Chromatography Forum

I have a 5973 with a turbo molecular pump that we run every day. Someone walked by it the other day and noticed the rough pump was gurgling a bit too loudly. Upon investigation they found the side plate was open and the rough pump was pumping away while the MSD and GC were still turned on and in the middle of a run. No-one is really sure how this happened, but now I have to deal with the repercussions.

The source was cleaned and the rough pump replaced.

When you first pump the instrument down it scans fine but after awhile if you try to scan it it just says "Difficulty with the mass filter electronics".

I hooked up an ion gauge controller and it reads the vacuum at 1.5^-5 to 8.8^-6. These numbers are well within the acceptable limits so I do not think vacuum is the problem.

Any suggestions?

Thanks

Any idea what caused the loss vacuum? If I called my service guy with this problem he would bring a new side board along as a matter of course.

Absolutely no idea. One employee found it like that and told me about it.

Vacuum has not dropped since I pumped it back down. The ion gauge controler is now reading 7.7^-6.

It was scanning initially when I pumped it down, but now everytime I tell it to scan it just says: "difficulty with the mass filter electrinics"

"I hooked up an ion gauge controller and it reads the vacuum at 1.5^-5 to 8.8^-6." - these are a bit low; i.e. causing your MSD to fault.
Check to make sure you did not crush the column going in to the MSD, that your He flow is indeed high enough. Your pressure should read closer to 5E5, see if this corrects your problem. If not then I would look at both filaments, but if you indeed did clean the source, then the problems is probably the horn or some electronic issue.

Good luck.

Will

Your vacuum is in the range where both of my 5973s run. Have you tried a Microsoft reboot, ie turn everything off, unplug, plug in and restart?
A consistent error like that one says that some condition is out of range. Unfortunately the message doesn't tell you much about what is out of spec. So without without serious diagnostics you will be relying on dumb luck. Sometimes that's all it takes.

Good luck!

I relocated the entire side plate (door/board/analyzer and all) to another instrument to see if the problem is in that part of the MS or the other electronics and i soon begain getting the same error on the different instrument.

I then removed the board from the door and replaced it with one that I know is ok. It still get's the same error.

I am sure the problem lies inside the analyzer chamber now, and I am getting worried that something happened to the quads.

Any suggestions as to how to move forward?

Do you have a spare HED power supply? You may want to try swapping it out.

The HED supply is located on the board that is on the side of the door, correct?

I have replaced the board with another one that I know works and it still has the same error.

This Agilent document recommends cleaning the quad contacts or tuning the RF coils (or paying the good folks at Agilent to visit).

http://www.chem.agilent.com/Library/Sup ... a20405.pdf

The HED supply is located on the board that is on the side of the door, correct?

I have replaced the board with another one that I know works and it still has the same error.

The HED supply is in the electronics box below the door. Follow the "spark plug wire" for lack of a better term from the side board down. That wire is connected between the side board and electronics board. Before you get too carried away swapping electronics, or calling Agilent let's try a few easy things that I have seen cause this over the years. First, make sure that HED lead is fully connected at both ends. If you have another instrument, try swapping that lead and see if the problem goes away. Take the multiplier horn out and clean the contacts. I have seen multipliers loose good contact and give this error. Make 100% sure all the leads going to the source are in the correct position and making good contact. I have seen this error several times, but only once did I end up replacing any major parts.

Thanks for the input!

I will double check all of this (hopefully time will permit tomorrow) and see what happens.

Thanks for the input!

I will double check all of this (hopefully time will permit tomorrow) and see what happens.

No problem. If that still doesn't get you anywhere, let me know. There are some other things to check as well.

Hi Omaejel,

I'm not sure if you solved your problem, but here is my input.

We have a 5975 with turbo pump in our lab and had a similar problem about a year ago. We got the same mass filter electronics error. We were led on a wild goose chase for a while, but it turned out that the wires connecting the heater/sensor assembly on the source heater assembly weren't working. We operate our instrument in both EI and CI mode, so every time we switched the sources we were fiddling with that wire, until eventually the connection between the wire and heater/sensor assembly went bad. We had to replace the heater/sensor assembly, but fortunately they are now better designed and that connection is re-inforced. You could rule that out using a multi-meter.

Hi Omaejel,

I'm not sure if you solved your problem, but here is my input.

We have a 5975 with turbo pump in our lab and had a similar problem about a year ago. We got the same mass filter electronics error. We were led on a wild goose chase for a while, but it turned out that the wires connecting the heater/sensor assembly on the source heater assembly weren't working. We operate our instrument in both EI and CI mode, so every time we switched the sources we were fiddling with that wire, until eventually the connection between the wire and heater/sensor assembly went bad. We had to replace the heater/sensor assembly, but fortunately they are now better designed and that connection is re-inforced. You could rule that out using a multi-meter.

Usually when the ion sourse temp sensor fails you will get a temperature reading of either 512 or 0.