Chromatography Forum

Hello,

I am adjusting the coils of an Agilent 5975 MSD but cannot lower the voltages below 125 mv when working with mass 100.

Also, I am checking the test points as in the document:
https://www.google.com/url?sa=t&rct=j&q ... i=89978449

We leaked the foreline pump and have changed some parts, but still, I can see some oil in the pane, so I think the pump is not fully sealed.

Can somebody give me advice on the maintenance of the pump it is a Pfeiffer Duo2.5. I have all the parts for an overhaul.

I will try to reseal it. I have looked on the internet and they said that the first problem is the Vacuum so perhaps is there the problem. Also, I get 0.000 mTorr pressure in the display. It is not okay. As I have searched.

Will check the pump again. But can you give me some advice, please?

Adolfo Álvarez

Hi Adolfo

The first step is to ensure you repair the foreline pump to allow the vacuum reading display below 200 mTorr.
Until that happens the diffusion pump will not operate and no MS parameter will be meaningful.

Matt

Years ago, when I was first bringing my 5973 back to life, I had a problem with high RF voltage. I could bring numbers into line at low mass ranges, but by the time I'd hit 500 I was out of range of what the instrument would even report(FYI at least on a 5973 running G1701BA, when you hit 2000mv the reading "rolls over" and will read a very low value).

I was diagnosed with a faulty sideboard, but that didn't fix it.

Figuring I had nothing to lose, I removed the spring contacts where the wire "cage" delivers voltage to the quads, carefully cleaned those with solvent and a swab, and reassembled. Amazingly enough, ti came right back to life.

I just mention all of this as if you've sorted all your other issues and still can't get your RF in range, try this. Failing this, it's likely an electronics issue.

Since vacuum problems are one of the most common issues in MS systems, ensuring that the entire vacuum system, including the turbo pump and any connections, is properly sealed and functioning is crucial. A leak in any part of the system can cause poor performance and issues with mass accuracy and sensitivity. Mapquest Directions