Pump down

Unfortunately, if you have good foreline pressure and the turbo is not spinning up it is either the turbopump controller or the pump itself. Dan

Thanks Dan

My instrument  is new, It was installed 3 years ago and until now was off , It worked only 2 days!. Is it possible there was  so serious problem with pump or controller? Unfortunately Agilent does not support our instruments. A service man which works on vacuum pumps told us the pump is ok (after testing the pump on his workshop, actually he doesn't know anything about LC-MS and only works on vacuum pumps generally). Can we have more advice?

Thanks for help.

 

John, If your guy works on vacuum pumps he should have been able to verify that the controller was functional as well. Did he check the controller? Dan

Thanks John

He says the problem may be related to pump controller, AC board or main board. He is working on the controller now. Actually It's so difficult for me to accept there is an electronic problem for an instrument which worked only 2 days .

Unfortunately depending on the actual comtroller and pump you have, failures are not necessarily uncommon.  Even with little use.

 

Dan

You haven't specified the make and model of the Turbo and Controller.    If its an older Agilent LCMS it no doubt has an Edwards Turbo pump, Turbo controller and Turbo power supply.  All three must be in working order. 

An experienced, professional "vacuum guy" can take the turbo, controller and power supply and run them together in a fixture or even on a bench -   WITH proper safety precautions !  

              This is NOT for the inexperienced .... remember the

              Turbo spins at > 70,000 rpm.  

This can be done in complete isolation, away from the LCMS, in order to verify the Turbo and Controller.   If you have  ANY reservations, send it away to a professional company.

Now, sorry to jump in at such a late time .... but you also need to consider that the pressure gauges are not sending the "ok" to the controller.   

Thanks Sharpie

Unfortunatelly the vacuum guy has no idea about controller failure until now. He says it may be time consuming.

Can you please more explaine the last sentence in your post, :

"you also need to consider that the pressure gauges are not sending the "ok" to the controller

 

Do you mean there may be a problem with ion or foreline pump gauges? I changed the ion gauge with new one but I didn't change the foreline pump gauge because it showed pressure about 2 torr and it seems be Ok

 

What other cheks we can do?

 

OK, so we still don't know the make and model of the Turbo and Controller but no reputable "system" will allow a turbo pump to start its spin up unless there is at least some sufficient level of vacuum in the manifold.  The "OK", therefore must come from some sort of "low level" vacuum sensor, probably in the form of a TTL Hi or Lo or (less likely) Contact Closure.  The "OK" must be presented to the Turbo Controller.  If your "OK" signal does not come, the Turbo will not begin its spin up process.  

If your Turbo Pump, Controller and Power supply can be validated on the bench (or otherwise outside of the mass spec system), then your problem lies in the mass spec system,  somewhere in the logic.

In that case, in order to proceed, either you need more intimate knowledge of vacuum systems, or else at a minimum logic diagrams, or better yet schematics.

Hope this helps. 

Thanks Dear Sharpie

Last week the "vacuum guy" said there were electronic problems in power supply and after changing some ICs and capacitors on the board, the pump spin up properly on the bench.  Unfortunately, after pump installation on the instrument the problem was not solved and pump is not spin up.

Any help?

I believe I said this earlier and now you know the pump is spinning up, based on the service engineer, I would simply replace the controller. Dan