quickly the turbine should remain almost motionless untill you stop moving the body. If the bearing is bad twisting the body will cause the turbine to move with the body, or will cause the turbo to stop immediately as you stop blowing on it. If it passes these tests then it could be a controller problem.

If you are not comfortable removing the pump, then it is best to call Agilent in for service.

Is there any message appearing in the instrument log?

[tung]

Thanks for the reply! I apologize for the late reply, somehow I did not get the alert that someone replied to the post.
Looks like it was the power supply to the turbo pump was bad. After the power supply was replaced, the turbo pump is working now.

[gapeev]

As suggested, take the covers off, check power, control signals to the pump controller -> determine if this might be a dead pump/controller. Act accordingly.
If not comfortable, call for service

Turbos usually make some fishy sounds before dying. And/or they become erratic going from 100% speed to some lower %% before making these fishy sounds or stop working at all

Good luck!