5973N tune issues

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

61 posts Page 1 of 5
In my continuing saga of bringing back my 6890+-5973 that was allowed to regurgitate foreline fluid into the diff pump I am having 2 main issues now the biggest of which is tuning. The other is it is not recognizing/detecting the 7673-1512 autosampler.

-I have 10^-6 torr vacuum with the new E2M2 and the serviced diff pump. However, I tried tuning it and the first time it barely competed it but turned the detector to 2600 when the last good tune was at 1300. Since then cannot achieve constant peak widths. The tune masses like either like blobs of peak, noise, or occasional flashes of good mass peaks.

-I took the source apart and cleaned it. Nothing popped out. insulators look good, it is missing the washer that sits behind the repeller nut and in front of the insulator but I just made sure not to over tighten it. Source was a bit dirty in the usual spots but not too bad.

-I tried restoring the tune file from setup. I also tried inputting the last known good values to give it a starting point.

-I also tried both filaments.

-The only thing that is hard to see is the calibrant level. It looks competely full but it is hard to tell as the vial is far into the collar so it is either completely full or completely empty.

-Vacuum goes down when tune starts so it looks like the valve is opening.

Might as well try dipping the coils. There's always the off chance that might work.

If it's an erratic issue in my experience it's either a wire that has been abraded and is shorting someplace or your detector has puked out.
In manual tune with calibrant valve open, how many peaks are present? You should see less than about 120. If you've got more than 200 I'd suspect serious contamination from the oil and would start there.

The one autotune that passed (em=2612) had 482 peaks. Now when I try to tune it looks like I get broad peak of peaks occasionally decent looking mass peak that when adjusted splits into several or sometimes grass. It won't go through any more tunes though. I tried inputting the last known good tune values and playing with it looking for nitrogen oxygen but I am not seeing much of anything.
I am starting to suspect the calibration valve as I just had a tune that looked like it was working fine. Peaks flashing and adjusting then all of the sudden nothing but grass and the tune stopped. It clicks and everything but sometimes it doesn't look like the ion vacuum guage changes when I start and the calibration valve opens.

Is there anyway to confirm and service the valve ie take it apart and send solvent though it to clean it.
You should be able to go to manual tune and toggle the valve on and off and watch the tune profile to confirm.
the trouble is I am not seeing much of anything on the manual tune scan. Even when I change the ions to look for air 28/32/18. I am going to try a new filament tomorrow morning.
Filament didn't help strongly suspecting calibration valve.

I put in in manual tune looking at m/z 28, 69, and 32, 18 is the base peak with 28 running about 2,000 and 32 about 250. I am opening and closing the valve and most of the time it clicks but noting changes on 69 once I caught it going to 189,000 while it is mostly staying at 1500-2000.

I wish I knew for sure. Is it possible to clean out the valve with some solvent say methanol to unstick it. It worked once on a 5890 EPC solenoid?
MSCHemist wrote:
-The only thing that is hard to see is the calibrant level. It looks competely full but it is hard to tell as the vial is far into the collar so it is either completely full or completely empty.

Maybe I haven't read the whole thread carefully, but have you checked PFTBA level in the vial ?
Yep almost full. Agilent is convinced it is an electronics board issue so looks like service call.

Also resolved the issue with the 7673. The G1512A controller box is fried. I pulled the one off my 5890 and now the autosampler is working fine but the box from the GC/MS won't talk with the 5890 system. So I either need a new 1512A or the parts to get my 7683 system installed in the GC/MS. Not sure if I need the g2912A controller board, the G2912 controller box, or I can rip the card out of my 6890N.

Edit: nope the 6890N is integrated. Need to purchase the internal kit for the plus.
You could try going to manual tune and injecting air into the injection port. When the air gets through the column you should see a spike in 28. That might help confirm that the valve isn't actuating and the mass spec is okay.
actually I'd rather try acetone and scan at m/z 58 I did just inject 1ul acetone manually 50:1 split while doing manual tune scan for 58/28. For a small instant at about 2 minutes ( 50 deg C db5 coln 30m .25mm .25um) I see a spike in 58 from 300 to 500000 for an instant. Though I should see a whole lot more given the amount.
carl.nott wrote:
Might as well try dipping the coils. There's always the off chance that might work.

Tried dipping the coils. They were already optimized. Any direction I turned the screws only raised the voltage reading. They were well within the manual's indicated normal minimum voltage readings for 100 (74) and 650 (450) amu.
Sounds like a bad top board. Had to replace mine once. Easy to do with out service. You just have to dip the coils after installation of a new board.
I think that is the most likely problem at this point. I'd rather have Agilent do it because I can't confirm this and I can't buy a $2500 board, and then risk having to tell my boss nope guess that wasn't the problem.

But yea the problem appears to be it is unable to direct ions from the filament to the detector. That is why I only saw a bit of acetone when I flooded the instrument with it.
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