Not enough Vaccum

[adler_LAB]

The MS doesnt have enough Vacuum. Its even to less to make a leak check. I already replaced the pump and the vacuum pump with no change so i put the old one back in. I also checked the fittings of the cards that connect the quatropoles. I changed the lockage; put a plug on where the coloumn normaly comes in. My next stepp is to change the valve to remove the vacuum and hope it helps.

I guess if the Ion gauge is the problem there would be a normal resolution with a bad vacuum in the display right ? Also maybe a plossibility that the RF board calculates the vacuum wrong since it messures it in stepps to controll the vaccum pump. But the pump spinns normal.

Any suggestions ?

[Peter Apps]

You have a massive leak somewhere - check all the flanges, transfer line seals, calibration vial holder etc etc.

Peter

[Don_Hilton]

What make and model MS are we talking about? Given that you are trying to do leak checking, I assume GC/MS. So, have you put a blind ferrule in the transfer line and looked at the vacuum? Can you install a blank flange in place of the transfer line? I assume you are getting an ionization guage reading? First check over the parts Peter listed. But sometimes a leak can still be hard to find. If so, you can take a wash bottle with isopropanol (not a smaller alcohol - we are going to depend on the viscosity of isopropanol here) and put a liquid film along the seals on the mass spec. When squirt a bit of isopropanol on the portion of a seal that is leaking - or isopropanol flows over the leak, it will plug or partially plug the hole before significant quantities evaporate into the mass spec. So watch the ionization guage reading for a drop in pressure, which may be only momentary, for a clue as to where the leak is.

A couple of cautions - 1) don't let the isopropanol wet things that should not get wet - like the electronics and wiring. 2) Isopropanol vapors are flamable, so use it away from ignition sources and keep the vapor levels low - as in: don't soak the whole instrument (or large portions) at once!

[adler_LAB]

Thank you for your quick help so far.

Its our really old Varian 1200 MSMSM

I put a plug in the hole where the transfer line comes in. I already thought about the calibration gas, theres a pug in there too. The only "holes" that i didn't check so far are the onces where the CI gas normally comes in (its has an EI ion Volume in it now; with a CI a leak check wouldn't work anyway ). And the one where the Air comes in when you vent.

I assume that the silver blue "tubes" are some sort of valves ?

I will also remove the hose from the collisiongas. to see if something is going on there.

I have almost every part as replacement, except for the turbo pump and the RF Board.